SECOND EDITIONFOUNDATIONS OF PHYSICAL

ACTIVITY AND PUBLIC HEALTH

Harold W. (Bill) Kohl, III, PhDUniversity of Texas

Health Science Center at HoustonUniversity of Texas at Austin

Tinker D. Murray, PhDTexas State University

Deborah Salvo, PhDWashington University in St. Louis

Library of Congress Cataloging-in-Publication DataNames: Kohl, Harold W., III., 1960- author. | Murray, Tinker Dan,

1951-author. | Salvo, Deborah, 1983- author.Title: Foundations of physical activity and public health / Harold W.

Kohl, III, PhD, University of Texas at Austin, Tinker D. Murray,PhD., Texas State University, Deborah Salvo, PhD, WashingtonUniversity in St. Louis.

Description: Second edition. | Champaign, IL : Human Kinetics,[2020] | Includes bibliographical references and index.

Identifiers: LCCN 2019027467 (print) | LCCN 2019027468 (ebook) |ISBN 9781492589976 | ISBN 9781492592822 (epub)

Subjects: LCSH: Exercise. | Public health. | Health promotion–methods.

Classification: LCC GV481 .K548 2020 (print) | LCC GV481 (ebook) |DDC 613.7/1–dc23

LC record available at https://lccn.loc.gov/2019027467LC ebook record available at https://lccn.loc.gov/2019027468

ISBN: 978-1-4925-8997-6 (print)

Copyright © 2020 by Harold W. Kohl, III, Tinker D. Murray, andDeborah Salvo

Copyright © 2012 by Harold W. Kohl, III, and Tinker D. Murray

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CONTENTS

PREFACEACCESSING THE WEB RESOURCEACKNOWLEDGMENTS

PART I    INTRODUCTION TO PHYSICALACTIVITY AND PUBLIC HEALTH

1         FUNDAMENTALS OF PUBLICHEALTH

Defining Moments in Public Health

Areas of Specialization in Public Health

Core Functions of Public Health

Public Health Law

2         FUNDAMENTALS OF KINESIOLOGYKinesiology Subdisciplines and Exercise Training

Principles of Exercise Training, Prescription, andPlanning

Applying Physical Activity and Exercise TrainingPrinciples

Health and Fitness Benefits of Physical Activity andExercise

3         INTEGRATING PUBLIC HEALTH ANDPHYSICAL ACTIVITY

History of Physical Activity and Public Health

Role of Physical Activity in Chronic DiseaseDevelopment

From Science to Practice and Back

Promoting Physical Activity for Health

Practitioners of Physical Activity in Public Health

4         MEASURING PHYSICAL ACTIVITYEvidence-Based Recommended Levels of Physical

Activity for Health

Laboratory Measures of Energy Expenditure

Electronic Devices to Measure Physical Activity

Direct Observation Techniques

Self-Report Instruments

Surveillance in Populations

Combining Measurement Approaches

PART II   HEALTH EFFECTS OF EXERCISEAND PHYSICAL ACTIVITY

5         CARDIORESPIRATORY ANDMETABOLIC HEALTH

Prevalence of Cardiovascular Disease

Risk Factors for Cardiovascular Disease

Kinesiology and Cardiorespiratory Health

Cardiorespiratory Fitness Assessments

General Recommendations for Cardiorespiratory Health

Prevalence and Economic Costs of Metabolic Disease

Metabolic Disease Risk Factors

Kinesiology and Metabolic Health

Common Tests of Metabolic Function

General Recommendations for Metabolic Health

6         OVERWEIGHT AND OBESITYCaloric Balance

Prevalence of Obesity and Overweight and AssociatedHealth Consequences

Obesity and Overweight Risk Factors

Obesity and Overweight Challenges

Kinesiology and Body Weight

Common Assessments of Obesity and Overweight

Physical Activity Guidelines for a Healthy Weight

7         MUSCULOSKELETAL ANDFUNCTIONAL HEALTH

Prevalence of Musculoskeletal Disorders and RelatedHealth Challenges

Risk Factors Associated With MusculoskeletalDisorders and Associated Health Challenges

Kinesiology and Musculoskeletal Health

Common Tests of Musculoskeletal Fitness or Function

Physical Activity and Musculoskeletal Health

Functional Health

Risk Factors for Poor Functional Health

Common Tests of Functional Health

Fitness Recommendations for Functional Health

8         CANCERSPrevalence of Cancers

Cancer Risk Factors

Kinesiology and Cancers

Physical Activity Among Cancer Survivors

Physical Activity Guidelines for Cancer Prevention

9         BRAIN HEALTHPrevalence and Economic Costs of Brain Health

Disorders

Common Brain Health Conditions

Risk Factors Associated With Brain Health Disorders

Physical Activity and Brain Health

Physical Activity and Brain Cognitive Function

Physical Activity Guidelines for Brain Health

10      HEALTH RISKS OF EXERCISE ANDPHYSICAL ACTIVITY

Musculoskeletal Injuries

Kinesiology and Musculoskeletal Injuries

Sudden Adverse Cardiac Events

PART III STRATEGIES FOR EFFECTIVEPHYSICAL ACTIVITY PROMOTION

11      INFORMATIONAL APPROACHES FORPROMOTING PHYSICAL ACTIVITY

Understanding the Community Guide

Rationale for Informational Approaches

12      SCHOOL-BASED APPROACHES TOPROMOTING PHYSICAL ACTIVITY

Rationale for School-Based Physical Activity Programs

Kinesiology and Physical Activity Outcomes for Youth

School-Based Physical Activity and Physical FitnessAssessments of Youth

Physical Activity in Children and Adolescents

International and National Trends in Youth PhysicalActivity Levels

School-Based Physical Education

Developmental Considerations for Physical Activity inYouth

13      BEHAVIORAL AND SOCIALAPPROACHES TO UNDERSTANDINGAND PROMOTING PHYSICALACTIVITY

Behavioral Theories and Theoretical Models ofBehavior Change

Social Support for Health Behavior Change

Individually Adapted Health Behavior Change Programs

Socioecological Model of Behavior

Social Support Interventions in Community Settings

14      ENVIRONMENTAL AND POLICYAPPROACHES TO PROMOTINGPHYSICAL ACTIVITY

Access

Urban Design

Measuring the Built Environment

Physical Activity Policy

Land Use Policy

Co-Benefits of Activity-Promoting Environments andPolicies

15      PROGRAM AND POLICYEVALUATION FOR PHYSICALACTIVITY AND PUBLIC HEALTH

Ways to Measure Program and Policy Effectiveness

Logic Models for Physical Activity Promotion andPolicies

Evaluation Designs

Data Collection and Analysis

Disseminating Results

16      PARTNERSHIP DEVELOPMENT ANDADVOCACY

Key Factors in Building Partnerships

Strategies for Physical Activity Advocacy

GLOSSARYINDEXABOUT THE AUTHORS

PREFACE

Welcome to Foundations of Physical Activity and Public Health,Second Edition. This text is a collection of the concepts that definethe emerging field of physical activity and public health. Much likethe more established fields (i.e., the effects of nutrition and smokingon public health), physical activity and public health has its roots inthe grafting of two other fields. In this case, public health scientistsand exercise scientists have come together to create an opportunityto improve health through research and promotion of physicalactivity. Methods and evidence from the public health sciences(epidemiology, health promotion, behavioral science, andenvironmental health) and kinesiology (exercise physiology, themovement sciences, and sport and exercise psychology), combinedwith a crucial eye on health policy, constitute our field. Althoughnothing can be substituted for experience, this text offers thebackground and introduction to the tools needed for the planning,implementation, and evaluation of physical activity promotionprograms. This is the first textbook of its kind designed for asemester-long course in the field.

Few singular health behaviors can have as broad an impact onthe health of individuals and populations as physical activity. Thescientific base is growing and solidifying regarding the effects ofphysical activity on all-cause morbidity and mortality due to multiplenoncommunicable diseases such as heart disease, some cancers,diabetes, and osteoporosis.

It is a very exciting time of growth in physical activity and publichealth. The seminal scientific works of Dr. Jeremy N. Morris and Dr.

Ralph S. Paffenbarger Jr. helped set the stage for what is now aworldwide focus on advancing the science, as well as reducingphysical inactivity and promoting the benefits of regular physicalactivity for the prevention and treatment of chronic diseases andother health challenges. As the science and practice advance,physical activity is receiving increased attention from policy andorganizational decision makers worldwide, including governmentalministers of health. Professional societies have been created tofocus on advancing the research and practice of the field, thescientific literature has expanded dramatically on multiple fronts, andphysical activity and inactivity are becoming parts of health policydecisions at all levels. An outstanding example is the TorontoCharter for Physical Activity: A Global Call to Action. This advocacytool drives policies worldwide that are supportive of the role ofphysical activity in promoting health.

HOW THIS BOOK IS ORGANIZEDFoundations of Physical Activity and Public Health is organized intothree parts and 16 chapters.

PART I: INTRODUCTION TO PHYSICAL ACTIVITY AND PUBLICHEALTHPart I introduces concepts of public health, kinesiology, andmeasurement. The chapters in this part highlight fundamentals ofeach and how they have come together.

Chapter 1 introduces the fundamentals of public health andprovides information about the various subdisciplines of public healthand how public health differs from medicine. Finally, there is adiscussion about how public health policy is often linked to the legaland regulatory system, as well as discussion of an emergingspecialization in public health.

The fundamentals of kinesiology are discussed in chapter 2. Inthe past, exercise was studied and often promoted as a means ofenhancing maximal performance rather than promoting basic health

benefits for all. The components of exercise training are presentedas well as the methods for applying them to target populations. Thegeneral health, fitness, and performance effects of physical activityand exercise are discussed. A final section presents ways tointegrate traditional exercise prescription into physical activity andexercise programs.

Chapter 3 focuses on the emergence of the subdiscipline ofphysical activity and public health. Examples of the interdisciplinaryinterest in the field of physical activity and public health are reviewedand the knowledge, skills, and aptitudes for careers in physicalactivity and public health are provided.

In chapter 4, the importance of measuring physical activity isintroduced, and the strengths and weaknesses of various laboratoryand field methods are discussed. Overviews of the followingtechniques are included: indirect calorimetry, doubly labeled water,wearable devices, direct observation, and self-report instruments.Observational techniques such as physical activity surveillance andsources of data-based comparison are also discussed.

PART II: HEALTH EFFECTS OF EXERCISE AND PHYSICAL ACTIVITYThe scientific base of the health effects of physical activity andinactivity is remarkable in its size and complexity. It continues togrow each year, and the overwhelming evidence for the healthbenefits and risks of physical activity provides much of the rationalefor action.

Cardiovascular and metabolic diseases and their association tophysical activity are presented in chapter 5. The chapter starts with adiscussion of the prevalence and economic costs of cardiovascularand metabolic diseases. Specific physiological, biomechanical, andbehavioral adaptations to physical activity and exercise are alsoidentified. Common testing methodologies for predicting anddiagnosing metabolic disease are provided. The evidence for theeffect of physical activity on cardiorespiratory and metabolic diseaseis discussed.

Chapter 6 contains common definitions for overweight and obesityand a discussion about the prevalence (U.S. and worldwide) and theeconomic costs of these conditions. A discussion of caloric balanceis included, and the contributions that physical activity and exercisehave on balance-related issues are highlighted. The various riskfactors associated with overweight and obesity are discussed, andspecific physiological, biomechanical, and behavioral adaptations tophysical activity and exercise are identified. Methods for assessingbody composition are provided. The effects of physical activity onweight loss, weight maintenance, and weight regain are discussedalong with the physical activity guidelines for achieving caloricbalance and a healthy weight.

Chapter 7 focuses on musculoskeletal disorders and functionalhealth. The risk factors, prevalence, and economic costs ofmusculoskeletal disorders and disability are discussed. Specificphysiological, biomechanical, and behavioral adaptations to physicalactivity and exercise are provided. Common testing methodologiesfor muscle function and functional health are included. The evidencefor the effect of physical activity on musculoskeletal disorders anddisabilities in functional health is discussed.

In chapter 8, cancers related to physical inactivity are discussedand the prevalence of each is highlighted. The mechanism by whichphysical activity might reduce the risk of some cancers is includedalong with a discussion of common risks for cancer. Specificphysiological, biomechanical, and behavioral adaptations to physicalactivity and exercise are identified. Included is a discussion ofscientific evidence supporting the benefits of physical activity forcancer survivors, as well as evidence for the role of physical activityin the prevention of cancer.

Chapter 9 examines the effects of physical activity on brain health.The prevalence, economic costs, and risk factors of brain healthdisorders are discussed. A framework for studying brain healthproblems and their response to physical activity interventions isprovided along with a discussion about the effects of physical activity

on brain function, which includes reaction time, learning tasks,cognitive function, and academic achievement. Therecommendations for physical activity complete the chapter.

In chapter 10, adverse events associated with physical activity arediscussed. Participation in regular physical activity and exercise mayincrease the risk of musculoskeletal injuries and sudden cardiacdeath in some cases. This chapter contains a discussion aboutdefining adverse events, the prevalence of problems, the risksassociated with injury, and the adaptive processes that may helpprevent injury.

PART III: STRATEGIES FOR EFFECTIVE PHYSICAL ACTIVITYPROMOTIONThe chapters in part III introduce evidence-based strategies forincreasing physical activity in individuals and populations. Publichealth is characterized by translating science into action to advancethe health of the population. The strategies presented in part III havebeen scientifically demonstrated to increase physical activity and canbe used for action in a variety of settings.

Methods for promoting physical activity are discussed in chapter11, which opens with a discussion about the importance of using theGuide to Community Preventive Services as a resource foridentifying physical activity intervention programs that work. Adiscussion about the impact of community-wide campaigns onincreasing physical activity is included along with an overview ofmass media campaigns.

In chapter 12, the rationale for school-based physical activityinterventions is presented. The scientific benefits of physical activityin youth are reviewed, and commonly used physical fitness tests forschool settings are discussed. A section that highlights current U.S.strategies and policies for promoting physical activity via school-based programs is included. The remainder of the chapter focuseson examples of evidence-based school physical activity programs.

In chapter 13, the focus is on evidence-based strategies forbehavioral and social approaches to physical activity promotion. Thischapter includes a discussion of current behavioral theories andtheoretical models that are used to explain physical activity behaviorin individuals. Social support strategies for physical activitypromotion in communities are defined and highlighted, and examplesof both types of approaches are provided.

In chapter 14, environmental and policy influences on physicalactivity are reviewed, as are strategies for change. The ways inwhich aspects of the physical and built environment can encourageor inhibit physical activity are reviewed. The role of urban design forphysically active populations and evidence-based strategies forchange are discussed.

In chapter 15, evaluation of physical activity programs isintroduced. This chapter begins with a discussion of the six-stepPhysical Activity Evaluation Framework developed by the Centers forDisease Control and Prevention (CDC). The concepts of formativeevaluation, process evaluation, outcome evaluation, and cost-effectiveness evaluation are covered. Logic models are presented.This chapter also contains discussions about evaluation designs,data collection and analysis, and publishing and communicatingresults.

Chapter 16 is the final chapter in the text; it focuses on buildingeffective partnerships for physical activity programs. Examples ofeffective partnering include the U.S. National Physical Activity Plan,the World Health Organization Global Action Plan for PhysicalActivity, and the international Toronto Charter for Physical Activity.Strategies for physical activity advocacy are included, and modelsfor advocacy and effective leadership conclude the chapter.

SPECIAL FEATURESThe content organization of Foundations of Physical Activity andPublic Health, Second Edition, is based on contemporary teaching

principles to maximize learning opportunities for students. Followingare the features in each chapter:

Objectives: summaries of take-away messages you should learnby reading and studying the materialOpening Questions: questions to help you think about how youcan use information in the textSidebars: examples of topics covered in the text, which will helpyou translate theory into practiceCase Studies: real-life examples of selected concepts coveredin the chapterLeader Profiles: mini-biographies of world leaders in physicalactivity and public health, all updated for the second edition;each leader addresses four key questions about his or her workin the fieldWhat You Need to Know: a bulleted review of the chapter tohelp you study the information providedBibliography: additional published resources for further study

NOTE TO STUDENTSAs the field of physical activity and public health expands, anincreasing number of job opportunities will be available for those whoachieve the core competencies as endorsed by the National PhysicalActivity Society, established in 2006 as the National Society ofPhysical Activity Practitioners in Public Health. Coursework thatcovers concepts of physical activity and public health will help futuregraduates in diverse employment settings such as public health andhealth care, business and industry, the nonprofit sector, education,mass media, urban planning and architecture, and parks andrecreation. University students in majors and minors such askinesiology, athletic training, physical therapy, medicine, nursing, andnutrition, as well as trainers in public services (fire, police, andmilitary), rehabilitation specialists, and wellness instructors will find anatural connection between their professional duties and the need

for promotion of physical activity and public health to colleagues andcommunities. Core competency areas covered by the text are listedat the end of each chapter in the “Chapter Wrap-Up” section.

Additionally, a new web resource provides a variety of interactiveactivities, includeing e-Media links, flash card activities, and studyquestions to help you learn and understand the informationpresented in the text.

NOTE TO INSTRUCTORSThis text is targeted for students in exercise science or public healthprograms who are enrolled in elective courses that expand theirunderstanding beyond what is taught in traditional core courses. The2018 Physical Activity Guidelines for Americans, the accompanyingPhysical Activity Guidelines Advisory Committee Report, and theCDC’s Guide to Community Preventive Services are valuableresources that provide much of the framework for the developmentof this text. You can find links to these in the web resource.

The following free ancillaries are also available to instructors whoadopt this textbook:

The instructor guide includes syllabus suggestions, teachingtips, and sample class assignments.The test package has over 300 questions, including multiple-choice, true-false, short answer, and fill-in-the-blank questions.The test package can be downloaded in multiple formats,depending on your teaching needs, and can also be modified toinclude test questions that you create.The image bank includes figures and tables from the text. Youcan use these items to create your own PowerPointpresentations, handouts, or other class materials.A new presentation package offers PowerPoint slides for eachchapter, outlining key points and including important figures fromthe text.

The web resource offers key term activities, e-Media links, anddownloadable study questions for each chapter.

These resources can be accessed atwww.HumanKinetics.com/FoundationsOfPhysicalActivityAndPublicHealth. The authors, who have taught courses in physical activity andpublic health, have helped develop all of the ancillary materials.

We trust that Foundations of Physical Activity and Public Health,Second Edition, will allow you to develop courses that inspirestudents to pursue careers in physical activity and public health.

ACCESSING THE WEBRESOURCE

Throughout Foundations of Physical Activity and Public Health,Second Edition, you will notice references to a web resource. Thisonline content is available to you for free upon purchase of a newprint book or an ebook. All you need to do is register with the HumanKinetics website to access the online content. The following stepsexplain how to register.

The web resource offers learning activities that focus on key termcomprehension, e–Media links, and downloadable study questions.We are certain you will enjoy this unique online learning experience.

FOLLOW THESE STEPS TO ACCESS THE WEB RESOURCE:1. Visit

www.HumanKinetics.com/FoundationsOfPhysicalActivityAndPublicHealth.

2. Click the second edition link next to the corresponding secondedition book cover.

3. Click the Sign In link on the left or top of the page. If you do nothave an account with Human Kinetics, you will be prompted tocreate one.

4. After you register, if the online product does not appear in theAncillary Items box on the left of the page, click the Enter PassCode option in that box. Enter the following pass code exactly

as it is printed here, including capitalization and all hyphens:KOHL-77ZK9-WR.

5. Click the Submit button to unlock your online product.6. After you have entered your pass code the first time, you will

never have to enter it again to access this online product. Onceunlocked, a link to your product will permanently appear in themenu on the left. All you need to do to access your onlinecontent on subsequent visits is sign in towww.HumanKinetics.com/FoundationsOfPhysicalActivityAndPublicHealth and follow the link!

Click the Need Help? button on the book’s website if you needassistance along the way.

ACKNOWLEDGMENTS

I am grateful for the past, the present, and the future. Mentors in mypast, especially Steven N. Blair believed in me and showed me thepath. Colleagues in the present keep me stimulated and motivated.My students in the future will be leaders in physical activity andpublic health. This second edition would not have been possiblewithout all of you.—HWK

Thanks to the leadership and staff at Human Kinetics for allowing usto complete this second edition. Thanks to Dr. Kohl for making thisnew edition a reality and to Dr. Salvo for joining our author team.Finally, thanks to my wife Mary for her love and support of all mywriting efforts.—TDM

There are many people that have helped me become the scholar Iam today. I thank each and every one of you for helping shape mycareer in public health. I would like to especially express mygratitude to Juan Rivera and Michael Pratt for your continuousguidance, support, and generosity.

I would also like to acknowledge that my professionalachievements would not have been possible without theunconditional love and support of my family. I dedicate this book tomy parents, Alfredo and Regina Salvo, for your patience anddedication. To Freddie, my accomplice and lifelong friend. To myhusband, Umberto, thank you for always helping me see the glass

half full, and for being my partner and best friend. Arturo — tambiénesto es para ti.

Last but certainly not least, I would like to express my immensegratitude to Bill and Tinker for inviting me to contribute to this work.Bill, thank you for believing in me and for your incredible support ofmy professional and personal growth. I am forever grateful for yourmentorship and friendship.—DS

PART IIntroduction to PhysicalActivity and Public Health

CHAPTER 1Fundamentals of Public Health

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The definition and history of public health»  The five main pillars of public health and how public health

has become specialized»  The five main principles that guide health promotion and

health education efforts in public health»  The 10 essential functions that support the core services

of public health

»  Why public health policy is often linked to legal andregulatory systems

»  The emerging physical activity specialization in publichealth

OPENING QUESTIONSWhat comes to mind when you read the words public health?

»  Screening children for nutritional deficiencies?»  Immunization programs to prevent an outbreak of influenza?»  Disaster responses to prevent disease transmission during and

after a hurricane or earthquake?

»  Prenatal education for expectant mothers?

»  Promotion of physical activity to lower the burden ofchronic, noncommunicable diseases such as heart disease anddiabetes mellitus?

If you answered yes to any of these questions, you are correct.Public health is all this and more.

Public health is a field that encompasses many disciplines in aneffort to promote and protect health and prevent disease anddisability in defined populations and communities. Although medicineand medical training are integral to public health, particularly inunderstanding the mechanisms of disease transmission, medicine ismore interested in the treatment of and cures for diseases anddisabilities in individuals. The key difference between public healthand medicine is that public health has traditionally focused less onindividuals and treatment and more on populations and prevention.

Therefore, public health should focus on problems that affect, orcould affect, a substantial portion of the population. For this reason,rare diseases and disabilities and seemingly random health eventsare often less of a concern to the public health field than problems

that may affect many people in a population. This is not to say thatsuch situations are not important, particularly to the people afflicted,but rather, that the focus of public health is on the health of thepopulation as a whole. Overall, the health of a population is rarelyimproved by focusing only on rare diseases and health problems thataffect the few.

This first chapter offers an overview of the principles and keyareas of public health and describes the fundamental services ofpublic health. Happily, public health has grown far beyond its originsand has allowed populations to thrive in the face of new andemerging health problems.

DEFINING MOMENTS IN PUBLIC HEALTHAlthough a complete treatment of the history of public health isbeyond the scope of this chapter (it could, and does, fill wholebooks), an understanding of some defining moments in public healthis instructive. This understanding helps contextualize the emergenceof physical activity and public health as a separate discipline withinpublic health. Winkelstein (2011) offers a more complete treatment ofthe history and evolution of public health.

Although disease and epidemics have occurred for thousands ofyears, the earliest roots of organized public health emerged in themid-14th century. At the time, the Black Death (bubonic plague)ravaged Europe, killing an estimated 25% of the population. As weknow now, the disease was tied to the black rat, the rat flea(Xenopsylla cheopis) that lived on the blood of the black rat, and thebacterium Pasteurella pestis that helped the flea to seek outadditional food by biting warm-blooded humans. At the time,however, an understanding of the germ theory of infection anddisease (i.e., that microorganisms are responsible for sickness andnot simply “bad air” or other nonbiological reasons) was still 400 to500 years in the future. Advances in transportation (shipping) aroundEurope and the Middle East spread the disease to other geographicareas. Although no one knew when or how the disease would strike,

public health was advanced by the creation of health boards andsystems for counting and collecting the dead. Unknowingly, this wasthe first attempt at a vital statistics system, which is now routine inpublic health organizations throughout the world.

Although the cause of the bubonic plague was unknown in itstime, counting the dead was one of the first examples ofcreating public health statistics. Can you think of examples oftracking modern diseases to the source?

Another advance in public health grew out of concern about thehealth of workers (particularly children) and the deplorable workingconditions that were rampant early in the industrial revolution of the19th century. Little regulation was in place at the time, andworkplaces were polluted, unsafe, and very conducive to diseaseand injury. Young children were working to support families, and thepoor and less advantaged were particularly susceptible. Theassociation between poverty and health was recognized early in the19th century, and policies and programs to address such disparitiesbegan to emerge. Edwin Chadwick in Great Britain was an earlyleader in the cause of improving sanitation, housing conditions,worker safety, and garbage disposal practices in poor communities.This is one of the first examples of using policy and legislation toimprove health.

The lens of history points to the early 20th century as anothercritical period in the history of public health. With the legitimization ofthe germ theory of disease transmission by Robert Koch and LouisPasteur (working independently) in the late 1800s, new methods fortreating (and preventing) disease emerged. Sanitation, quarantine,and other methods for controlling infectious diseases becamestandard practices in cities. Boards of health were developed to dealwith health threats to the community. Vaccines and antibiotics werediscovered and quickly resulted in monumental improvements indisease control.

The 20th century represents a bridge between a focus oninfectious (communicable) diseases and a focus on chronic(noncommunicable) diseases. Once infectious diseases werebecoming less influential, nutritional diseases (due largely tomicronutrient deficiencies) became a priority. Maternal and childhealth was also a critical piece of the public health puzzle in the 20thcentury. The infant mortality rate, as well as the maternal mortalityrate, was abominable. Mandating training and licensure of midwiveswere public health interventions that helped to control this burden.

Finally, following the decline of infectious diseases and nutritionaldeficiency diseases, the mid-to-late portion of the 20th century waswitness to the emergence of chronic diseases (also known asnoncommunicable diseases) as those that had the largest populationreach and thus were a substantial public health concern. Heartdisease, diabetes mellitus, cancers, mental health disorders, andmusculoskeletal disorders firmly replaced infectious and nutritionaldiseases as key causes of death and illness in the world. To bespecific, a 2018 report by the World Health Organization (WHO2018) detailed that more than 60% of all deaths worldwide in 2016were due to chronic diseases (see table 1.1).

Table 1.1   Ten Leading Causes of Death Worldwide in 2016Cause Deaths in millions % of deaths

Ischemic heart disease 9.43 16.6

Stroke and other cerebrovascular diseases 5.78 10.2

Chronic obstructive pulmonary disease 3.04 5.3

Lower respiratory system infections 2.96 5.2

Alzheimer’s disease and other dementias 1.99 3.5

Trachea, bronchus, and lung cancers 1.71 3.0

Diabetes mellitus 1.60 2.8

Road traffic accidents 1.40 2.5

Diarrheal diseases 1.38 2.4

Tuberculosis 1.29 2.3

Reprinted by permission from World Health Organization. Global Status Report on NCDs.(Geneva, Switzerland: WHO). www.who.int/chp/ncd_global_status_report/en/index.html.Accessed 16 June 2011.

Only 150 years in the past, infectious diseases were the leadingconcern and the primary cause of sickness and death. Today,diseases influenced by lifestyle and genetics are the greatest publichealth concern. This remarkable transition in public health coincideswith the beginning of the physical activity story.

AREAS OF SPECIALIZATION IN PUBLIC HEALTHAn important part of the evolution and history of public health hasbeen the emergence of training programs and techniques to addresspublic health challenges. The establishment of the London School ofTropical Medicine and Hygiene in the United Kingdom, and of theJohns Hopkins School of Public Health in the United States, in theearly 20th century were key steps to creating a workforce with theskills necessary for handling public health problems. Following theseearly efforts, additional training and certification of academicprograms took hold very rapidly in the United States. In 2011, theUnited States, Canada, and Mexico had 66 accredited schools ofpublic health providing leadership and training opportunities formaster’s and doctoral students. These training programs have

evolved over the years, resulting in widely accepted standards forareas of training and specialization in public health.

Figure 1.1 illustrates the five broad areas of specialization, orpillars, of public health, each of which contributes uniquely to thefield.

EPIDEMIOLOGY AND DISEASE CONTROLEpidemiology is the basic science of public health. The wordepidemiology comes from Greek origins: epidemia (“on people”) and-ology (“to study”). Although several definitions exist, a modern-daydefinition of epidemiology is “the study of distributions anddeterminants of disease and disability in populations” (Mausner andBahn 1974). Notable in this definition, and following from thepreceding discussion, is the word populations. Epidemiologists arefocused on a defined population and how a disease or disabilityaffects that population. What causes the spread of the disease ordisability? How can it be prevented? How many people are affected?What types of people or other organisms are possibly affected morethan others? Who is at risk? How many could be affected in thefuture? These are all questions that epidemiologists are trained toanswer.

Figure 1.1   Five pillars of public health.

Epidemiology is a quantitative scientific discipline that reliesheavily on statistics and study design. With the transition in the 20thcentury to disease burden being attributed primarily tononcommunicable diseases, epidemiological methods have evolvedto apply not only to infectious disease outbreak investigations, butalso to studies of longer-term chronic disease investigations. Forexample, much of what we know about risk factors for heart disease(e.g., poor lipid and lipoprotein profile, high blood pressure, cigarettesmoking, physical inactivity) came from early and ongoingepidemiological studies of (mostly) men with and without thesecharacteristics. Researchers used epidemiological methods tocompare and contrast study participants with and without theconditions, and then calculated the risk associated with theoccurrence of a disease. These techniques have evolved as theneed to address more complicated analytical questions hasincreased.

KNOWLEDGE INTO ACTIONPublic health science is characterized not just by theaccumulation of new knowledge, but also by the applicationof that knowledge to improve health. Public healthresearch must be able to be translated to action fordisease prevention, health promotion, or both.

ENVIRONMENTAL HEALTHThe environment can be defined as “all that is external to the hostorganism” (WHO 2011b)—including physical, biological, and culturalinfluences. Our physical environment (i.e., where we live, work, andplay) has a powerful influence on our health. The air we breathe, thewater we drink, the food we eat, the safety of our work environment,our exposure to radiation, and the ways we control theseenvironmental influences can promote or hinder public health. Thus,a large part of public health addresses environmental health.

Major advances have been made in public health as a result ofenvironmental health studies. Prohibition of lead-based paint toreduce the risk of learning disabilities in children, fluoridation of watersupplies to reduce dental problems in communities, air qualityregulations for automobile manufacturers and industrial polluters topromote cleaner air and water, and food safety standards to reducethe risk of food-borne diseases are all examples of public healthinitiatives that came about as a result of environmental healthstudies. Can you think of others?

Clearly, environmental influences on health have been known forcenturies. Systematic approaches to studying environmentalinfluences on health, quantifying these influences, and prioritizingresources and approaches to eliminate health hazards have beenadvanced only relatively recently. We will learn in chapter 14 that ourunderstanding of the role of the environment in promoting orinhibiting physical activity has advanced rapidly since the mid-1990s.

We can now identify barriers and correlates in the physical, social,and cultural environments that influence physical activityparticipation. This has been, and will continue to be, a major growtharea in the field of physical activity and public health.

The construction of bike- and pedestrian-friendly routesincreases access to places to be active in a community. Inaddition to physical activity, what are other benefits of suchefforts?

HEALTH PROMOTION AND HEALTH EDUCATIONWhy do some people exercise consistently, avoid tobacco, eat well,use alcohol responsibly, avoid illicit drugs, see their doctors regularly,and do other things necessary for health maintenance, whereasothers do not? How can we best teach basic health concepts forlasting effectiveness? What is the most effective education strategyto improve birth outcomes for teenage mothers? How canpopulation-level health behaviors be changed to maximize lifeexpectancy and quality of life? Questions such as these are routinelyaddressed in the health promotion and health education pillar ofpublic health. Although the environment and our genetic makeupcontribute substantially to our health status, how we deal with health

threats through our behavior has become a major focus of publichealth.

Much of the basis for health promotion and health education inpublic health comes from the concept of social justice, which iscentral to many ideas of public health. Social justice in public healthrefers to the assumption (some call it an imperative) that the healthburdens and benefits in a population should be distributed equitably.We have known for centuries that poverty is a predictor of disease,disability, and poor quality of life. Those who promote healthpromotion and health education strategies in public health aim to bepart of a solution to reduce such disparities.

The WHO has advanced five principles to guide health promotionand health education efforts in public health (WHO 2011b). See thehighlight box WHO Principles of Health Promotion for a descriptionof these principles.

WHO PRINCIPLES OF HEALTH PROMOTIONEmpowerment and InclusionHealth promotion should empower all individuals andcommunities to take some responsibility for the influenceson their personal health.

Intersectoral CollaborationHealth promotion programs should be directed at all therelevant determinants or causes of health and shouldtherefore include relevant collaborations among agenciesand sectors with influence beyond the health or medicalcare sector.

MultidimensionalHealth promotion initiatives should use all tools possibleto minimize health hazards and promote positive health.These dimensions include, but are not limited to,communication, legislation or policy, education, communityor organizational change, and finance.

Participatory

Health promotion programs should strive to be inclusive atall steps and seek to maximize participation individuallyand collectively.

AdvocacyAll people with an interest in health, including medicalcare systems, should take responsibility for healthpromotion and health education.

Based on WHO 2011b.

HEALTH ADMINISTRATION AND POLICYHealth administration and policy is the fourth pillar of public healthand focuses on the delivery of public health services. This area ofexpertise addresses important skills such as budgeting, policydevelopment and analysis, planning and prioritization, andcommunication. In keeping with the theme that public health is actionoriented, health administration and policy skills support theappropriate implementation of programs that, theoretically, arederived from research in the area. A good example lies in theHIV/AIDS epidemic. Research has shown that needle exchangeprograms likely reduce hypodermic needle sharing amongintravenous drug users and thus decrease the risk of transmission ofHIV/AIDS (Palmateer et al. 2010). Health administration and policyexperts can use such data and the results of studies to plancommunity-based projects that promote such programs.

In the field of physical activity and public health, the effects ofpolicies and program administration are an emerging knowledgebase. As addressed in part III of this textbook, policies for providingplaces to be physically active are showing promising results for thepromotion of physical activity. Expertise in health administration andpolicy is critical for the implementation and evaluation of such efforts.

BIOSTATISTICS AND DATA SCIENCEPublic health relies on both qualitative and quantitative methods tomove from knowledge to action. Biostatistics provides the basis for

the quantitative branch. Is the difference between two interventionsto promote breast cancer screening in a community due to the effectof the intervention, or simply due to chance? What is the predictednumber of cases of influenza in the upcoming year? Using statisticalapproaches, can future health care costs be accurately predicted forchildren born this year? Based in mathematical theory, biostatisticsallows for the practical and rational analysis of data, theinterpretation of study results, and the translation of those resultsinto action. Biostatisticians and epidemiologists work closely toadvance the science of public health.

CORE FUNCTIONS OF PUBLIC HEALTHEven with the specializations in public health listed earlier, the corefunctions of public health professionals and agencies must bedefined. What should these professionals and agencies do? Howdoes a public health agency interact with the medical care system topromote and protect the health of communities? Do standards forpublic health practice exist? In 1999, a joint project led by the U.S.Office of Disease Prevention and Health Promotion (ODPHP 2011)was created to describe and define the fundamental services ofpublic health. The Public Health Functions Project used thisopportunity to strengthen the public health infrastructure in theUnited States by developing and describing a common set of primaryservices that define public health. By addressing these functions, incombination with skill sets learned in the topic areas of the five pillarsof public health, professionals can effectively promote public health.The 10 essential functions of public health are listed in figure 1.2.

The 10 essential functions of public health help define and guidethe core services of public health. Competencies in the functions aredeveloped through training in and across the five pillars. Actually,these functions go beyond a simple listing—they have been adoptedas the key organizing framework for the CDC’s National PublicHealth Performance Standards Program (NPHPSP 2011). Thepurpose of the NPHPSP is to improve the quality of public health

practice and the performance of public health systems by providingperformance standards, engaging and leveraging partnerships,promoting continuous quality improvement, and strengthening thescience base for public health practice improvement.

These 10 essential functions are meant to interact in a cycle (seefigure 1.2) to maximize public health. The assessment phase beginsthe cycle with the monitoring of health and the diagnosis andinvestigation of important or emerging health problems. Policy anddevelopment ensues, including informing, educating, andempowering people regarding health threats, mobilizing partnershipsto deal with those health threats, and developing policies to minimizethreats and promote health. During the assurance phase, laws andregulations are created and enforced, linkages to care are created, acompetent workforce is developed, and effectiveness is evaluated.The cycle can then begin anew with ongoing monitoring. Importantly,this cycle revolves around research advances and administration(management) skills. Can you think of a specific public healthproblem and apply steps to each of the 10 essential functions?

As addressed in this text, physical inactivity is a public healthproblem that can be viewed as a content area addressed in terms ofthese essential functions. Each function can and should supportphysical activity promotion. Public health professionals with interestand expertise in physical activity can make this happen.

LEADER PROFILERoss Brownson, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?I have intersecting personal and professional interests inphysical activity and public health. Physical activity hasalways been an important part of my life. I grew up inwestern Colorado, and I was always active in sports,hunting, and fishing. My days in competitive athletics areover but I am still physically active every day. In myprofessional life, one of our first grants that was fundedby the CDC was a cardiovascular disease interventionproject in the southeastern “bootheel” region of Missouri.This project initiated a series of interventions topromote physical activity in rural communities by buildingand promoting the use of walking trails.

Did any one person have a major influence on your career?How?I have been lucky to have had many great mentors in mycareer. One person who stands out is John Bagby; he wasthe department chair and part of my dissertation committeeduring graduate school. He later hired me for my first jobin public health practice during his time as a divisiondirector with the Missouri Department of Health. John hadbeen deputy director of the CDC and led the campaign toeradicate malaria. His vast knowledge of public healthpractice, and his energy, integrity, and positive outlookhave guided me since we first met in 1980.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?

I am particularly interested in promotion of physicalactivity in disadvantaged populations—this includes ruralcommunities, racial and ethnic minority populations, andlow- and middle-income countries. Much of my currentresearch focuses on implementation science, which seeks tobridge the gap between what we know will improve health(effective interventions) and application—theimplementation and continuation of evidence-based programsand policies. The first study on physical activity andhealth was published in 1953, yet it was not until decadeslater that we developed evidence-informed policies andprograms to address physical activity. Much of thisresearch focuses on accelerating the uptake of evidence-based interventions in state and local public healthagencies. I am also focused on training and mentoring thenext generation of researchers and practitioners. Forthose of us in the later stages of our careers, this is acrucial area on which to concentrate.

Why do you do what you do?I often say that being a college professor is the best jobin the world because you get to choose the topics toresearch and courses to teach and you’re always learning.Having worked in a state health department and in theuniversity setting, I find it fulfilling to bridge thescience of physical activity promotion with practicalapplications of research. It is exciting to see thelasting impacts of our projects (e.g., walking trails)that are now a part of many communities.

What are two key issues that must be addressed by 2030?We have written about macro-level forces of changeaffecting public health (Erwin and Brownson 2017). Amongthese forces are climate change and rapid demographictransitions (i.e., the aging of the U.S. population andthe increasing proportion of racial and ethnic minoritypopulations). The intersection of physical activityresearch and practice with these forces of change iscrucial for our future ability to understand and promotephysical activity. Another related area of focus for thefuture is workforce development in public health practice.The retirement of baby boomers provides new opportunitiesand challenges. We need to fill jobs in public healthpractice with skilled professionals who are equipped with

more traditional skills (e.g., epidemiology, evaluation)but also new capabilities (e.g., systems thinking,communication, policy analysis) that are sometimeslacking.

Figure 1.2   Cycle of the 10 essential functions of public health.

PUBLIC HEALTH LAWAlthough efforts have been made to promote health and behaviorchange among individuals in a population, many times the beststrategy for making meaningful changes in public health is throughthe legal system, regulatory system, or both. Indeed, many of ourmost important public health successes have come from suchchanges: immunization laws for school children to prevent thetransmission of infectious diseases at school, legislation andregulations to prohibit cigarette use in public places to reduce

exposure to secondhand smoke, motorcycle helmet laws to reducetraumatic brain injury and death among riders involved in accidents,minimal workplace safety standards and inspections to reduce therisk of occupational injuries, and food safety and transportationstandards to reduce the risk of food-borne illnesses. Theseadvances in public health did not rely on individual or community-generated changes, but instead on legal or regulatory action.

Such legal avenues have given rise to an entire area ofspecialization called public health law. Specialists in this field seekto leverage legal and governmental authority to promote and protectthe health of populations. Experts in public health law, particularly asit relates to issues of preparedness with the emergence ofbioterrorism threats (e.g., anthrax), mass disasters such asearthquakes and hurricanes, and possible disease pandemics suchas avian influenza, have developed strategies and approaches aswell as research agendas to move the field forward toward optimalhealth protection. They constantly deal with the issue of balancingindividual rights with the moral obligation to minimize risks in apopulation.

FUTURE OF PUBLIC HEALTHPublic health is a vast discipline encompassing manyspecialties and functions. At the core, public healthseeks to promote and protect the health of populations.With health threats continuing to emerge as developedcountries face new challenges and developing countriesface the challenges of modernization, public health shouldbe used to predict these threats and respond accordingly.Physical activity and public health is a new subdisciplinein this area that bridges the traditional areas of publichealth and kinesiology. Large, unexplored areas need to beaddressed in physical activity and public health, many ofwhich will be introduced throughout this textbook.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

Public health is a field that encompasses many disciplines inan effort to promote and protect health and prevent diseaseand disability in defined populations and communities. Thekey difference between public health and medicine is thatpublic health has traditionally focused less on individuals andtreatment and more on populations and prevention.Public health encompasses health strategies that can beimplemented collectively but are impossible or impractical toapply individually.Chronic (noncommunicable) diseases have replacedinfectious diseases as leading causes of death in the world.Epidemiology is the basic science of public health.The five pillars of public health are epidemiology and diseasecontrol, environmental health, health promotion and healtheducation, health administration and policy, and biostatisticsand data science.There are ten essential functions of public health that helpdefine and guide the core services of the field. Competenciesin the functions are developed through training in and acrossthe five pillars.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in the

text. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYErwin PC, Brownson RC. 2017. Macro trends and the future of

public health practice. Annual Review of Public Health 38: 393-412.

Mausner J, Bahn AK. 1974. Epidemiology: An Introductory Text.Philadelphia: Saunders.

Palmateer N, Kimber J, Hickman M, Hutchinson S, Rhodes T,Goldberg D. 2010. Evidence for the effectiveness of sterileinjecting equipment provision in preventing hepatitis C andhuman immunodeficiency virus transmission among injectingdrug users: A review of reviews. Addiction 105: 844-859.

U.S. Centers for Disease Control and Prevention. 2011. NationalPublic Health Performance Standards Program.www.cdc.gov/nphpsp/index.html. Accessed 17 June 2011.

U.S. Department of Health and Human Services, Office ofDisease Prevention and Health Promotion. 2011. Public HealthFunctions Project. www.health.gov/phfunctions/Default.htm.Accessed 16 June 2011.

Winkelstein W. 2011. History of Public Health.www.enotes.com/public-health-encyclopedia/history-public-health. Accessed 16 June 2011.

World Health Organization. 2011b. Milestones in HealthPromotion: Statements From Global Conferences.www.who.int/healthpromotion/milestones/en/index.html.Accessed 16 June 2011.

World Health Organization. 2016. Global Status Report on NCDs.www.who.int/chp/ncd_global_status_report/en/index.html.Accessed 16 May 2019.

World Health Organization. 2018. The top 10 causes of death.https://www.who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death?f5tp=1. Accessed July 2019.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.4.1, 1.4.2, 1.4.3, 2.1.1, 2.2.1, 2.4.1, 2.4.6, 3.3.1,3.3.2, 3.4.2, 3.4.3, 4.3.3, 5.1.1

CHAPTER 2Fundamentals of Kinesiology

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The field of kinesiology and how its subdisciplines havecontributed to our understanding of exercise, physicalfitness, maximizing performance, and the shiftingparadigm of the promotion of public health benefitsthrough physical activity

»  The concept of sedentary behavior and the importance ofencouraging individuals and populations to adoptphysically active lifestyles that meet or exceed minimalrecommended national standards for health

»  The concepts and principles of exercise training»  The general health, physical fitness, and performance

effects of physical activity and exercise»  How to integrate the principles of traditional exercise

prescription programming for individuals—principles thatfocus on improved health outcomes while consideringfactors like age and mental and physical health—intophysical activity and exercise plans for populations

OPENING QUESTIONS»  Do you know the areas of kinesiology that positively affect

individual health, physical fitness, and peak performancethrough the traditional exercise training model?

»  How can knowledge of the fundamentals of kinesiology andexercise training help you promote health and physicalfitness for populations in a public health model?

Chapter 2 introduces the field of kinesiology and the basic conceptsof exercise training that have been used since the 1960s and 1970sto improve individual human performance and physical fitness(otherwise known as the traditional training model). You will learnhow the traditional model of exercise training, based on the scienceof kinesiology, has evolved to include the promotion of public health.The emerging concept of promoting public health by increasingphysical activity through the use of physical activity plans forpopulations is introduced at the end of the chapter and described inmore detail in chapter 3.

Before we begin our discussion of kinesiology, it would be helpfulto define some of the terms we will be using. Sedentary behavior isany waking behavior characterized by an energy expenditure of ≤1.5METs (1 MET is equal to resting energy expenditure; see the Volumeand Dose Response section for more information) while sitting,reclining, or lying. The majority of office work, driving a car, andsitting while watching television are examples of sedentarybehaviors. Sedentary behavior and sedentary activity are similar butnot synonymous; both are limited to energy expenditures ≤1.5 METs,but sedentary activity includes standing. Specifically, sedentaryactivity is activity requiring 1.0 to 1.5 METs, such as sitting andreading, watching television, or standing quietly.

Physical activity is any bodily movement that recruits skeletalmuscles and results in energy (i.e., calorie) expenditure (Caspersenet al. 1985). Moving your arm up and down at your desk,skateboarding, lifting sacks of groceries out of the trunk of your car,and running a marathon are all types of physical activity. Exercise isa specific type of physical activity that is planned, repetitive, anddone for a specific purpose (e.g., to improve health or physicalfunction, physical fitness, or peak performance) (Caspersen et al.1985). Walking the dog for 2 miles (3.2 km) every night, training for asoccer tryout, swimming laps, and working out at a gym are allexamples of exercise. Athletes who train to improve components oftheir physical fitness are doing exercise. Anyone who gets out of bedin the morning is doing some kind of physical activity.

In contrast to physical activity and exercise, physical fitness is aset of measurable physiological parameters (like cardiorespiratoryendurance [aerobic power], skeletal muscle endurance, skeletalmuscle strength, skeletal muscle power, flexibility, balance, speed ofmovement, reaction time, and body composition) (Caspersen et al.1985). Most people have their own views of what physical fitnesslooks like. What’s yours? An Olympic-caliber weightlifter? Amarathon runner? The fastest kid on the basketball court? How

about your grandparents who are happy and able to physically doeverything they want to do without limitations?

Figure 2.1 shows how physical activity can be promoted forindividuals or populations based on specific goals like avoidingsedentary behavior, improving health and physical function, andimproving physical fitness or peak performance. The physicalactivity and exercise continuum is included in the figure as anemerging concept that shows one should become physically activewhile avoiding sedentary behaviors and seeking to achieve specifichealth, physical fitness, and peak performance based on individualor population goals (Murray et al. 2019). It is important to understandhow to develop individual- and population-based physical activityprograms and to educate others about how to avoid regressing tolong-term sedentary behaviors.

The following sections of chapter 2 and chapters in part II of thetext provide details about how to develop and implement physicalactivity and exercise programming to achieve important physicalfitness outcomes that focus on improved health and consider factorslike age, and mental and physical health. You will also learn aboutkey training components (frequency, intensity, time, and type [FITT])and key training principles like overload, specificity, and progressionand adaptation to help individuals with effective physical activity andexercise programming.

Figure 2.1   Integration of specific needs, goals, and outcomes with physicalactivityBased on concepts from USDHHS, PAGAC (2018).

Fitness can be measured or estimated in the very tightlycontrolled setting of a laboratory or in field settings in which groupsof people can be tested simultaneously. Many useful techniqueshave been developed over the years to measure physical fitnessvery precisely. Although a full treatment of approaches to measurephysical fitness is beyond the scope of this text, it is important toknow that physical fitness, particularly aerobic fitness and muscularendurance, is frequently used to validate (or compare) measures ofphysical activity and exercise (see chapter 4 for more information).

The exercise sciences provide the basis for the academicdiscipline of kinesiology, which addresses the interrelationship ofphysiological processes and the anatomy of the body with respect tomovement. The study of kinesiology includes the major exercisesciences of exercise physiology, the movement sciences, and sportand exercise psychology, which have been used for the past 30years to promote the traditional exercise training model. Some of theother important exercise science areas of kinesiology you may haveread about are physical education, health education, anatomy,pedagogy, motor learning, motor control, biomechanics, nutrition,

sociology of sport, sport management, athletic training, physicaltherapy, and special populations.

Figure 2.2 shows how the traditional exercise training model hasbeen applied using the integration of major exercise sciences tomaximize performance. When concepts from these same exercisesciences are integrated with physical activity, they can also be usedto address public health policy goals.

The material presented in this chapter, when combined with thepublic health concepts discussed in chapter 1, represents aparadigm shift from primarily promoting exercise training andmaximal performance (the 1970s and 1980s model) towardpromoting physical activity for positive health outcomes (present-daymodel) as well. The integration of kinesiology concepts with publichealth outcomes is derived primarily from the two editions ofPhysical Activity Guidelines for Americans (USDHHS 2008, 2018)and the two editions of Physical Activity Guidelines AdvisoryCommittee Report (USDHHS, PAGAC 2008, 2018) and is covered inmore detail in part II of the text.

Figure 2.2   The traditional kinesiology-based exercise training model, whichpromotes the development of high levels of physical fitness, maximalperformance, or both. Exercise physiology, the movement sciences (e.g.,motor learning, motor control, motor development, motor behavior, andbiomechanics), and sport and exercise psychology have been the primaryintegrators (connectors) used by professionals to develop training programsthat yield positive outcomes.

KINESIOLOGY SUBDISCIPLINES AND EXERCISE TRAININGA complete review of the subdisciplines related to the field ofkinesiology is beyond the scope of this text. What follows is anoverview that focuses on the areas of exercise physiology, themovement sciences, and sport and exercise psychology. Theseprimary exercise sciences were chosen because they have been thecommon integrators for both traditional exercise training models andemerging public health physical activity models (see chapter 3 andpart II of the text for more).

Other important subdisciplines of kinesiology, such as nutritionand the sociology of sport (particularly as related to behavioralscience), should also contribute to the development of physicalactivity and exercise public health plans, but they are not a primaryfocus of this text. Nutrition public health goals and interventions havebeen covered extensively in other resources, such as the 2015-2020Dietary Guidelines for Americans, and you should become familiar

with these sources of information if you are not already. Behavioraland social methods for promoting physical activity and exercise arecovered in more detail in chapter 13.

How many calories would you expend playing golf for 18 holesand carrying your clubs the whole round?

EXERCISE PHYSIOLOGYAccording to Kenney, Wilmore, and Costill (2019), exercisephysiology is the study of how body structures and functions arealtered by acute bouts of exercise or physical activity, and how thebody adapts to the chronic stress of physical training. Exercisephysiology also addresses the integration and coordination of bodysystems needed to maintain homeostasis, including themusculoskeletal, nervous, circulatory, respiratory, immune, endocrine(hormone-producing), digestive, urinary, integumentary (skin), andreproductive systems. The findings from exercise physiology trainingstudies conducted since the 1960s were initially used for theprevention and treatment of chronic diseases such as cardiovasculardisease. Exercise physiology has now become a key discipline thathelps explain the role of physical activity and exercise in diseaseprevention and rehabilitation (see figure 2.3).

The study of exercise physiology evolved from a basic concept(i.e., exercise is medicine) promoted by the ancient Greeks andRomans such as Hippocrates and Galen and other physicians andscientists through time. Eventually, it developed into a complexdiscipline. Exercise physiology now addresses a spectrum of issuesranging from the molecular mechanisms associated with positivephysiological adaptations via physical activity and exercise all theway to developing and promoting public health policies that drive theconcepts presented in this text. The study of exercise physiology canbe applied to a variety of physical activity and exercise settings andresearch questions, including the following:

What type of exercise training program can increase maximaloxygen uptake (fitness) ( O2max) the most?How much exercise is needed for optimizing the benefits oftraining while minimizing the risk of injury?How much physical activity per week is required for goodhealth?How much physical activity or exercise is enough to maintain ahealthy weight?

Figure 2.3   Role of physical activity and exercise in chronic diseaseprevention and rehabilitation.Reprinted by permission A.L. Gibson, D.R. Wagner, and V.H. Heyward, Advanced FitnessAssessment and Exercise Prescription, 8th ed. (Champaign, IL: Human Kinetics, 2019), 3.

MOVEMENT SCIENCESThe movement sciences include the study areas of motor learning,motor control, and biomechanics. Motor learning is the study of howwe learn and perform motor skills such as cycling and dancing. Italso addresses the concepts that influence motor skills negatively orpositively. Motor control is the study of human informationprocessing and the integration of motor movements that involvemotor planning and execution. Motor development is the study ofchanges in motor behavior in a lifespan. The term motor behaviorcollectively includes the study areas of motor learning, motor control,and motor development. Biomechanics is the study of physicsapplied to the understanding of movement in living organisms.

Movement scientists often study movement efficiency byobserving movement patterns (through high-speed filming),measuring forces involved with movement, and developingequipment to maximize performance or protect participants frominjury due to excessive movement forces. They also study the impactof instructional information and feedback on skill development.

Information from the movement sciences can be applied to a varietyof physical activity and exercise settings and research questions,including the following:

How can we improve the efficiency or economy (i.e., reduce theenergy cost) of walking in individuals?How do fundamental motor skills affect physical activity behaviorand the development of physical fitness?What movement challenges are related to falls, and canphysical activity and exercise prevent falls?How does aging affect the biomechanics of walking and energyexpenditure?

The basic concepts of the movement sciences can help usunderstand factors such as the economy of physical movements,balance, and overall physical mobility. This understanding can helpin the planning of physical activity and exercise interventions forpopulations.

HEALTH AND FITNESS PROFESSIONSIn addition to the scholarly fields of kinesiology, otherprofessional subdisciplines have started to embrace thepromotion of physical activity as a primary missionrelated to their public health educational andrehabilitative initiatives. Fields such as healtheducation, physical education, athletic training, physicaltherapy, and sport management all contain information thatcan, and should, be applied to physical activity andexercise public health interventions. In fact, theintegration of the concepts from the subdisciplines ofkinesiology have led to employment opportunities via theNational Physical Activity Society (NPAS) and itscertification opportunities (see chapter 3 for more). TheNPAS was originally known as the National Society ofPhysical Activity Practitioners in Public Health (NSPAPPH)when it was established in 2006. The ability to translateresearch into effective clinical applications has become a

new requirement for many new job opportunities related tothe promotion of physical activity and public health.Specific competency areas set by the NPAS can be found atthe end of each chapter in the text.

SPORT AND EXERCISE PSYCHOLOGYSport and exercise psychology is the study of behaviors andoutcomes related to participation in sports or programs of exercisetraining. In sports, coaches are interested in sport psychology for avariety of reasons, including a desire to motivate their athletes tooptimize performance. Behavioral cues can help athletes focus onkey movement components to optimize their performance, and theycan learn how to use specific cues to mentally rehearse how to reactpositively.

Currently, researchers in physical activity and public health oftenapply behavioral models such as the transtheoretical model ofbehavioral change and the social cognitive model (see chapter 13) tounderstand and promote positive health behaviors in individuals. Thestudy of sport or behavioral psychology can be applied to a variety ofphysical activity and exercise settings and research questions,including the following:

What factors contribute to competition anxiety?What motivates people to become physically active?What motivates people to remain physically active for a lifetime?How does aging affect the motivation to participate in physicalactivity or exercise?How can we understand a population’s attitude toward andmotivation to participate in physical activity?

Understanding several sport and exercise psychology theories orstrategies is important for promoting behavioral change that canresult in the achievement of public health, physical activity, andexercise goals. In fact, the traditional foundations of sport and

exercise psychology have become part of what we will refer to as thebehavioral sciences for the remainder of the book.

Although the integration of the principles of kinesiology(particularly exercise physiology, the movement sciences, and thebehavioral sciences) have been used extensively in individualexercise training programs for maximal performance, they are alsoessential for effective physical activity and exercise promotion andplanning for populations. As you will learn in chapter 3 and part II ofthe text, kinesiology principles can be used to promote physicalactivity and exercise in the following lifestyle domains forpopulations: instrumental activities of daily living, household, leisure-time, occupational, and transportation (USDHHS, PAGAC 2018).

PRINCIPLES OF EXERCISE TRAINING, PRESCRIPTION, ANDPLANNINGNumerous principles of exercise training theory established inkinesiology literature are associated with the outcomes of optimizingperformance and improving physical fitness. Exercise training theoryhas provided the basis for individual exercise prescription since thelate 1970s. Therefore, an understanding of exercise training theory isneeded for developing physical activity and personalized exerciseplans. Participation in regular physical activity and exerciseprograms is essential for attaining basic functional health orphysical function (USDHHS, PAGAC 2018) both individually and inpopulations (this is covered in detail in chapter 7). A functionallyhealthy person has been defined as “a reasonably (not perfectly)healthy person [with] a lot of health but some disability” (USDHHS2008, p. G6-1) and includes the maintenance of functional ability androle ability. Measures of physical function include assessments of theability to walk (e.g., usually gait speed), run, climb stairs, carrygroceries, sweep the floor, stand up, and bathe (USDHHS 2018).

The following sections highlight general physical trainingprinciples and will help you integrate exercise science into long-termphysical activity and exercise plans.

TRAINING THEORY AND PRINCIPLESExercise training theory includes understanding how to useinformation from the exercise sciences (data-based outcomes fromthe research literature) and how to apply it effectively (the clinicalpractice of using training principles based on knowledge andexperiences) to improve performance.

The science of exercise prescription is often based on the FITTconcept; FITT stands for the frequency, intensity, time (duration),and type (mode) of exercise. The FITT concept can be furtherdescribed as follows:

Frequency: How often an exercise or physical activity isperformed. Frequency can be expressed in sessions, episodes,or bouts per week.Intensity: How hard one works, or the physical effort required toperform a physical activity or exercise. Intensity can be providedin absolute or relative terms such as low, moderate, or vigorous(see the discussion of intensity later in this chapter).Time: The amount of time in which a physical activity or exerciseis performed. Duration is usually expressed in minutes.Type: The specific mode of physical activity or exercise.

A variety of factors or principles of training should be consideredin order to realize adaptations. Traditional concepts of training theorywere originally applied to individuals but are also pertinent tophysical activity or exercise interventions for populations. Followingare descriptions of the principles of training (labels and descriptionsmay vary by reference sources you use):

Practical goal setting: Determining the needs and goals of anindividual or population.Genetics and individual variation: The genetics and potential forchange of an individual or population with training.

Motivation: Evaluation of the drive or personal motivation of anindividual or population and the need to provide appropriatefeedback and reinforcement for success with physical activityprogramming.Teaching model: The need to teach individuals or populationshow to participate effectively in physical activity or exercise toimprove performance while reducing the risk of injuries.Fitness evaluation: Evaluating physical abilities to participateeffectively in physical activity and exercise based on issuessuch as age, health status, and experience.Overload: Changing the FITT variables of a plan to improvephysiological, movement, and psychological adaptations.Specificity: The specific physiological, movement, andpsychological adaptations that occur as a result of the specificdemands applied.Modifications: Adjusting the physical activity or exercise regimenbased on factors such as disease, injury, and change inmedications.Progression/Adaptation: An overall physical training plan thatincludes cycles of varying training volumes based on seasonalvariations that provide appropriate rest and recovery periods.Overtraining: Participating in too much physical activity orexercise, which can result in negative physical performance; ifcontinued, overtraining can produce negative psychologicaleffects and increase the risk of musculoskeletal injury.Detraining: Discontinuing physical activity or exercise, and therate and magnitude at which training benefits are lost.Recovery: How a person recovers from participating in aprogram of physical activity or exercise and the strategies thatmight help improve recovery time.Compliance: Why or how an individual or population continuesto participate in or drops out of a physical activity or exerciseprogram.

VOLUME AND DOSE RESPONSEThe concept of total caloric expenditure is directly related to thevolume, or dose, of training (physical activity or exercise) thataccumulates over time. Daily voluntary caloric expenditure canaccount for 15 to 30% of a person’s total caloric expenditure. Manyof the benefits of physical activity and exercise training are related tothe amount of caloric expenditure achieved, which is why it shouldbe considered when developing exercise prescriptions and publichealth, physical activity, or exercise plans. (Energy, or caloric,balance is described in detail in chapter 6.)

Essentially, when you are physically active, you expend morekilocalories (or kcals) than when you are sedentary. For example, anaverage person (approximately 70 kg, or 154 lb) expends about 1.2kcals per minute while sitting at rest. Another common metabolicmeasure is the metabolic equivalent, or MET; 1 MET (3.5 ml . kg–1 .min–1) is equal to the resting energy expenditure for the sameaverage person. It is also important to understand the differencebetween gross and net energy expenditure, because both are usedby practitioners to measure or estimate total caloric expenditure.Gross energy expenditure (e.g., in METs) combines physicalactivity or exercise energy requirements with resting energyexpenditure, whereas net energy expenditure reflects just thephysical activity or exercise energy requirement.

INTEGRATING THE TRADITIONAL EXERCISE SCIENCEPRESCRIPTION INTO PERSONALIZED ANDPOPULATION EXERCISE PLANSProfessional organizations and associations such as theAmerican College of Sports Medicine (ACSM) have beenpromoting traditional exercise science methods fordeveloping individualized exercise prescriptions since the1970s. Although these traditional exercise prescriptionmethodologies can be useful for promoting physical

activity and exercise to the public, many people may findthem too complex and difficult to comply with. This may beespecially true for people and groups who are interestedonly in improving or maintaining their health and fitness,

and not in performance outcomes. The Physical ActivityGuidelines for Americans (USDHHS 2008, 2018) weredeveloped with real-life examples of children,adolescents, adults, and older adults who have become andremained physically active.

Given the large prevalence of inactive peopleworldwide, it is important to become familiar with the

cases presented in the Physical Activity Guidelines forAmericans (e.g., Harold, Maria, Douglas, Jake, Ebony, andRumi). Understanding the individual and populationstrategies for the cases described in that report andlearning how to integrate the physical training conceptspresented in this chapter will help optimize success inphysical activity promotion.

Figure 2.4   Physical activity, exercise, and health outcomes.

The volume, or dose, is the amount of physical activity or exerciseperformed and is based on frequency, duration, and intensity.Accumulation refers to acquiring a specific dose of physical activityor exercise, or achieving a physical activity or exercise goal, bycombining several shorter bouts (e.g., three bouts lasting 10 minuteseach to achieve 30 minutes of daily physical activity or exercise).

Dose-response refers to the amount of physical activity orexercise needed for achieving health, fitness, or performance goals.Dose-responses can be measured in terms of the frequency,duration, and intensity of physical activity or exercise or the totalvolume of work. Dose-responses related to physical activity orexercise are similar to those related to medications, in thatresponses vary with the dose of medication. Figure 2.4 shows someof the dose-response curves for physical activity or exercise inrelationship to various health outcomes.

TYPEWhen considering the FITT variables for exercise prescriptions orphysical activity and exercise plans, most exercise professionalsrecommend selecting the type of physical activity or exercise first,based on a practical goal-setting process for either individuals orpopulations.

The type (or mode) of physical activity or exercise can becategorized as anaerobic, aerobic, or combined, and as either staticor dynamic. According to the Physical Activity Guidelines forAmericans (USDHHS 2008, 2018), anaerobic activities require theuse of nonoxidative energy systems (energy-producing reactions inthe body that do not require oxygen) and engaging in these activitiescan improve the capacity of these systems and increase thetolerance of acid–base imbalance during high-intensity exercise,which allows one to work more effectively at high intensities for shortdurations. Examples of anaerobic activities that are also bone-strengthening activities are 100-meter sprints, gymnastics, andresistance training (e.g., weight training to increase mass andimprove strength, power, and endurance). Aerobic activities requirethe use of large oxidative systems (i.e., heart and lungs) andimprove cardiorespiratory endurance. Examples of aerobic activitiesare walking, cycling for 30 minutes, jogging, and rowing.

Combined physical movements take place in sports such assoccer, tennis, and racquetball that require significant contributions

of energy from both anaerobic and aerobic energy sources. Someexamples of combined physical movements are the bouts of physicalactivity or exercise that involve high intensity interval training(HIIT), which requires working at a higher intensity for a few secondsor minutes followed by working at lower (recovery) intensities for thesame amount of time. Interval training can be used for eitherimproving health or maximizing performance.

Static physical activity or exercise (or isometric physical activityor exercise) is anaerobic and requires an increase in forceproduction with limited range of motion (ROM); a test of handgripstrength is an example. Dynamic physical activity or exerciserequires muscle-shortening (concentric) and muscle-lengtheningmovements (eccentric). Dynamic physical activities involve greaterROM than static activities and are usually rhythmic and morecontinuous. Regular engagement in static and dynamic physicalactivities is associated with higher flexibility and balance outcomes.

Physical activity and exercise can be further categorized ascreating specific physiological demands for energy based onintensity and duration. Anaerobic power (or peak power) activitiesinvolve short-burst, high-intensity movements that last less than 15seconds and stress the anaerobic energy pathways of the body.Anaerobic power abilities are highly related to genetics and thenumber of fast-twitch muscle fibers a person can recruit. Fast-twitchfibers are recruited primarily with higher work intensities and quicklyfatigue, while slow-twitch fibers are primarily recruited at low tomoderate work intensities and are fatigue resistant. Anaerobiccapacity (also known as mean anaerobic power or peak anaerobicpower) activities also involve short-burst, high-intensity movements,but they last from 15 seconds up to 3 minutes. Anaerobic capacityactivities produce high levels of metabolic products such as lacticacid, and challenge the person’s tolerance of an acid–baseimbalance.

Aerobic power activities require high levels of oxygen delivery tothe working muscles and last from 3 to 15 minutes. Aerobic power is

associated with the measurement or estimation of maximal oxygenuptake ( O2max), which is the maximal ability of the body to useoxygen to produce energy for performing work. Figure 2.5 illustratesthe concept of exercise intensity (running) and O2max for a trainedand an untrained man. Aerobic capacity activities stress the abilityto maintain high percentages of O2max for extended periods of time(e.g., 20 minutes or longer). An average untrained person should beable to work for this amount of time at about 50% of O2max aerobiccapacity prior to a program of physical activity or exercise, but canincrease this to 70% (or higher) after several weeks. Improvementsin aerobic capacity can improve cardiorespiratory economy (i.e.,energy or oxygen cost at a given workload or speed) by recruitingless muscle mass to perform the same amount of work.

Figure 2.5   Relationship between exercise intensity (running speed) and O2max for a trained and an untrained man.Reprinted by permission from L. Kenney, J. Wilmore, and D. Costill, Physiology of Sport andExercise, 7th ed. (Champaign, IL: Human Kinetics, 2020), 130.

INTENSITYIntensity can be determined for a physical activity or exercise in avariety of ways based on whether the activity is more aerobic ormore anaerobic. For example, a person can obviously work at ahigher intensity for a shorter period of time (e.g., a few seconds) thanfor several minutes. Intensity is the primary FITT variable that affectsthe total caloric expenditure of physical activity or exercise when theduration is held constant. Intensity level also affects the risk of injuryif it is set too high for the current level of conditioning of an individualor a population.

Intensities can be classified as light, moderate, or vigorous, andas absolute or relative. The Physical Activity Guidelines AdvisoryCommittee Report (USDHHS, PAGAC 2008, 2018) generallyclassifies physical activity or exercise as light intensity whenactivity requires 1.6 to less than 3.0 METs, such as walking at a slowpace (<2 mph [<3.2 km/h]) or cooking activities. An activity orexercise is of moderate intensity when one is working between 3and 6 METs, and an activity is considered vigorous intensity whenthe person is working above 6 METs. Absolute intensity can beexpressed in kcals/min, in METs, or as walking at 4 miles per hour(6.4 km/h) or jogging at 5 miles per hour (8 km/h). For resistanceexercise, absolute intensity can be expressed as the amount ofweight lifted or force exerted (e.g., in pounds or kilograms). Absoluteintensity may also be classified into categories such as low,moderate, vigorous, and maximal. Table 2.1 shows the classificationof physical activity levels from the Physical Activity Guidelines forAmericans (USDHHS 2008).

Relative intensity is usually expressed as a percentage ofaerobic power ( O2max) or as a percentage of measured heart rateor heart rate reserve (maximal heart rate − resting heart rate).Perceived exertion ratings (i.e., how hard people feel they areworking, from light to very hard) can also be used as a relativeintensity measure along with a percentage of 1-repetition maximum

(i.e., the maximum a person can lift in one trial) for weightliftingactivities.

The Physical Activity Guidelines Advisory Committee Report(USDHHS, PAGAC 2008, pp. D-3, D-4, Table D-1) containsclassifications of physical activity and exercise intensities that showhow the intensity of physical activity and exercise is significantlyaffected by the differences of O2max of individuals or populations.As shown in figure 2.6, an adult with a higher-than-average O2maxof 14 METs who is walking at 3 miles per hour (4.8 km/h) is workingat a relative intensity of 24% of her max (low). However, an adultwith a low O2max of 6 METs is working at a relative intensity of 55%of his max (hard). An adult with a low aerobic capacity of 4 METscannot walk at 4 miles per hour (6.4 km/h) for very long because theintensity exceeds O2max and the activity becomes mostlyanaerobic; this workload requires at least a 5 MET absolute intensity.

A full discussion of the many ways to determine physical activityand exercise intensities is beyond the scope of this text. However,the common aerobic and anaerobic methods used for determiningintensity for exercise prescriptions, which also apply to physicalactivity and exercise interventions for populations, are discussednext.

Table 2.1   Classification of Total Weekly Amounts of AerobicPhysical Activity Into Four Categories

Level ofphysicalactivity

Range ofmoderate-intensityminutes perweek

Summary ofoverallhealthbenefits Comment

Inactive No activitybeyond baseline

None Being inactive is unhealthy.

Low Activity beyondbaseline butfewer than 150minutes a week

Some Low levels of activity are clearlypreferable to an inactive lifestyle.

Medium 150 minutes to300 minutes aweek

Substantial Activity at the high end of thisrange has additional and moreextensive health benefits thanactivity at the low end.

High More than 300minutes a week

Additional Current science does not allowresearchers to identify an upperlimit of activity above which thereare no additional health benefits.

Reprinted from USDHH, PAGA (2008).

PERCENTAGE OF MAXIMAL HEART RATEThe percentage of maximal heart rate (MHR) method is an aerobicmethod based on the simple exercise physiology assumption thatpredicted MHR is equal to 220 minus age (generally the error is plusor minus 10 beats per minute, or bpm). You then multiply MHR bythe percentage of the intensity desired. For example, if a goal is tohave a 30-year-old man work at 60 to 80% of his MHR, thecalculation would be as follows: 220 − 30 = 190 × 0.6 and 190 × 0.8,or an exercise heart rate between 114 bpm and 152 bpm. Thismethod is convenient to use with beginners who may be at higherhealth risk, because it is conservative (when using lowerpercentages) and yields lower intensities than some other methodsdo.

Figure 2.6   Relative intensity of walking at 3 mph (4.8 km/h, 3.3 METs) and4 mph (6.4 km/h, 5.0 METs) expressed as a percentage of O2max for adultswith an exercise capacity ranging from 4 to 14 METs.Reprinted from USDHH, PAGA (2008).

PERCENTAGE OF MAXIMAL HEART RATE RESERVE, OR TARGETHEART RATEThe percentage of MHR reserve, or target heart rate (THR), methodis an aerobic method also based on simple MHR prediction; itinvolves subtracting resting heart rate (RHR) according to thefollowing equation:

MHR reserve = MHR − RHR

THR = (MHR − RHR) × (desired percentage of intensity, e.g. 60%)+ RHR

A 40-year-old with an RHR of 80 who works at 60 to 70% of MHRreserve would yield the following equation: THR = (180 − 80) × 0.6 +80 = 140 bpm and THR = (180 − 80) × 0.7 + 80 = 150 bpm for aTHR range of 140 to 150 bpm. This formula is called the Karvonenformula in honor of the exercise physiologist who first described it inthe late 1950s. This method is often used for those who are familiarwith regular exercise and at low health risk, because it provideshigher intensities than a simple percentage of MHR.

METABOLIC EQUIVALENTSThe metabolic equivalent (MET) aerobic method is based on theconcept described earlier in this chapter that, for healthy adults, 1MET = 3.5 ml . kg–1 . min–1. As you have learned, physical activity andexercise can be classified as light, moderate, or vigorous intensitybased on the MET level required to perform specific movements.The Physical Activity Guidelines Advisory Committee Report has alisting of activities and exercises that require at least 6 METs’ worthof intensity (USDHHS, PAGAC 2008, pp.D-5, D-6).

Once the O2max of an individual or a population is measured(usually on a maximal exercise test) or estimated (see chapter 5 formore on measuring or estimating O2max), it can be expressed inMETs. A percentage of the maximal METs achieved can then beused to calculate an initial or follow-up exercise training intensity. Aperson with a O2max of 12 METs might train at 50% of hismaximum, or at 6 METs. Physical activity practitioners commonlyuse this method to help people train at a certain intensity.

Scientific studies show us that it is never too late to begin aphysical activity program. What are some reasons that physicalactivity is important throughout life?

PERCENTAGE OF MAXIMAL OXYGEN UPTAKE

As with the MET determination just discussed, if you know theindividual’s or population’s maximal oxygen uptake ( O2max), youcan calculate an intensity for physical activity or exercise based on apercentage of that max. For example, if the goal is to train a group at70% of O2max, and the group’s average O2max is 35 ml . kg–1 .min–1 (or 10 METs), you would use the calculation 35 ml . kg–1 . min–1× 0.7 = 24.5 ml . kg–1 . min–1 (or 7 METs). Figure 2.7 illustrates how touse the linear relationship between heart rate (HR) and O2max todetermine a representative physical activity or exercise HR response(75% of O2max) based on the percentage of O2max prescribed.This method is still one of the most popular methods used byexercise physiologists to determine exercise intensities.

KILOCALORIES PER MINUTE OR PER HOURThe kilocalories per minute or kilocalories per hour aerobic methodhas become one of the most popular methods to determine physicalactivity and exercise intensity, particularly in weight loss and weightmaintenance programs. The conversion factor, 1 liter of oxygenconsumed being equal to ~5 kcals/min, is used to determine the totalkcals expended for a bout of physical activity or exercise. Forexample, if someone weighs 80 kilograms (176 lb) and is working at35 ml . kg–1 . min–1 (or 10 METs), you could calculate caloricexpenditure as follows:

35 ml . kg–1 . min–1 × weight [in kg] × 1,000 = oxygen uptake inliters/min, or 35 × 80 / 1,000 = 2.8 liters/min.

Then, converting to kcals/min, you would have 2.8 liters/min × ~5kcals/min, or 14 kcals/min, or 840 kcals/h (14 × 60).

Figure 2.7   Linear relationship between HR and O2max with increasing ratesof work and the HR equivalent to a set percentage (75%) of O2max.Reprinted by permission from L. Kenney, J. Wilmore, and D. Costill, Physiology of Sport andExercise, 7th ed. (Champaign, IL: Human Kinetics, 2020), 203.

PERCEIVED EXERTION SCALES AND THE TALK TESTThe perceived exertion (PE) scale and talk test methods require thatpeople evaluate how hard they are working, or determine whetherthey can carry on a conversation at a given intensity of work. Figure2.8 shows a PE scale called the OMNI-Walk/Run Scale for adults; itis a simple way for practitioners to teach people how to rate theirphysical activity and exercise intensity. For example, an OMNI scale

rating of 7 for an untrained adult would indicate that the person isworking “somewhat hard” to “hard.” Scales such as the OMNI scalecan be used to help people focus on achieving moderate to vigorousphysical activity or exercise intensities by achieving PE levels ≥4(PEs of 4 to 6 = moderate physical activity or exercise, and PE > 6 =vigorous physical activity or exercise). The talk test basically tellspractitioners whether someone is working at a comfortable level (i.e.,can carry on a conversation easily) or struggling (i.e., cannot carryon a conversation comfortably).

PE scales and the talk test are very practical because people candescribe their feelings about their bodily responses to physicalactivity or exercise (e.g., breathing, muscle pain, sweating).However, they are complicated by various physiological factors thatinfluence the ratings such as lactate and ventilatory thresholds (seeACSM 2018 for more on the lactate and ventilatory thresholds).Exercise practitioners should make sure that the people using thesemethods have experience with them. Those who don’t (especiallyyouth) often underestimate how hard they are working.

REPETITION MAXIMUMThe most commonly used anaerobic method related to weightliftingas a resistance training mode is the 1-repetition maximum (1RM).For example, a person who can lift 100 pounds (45.5 kg) over hishead one time and no more has a 1RM of 100 pounds. This wouldbe called his absolute strength for that lift. Relative strength wouldreflect his 1RM divided by his body weight as stated in the PhysicalActivity Guidelines Advisory Committee Report (USDHHS, PAGAC2008, Table D-1) as discussed earlier.

Figure 2.8   OMNI-Walk/Run Scale of perceived exertion for adults.Reprinted by permission from R.J. Robertson, Perceived Exertion for Practitioners: RatingEffort With the OMNI Picture System (Champaign, IL: Human Kinetics, 2004), 142

Because performing a 1RM can be challenging for inexperiencedweightlifters or older adults, many practitioners have the personperform a 5RM (maximum amount of weight lifted five times) or10RM (maximum amount of weight lifted 10 times), which is saferand more comfortable. Normative standards are available for 1RMby age and sex (see ACSM 2018), which can be used for resistanceperformance evaluations of individuals or populations. In addition,values from 5RM and 10RM can be used to predict 1RM abilities,which can then be used to develop exercise prescriptions or physicalactivity or exercise plans.

WORKLOADThe workload anaerobic method considers factors that affectresistance exercise such as speed, muscular strength, muscularendurance, power, and the specific muscle groups involved. Severalresources (e.g., ACSM 2018) detail the specifics of resistancetraining programs for various individuals and populations. However,all resistance training regimens should consider the following:emphasis (e.g., strength or muscular endurance); participant’s level(e.g., beginner versus advanced); percentage of 1RM, 5RM, or10RM; number of sets and number of repetitions per set (e.g., 10

repetitions per set, for three sets); velocity of movement (e.g., slow,moderate, or fast); rest between sets (see the following discussion oftime); and the frequency of participation per week (see the followingdiscussion of frequency).

TIMETable 2.2 provides some general recommendations based ontraditional exercise prescription programming for determining thetime (duration) of types of physical activity and exercise activities.The table includes recommendations for achieving basic functionalhealth (a minimal long-term goal) as well as high performance.

FREQUENCYTable 2.3 provides some general recommendations for the frequencyof types of physical activity and exercise activities. It includesrecommendations for achieving basic functional health (a minimallong-term goal) as well as high performance.

Table 2.2   General Recommendations for Time for AchievingFunctional Health or High Performance

Type of activityFunctional health/physicalfunction High performance

Aerobic 20-60 min 20-120 min

Anaerobic 20-30 min 20-120 min

Aerobic andanaerobic

Based on practical goalsetting

Based on practical goalsetting

Recommendations can be achieved continuously or accumulated in multiple bouts per day.

Table 2.3   General Recommendations for Frequency for AchievingFunctional Health or High Performance

Type of activityFunctional health/physicalfunction High performance

Aerobic 3-5 days/week 5-7 days/week

Anaerobic 2-3 days/week 3-4 days/week

Aerobic andanaerobic

Based on practical goalsetting

Based on practical goalsetting

Recommendations can be achieved continuously or accumulated in multiple bouts per day.

APPLYING PHYSICAL ACTIVITY AND EXERCISE TRAININGPRINCIPLESOnce you are comfortable using the FITT concept, it would behelpful to learn how to apply exercise science principles and practicethem to improve the exercise training adaptations of individuals andpopulations. The exercise principles previously defined are explainedin more detail in this section.

PRACTICAL GOAL SETTINGWhen determining the needs and goals of an individual or group, aneeds assessment should be conducted that includes practical andachievable goals for physical activity and exercise. Use the conceptsand strategies of behavioral science theoretical models described inchapter 13 to fine-tune your goal-setting skills. A good goal for agroup would be to achieve the minimal recommendations of thePhysical Activity Guidelines for Americans (USDHHS 2008, 2018).

GENETICS AND INDIVIDUAL VARIATIONThe genetics of an individual or a population can affect the ability tobenefit from physical activity and exercise. Genetics also accountsfor adaptation rates and the maximal potential for adaptations.Obviously, there are variations for levels of change within individualsand populations for important health fitness variables similar to the

variance in the curves such as that for physical activity, exercise, andhealth outcomes previously shown in figure 2.4.

Figure 2.9 shows five genetic and training variations that youmight see in relationship to the benefits of physical activity orexercise training over time (e.g., six months). Curve 3 represents aprofile of adaptation to physical activity and exercise that mostpractitioners expect to see; however, many people do not respond inthis fashion. You will need to evaluate your physical activity andexercise plans regularly to adjust them to facilitate further gains inhealth outcomes.

CASE STUDY

TOTAL PHYSICAL ACTIVITY PER WEEKThe amount of physical activity and exercise performedfor a given period of time (see USDHHS, PAGAC 2008,section D, for more) can be determined by using theabsolute intensity, the time or duration, and thefrequency. As shown in table 2.4, the dose of physicalactivity and exercise can be expressed in minutes orhours per week (of moderate-intensity, vigorous-intensity, or moderate- plus vigorous-intensityactivity), or in terms of distance walked, jogged, orrun per day or week. The amount of physical activity andexercise can also be expressed in kilocalories per dayor week, kilocalories per kilogram of body weight perday or week, or MET-minutes or MET-hours per day orweek. By using the concept of relative intensity, timeor duration, and frequency (e.g., 30 minutes at 70% ofpredicted MHR five times per week for 24 weeks), one cancompare and generalize across various FITT amounts todetermine recommendations for physical activity andexercise in population interventions.

Table 2.4 shows that if Albert participated inphysical activity (walking at 3 mph, or 4.8 km/h, atmoderate intensity) for 2.5 hours per week (a minimumrecommendation), he would average 495 MET-minutes perweek, 8.25 MET-hours per week, or the equivalent of 7.5miles (12 km) per week. If Albert weighed 165 pounds (75kg), his energy expenditure would be 620 kcals per week.If Albert were active at the same intensity for 5 hoursper week, he would average 990 MET-minutes per week,16.5 MET-hours per week, or the equivalent of 15 miles(24 km) per week, and his energy expenditure would be1,240 kcals per week.

If Albert in the preceding example were able toparticipate in physical activity or exercise at avigorous intensity such as jogging at 7 miles per hour(11 km/h) for 2.5 hours per week, he would expendconsiderably more calories per week (620 kcals versus2,155 kcals based on gross energy expenditure values),which reinforces the importance of intensity whendetermining FITT variables and setting goals forindividuals and populations.

MOTIVATION

Motivation refers to the importance of the behavioral reinforcementof intrinsic motivation goals that promote regular participation inphysical activity or exercise. Chapter 13 describes behavioralmodels practitioners commonly use to encourage and maintainmotivation levels.

Figure 2.9   Training adaptation curves for five individuals.

TEACHING MODELThe teaching model refers to the need for practitioners to beeffective teachers who use educational strategies or logic models(see chapter 15 for more about logic models) to motivate targetpopulations and reinforce the benefits of physical activity andexercise. Figure 2.10 provides an example of a simple teachingmodel a practitioner can use to work with an individual or populationto minimize barriers that might negatively affect the adoption ofregular physical activity. Practitioners also can work to maximizethose factors for specific goals and outcomes that positively promote

the adoption of regular physical activity and exercise along thephysical activity and exercise continuum.

Figure 2.10    Factors influencing an individual to adopt regular low to highlevels of physical activity and exercise.

FITNESS EVALUATIONEvaluating fitness levels prior to initiating physical activity andexercise programs is valuable for determining the effectiveness ofthe programs. The level of evaluation required will vary greatlydepending on the physical abilities of the target population and itsgoals and needs. Performing fitness evaluations in conjunction withdetermining goals will help ensure that the program meets the needsof the target population.

OVERLOADThe overload principle refers to the fact that improvements inhealth and physical fitness are directly related to increases in FITTvariables by gradually increasing the physical stress on the body.Changes in overload should be considered in conjunction withgenetics and individual variation to ensure that people have adapted

to current training levels before changing any FITT variables. Toolittle or too much change in progressive overload will not produce thedesired results. In most cases, changing all the FITT variables atonce is unwise, because people do not have enough time to adjustto new workloads, which can result in injury or burnout. Applying theoverload principle correctly requires a lot of experience because ofthe great variability of physical adaptations to physical activity andexercise in individuals and populations.

SPECIFICITYThe specificity principle refers to the fact that changes in healthand fitness depend on adjusting FITT variables for the desiredadaptations. Whether working with individuals or populations, it isimportant to consider the specific physical demands of the physicalactivity or exercise plan. For example, a plan designed to helpsedentary, high-health-risk middle-aged men reach minimal levels offunctional fitness would be significantly different from one designedto help young, experienced adult women runners train to complete amarathon. The two goals are obviously very different and wouldrequire very different manipulation of FITT variables to achievesuccess.

MODIFICATIONSExercise prescriptions and physical activity and exercise plans oftenneed to be modified based on individual, population, andenvironmental changes. Variables that may require a modification ofa physical activity or exercise plan include injury, illness,medications, lack of recovery, and symptoms of overtraining. Amodification might involve changing FITT variables to allow a personor population to continue with the plan, but at adjusted levels; thiscan minimize the risk of complete relapse (stopping and not startingagain). Learning how to modify physical activity and exercise planswill encourage compliance (see the discussion of compliance formore).

PROGRESSION/ADAPTATIONProgression/adaptation refers to cycling (or varying) the FITTvariables, volume of physical activity and exercise, and recoverytime. Figure 2.11 illustrates a simple progression/adaptation curvethat shows adaptation and progression of health and fitnessoutcomes over 30 weeks of participation. Progression andadaptation improvements depend on the starting health or fitnesslevels of the person or population (usually, the lower the startinghealth or fitness level, the greater the initial gains). Normalprogression/adaptation curves include an initial stage, a plateaustage, and an improvement stage.

Figure 2.11   Simple progression/adaptation example.

Training plateaus are periods when little, if any, improvement infitness occurs. The rate of improvement can be influenced byeffective progression/adaptation of training. It is important to be ableto recognize the plateau phenomenon and use effective behavioral

(see chapter 13 for more information) and FITT strategies to helppeople remain motivated to maintain or increase their physicalactivity and exercise behaviors. This is because lack of improvementmay promote relapse. There are numerous ways to apply theprogression/adaptation principle to physical activity and exerciseplans; the references at the end of the chapter and the e-media linksin the web resource offer more information about FITT variables andseasonal variations associated with progression/adaptation.

OVERTRAININGOvertraining can produce abnormal physical and psychologicalresponses. It is defined as doing too much physical activity orexercise without taking the time to recover appropriately.Overtraining is associated with increased overuse injuries (muscleand skeletal problems) and addictive behaviors that are directlyrelated to relapses and lower exercise compliance levels. Symptomsof overtraining include excessive fatigue, unusual muscle soreness,a lower immune response (high incidence of upper respiratoryinfections), insomnia, weight loss, increased resting heart rates, andfeeling mentally burnt out.

Chronic overtraining that occurs over several weeks or monthscan lead to burnout and is often associated with permanent physicalactivity or exercise relapses. You can help individuals or populationsavoid overtraining by encouraging them to recognize the signs ofaddiction to exercise (e.g., the notion that if a little bit is good, moreis better) and to take a short break (two or three days) in theirphysical activity or exercise routine if such signs are evident.

DETRAININGDetraining refers to the loss of health or fitness following thecessation of a regular program of physical activity or exercise. Healthand fitness benefits often decrease at rates similar to those at whichthey accrued; however, significant variability can occur betweenspecific factors (e.g., osteoporosis benefits versus functional health

benefits; see figure 2.4). Significant detraining does not occur in aday or two, but people who stop all regular physical activity orexercise for two weeks to a month will notice losses in their aerobicand anaerobic abilities.

Bed rest is an extreme example of detraining. Dr. Jere Mitchelland his colleagues from Southwestern Medical School in Dallas,Texas (McGuire et al. 2001), reported in a classic study that 20 daysof complete bed rest in 20-year-old males caused a greaterdeterioration in physical cardiorespiratory capacity than did 30 yearsof aging. Some research suggests that detraining effects can beminimized by continuing to be physically active even at a reducedvolume of training before resuming a regular schedule ofparticipation.

RECOVERYThe rate at which people or populations can recover is influenced byFITT variables, age, past experience with physical activity andexercise, environmental factors such as heat and altitude, averageamount of sleep, and the abilities to rehydrate and consume enoughenergy to meet physical activity and exercise demands. Generally, atleast 24 hours are needed to properly recover from high-intensityexercise, especially if someone is active daily. People who are justtrying to meet the minimum guidelines for moderate and vigorousphysical activity of 2.5 hours per week should not have much troublerecovering unless they have existing musculoskeletal injuries,disabilities, or complicating medical conditions.

COMPLIANCECompliance refers to people’s ability to continue to participate inregular physical activity or exercise programming. Following arebarriers that can negatively affect compliance:

Lack of timeLow potential for physical adaptations

Poor mobilityUnrealistic physical activity or exercise goals or expectationsLack of knowledge about physical activity and exerciseLow perceived competency with physical activityInjuryPast negative experiences with physical activity or exercise

LEADER PROFILEHo Han, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?My initial research interests in exercise science andhealth behavior began my senior year at Korea NationalSport University in South Korea. During my undergraduateyears, I specialized in taekwondo, a traditional Koreanmartial art, and was excited to study exercise andmetabolic responses in humans. Professor Bongan Kwonencouraged me to study abroad in the United States, and Iwent to graduate school for my master’s degree in exercisephysiology at the University of Texas at Austin. Duringthe program, my academic advisor, Dr. John L. Ivy,suggested I take a graduate course taught by two highlyrenowned professors in the fields of exercise physiology(Dr. John L. Ivy) and epidemiology (Dr. Harold W. Kohl).In this class, I realized for the first time that a lackof physical activity was an epidemiologic issue that had

to be addressed more seriously at the population level. Inorder to learn more about physical activity in publichealth, I shifted my major to the health behavior andhealth education doctoral program under the supervision ofDr. Kohl. In the doctoral program, I learned a great dealabout physical activity epidemiology and variousstrategies to increase physical activity including theory-based intervention programs, community-wide campaigns, andthe built environment. This academic background influencedmy current career in teaching and research at OklahomaState University.

Did any one person have a major influence on your career?How?A number of mentors and advisors have had an influence onmy career, but one primary influence was Dr. Harold W.Kohl. My past and current research interests in physicalactivity and public health developed and continued aftermeeting Dr. Kohl. As an international scholar, I facedmany challenges during my academic years, especially dueto the language barrier. It was quite difficult for me toadapt to a new field of physical activity and publichealth using a foreign language. He showed enduringpatience and provided concrete research and academicresources that guided me to become a successful,independent researcher. I will be endlessly grateful toDr. Kohl for his efforts and guidance.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?My overall research interests are physical activitymeasurement and community-wide interventions to increasephysical activity levels. One of my current researchprojects is to learn how to develop a clear and effectivephysical activity prescription using a step-based metricto help more people achieve the recommended amount ofphysical activity and, in turn, improve their quality oflife. I am also very interested in the various healthoutcomes associated with physical activity for the purposeof disease prevention, treatment, and rehabilitation.

Why do you do what you do?

Despite the substantial health impact of physical activityon all-cause mortality and cardiovascular diseasemortality, physical inactivity is now described as apandemic—a leading cause of death in the world. One of thebest ways to increase individual physical activity levelsmay be to provide a physical activity prescription that ismore understandable and easier to follow compared to theones currently available. All of the efforts on my currentprojects are to facilitate the translation of researchfindings into real-life situations.

What are two key issues that must be addressed by 2030?As the independent health risks of a sedentary behaviorlifestyle have become a well-known issue in public health,an effort to reduce sedentary behavior has to occur whilesimultaneously promoting physical activity (e.g., teachingbehavior replacement skills or developing a guideline forsedentary behavior). In addition, more effectivepopulation-wide interventions need to be implemented.Technology-based interventions for providing feedback,coaching and goal-setting, and social networking could bea great option.

Although compliance is presented as the last trainingconsideration, it is one of the most important because, without it,even the best physical activity or exercise plan will fail. By minimizingbarriers to compliance the opportunities for developing successfulphysical activity and exercise plans are significantly enhanced.

HEALTH AND FITNESS BENEFITS OF PHYSICAL ACTIVITYAND EXERCISENumerous health, fitness, and performance benefits of physicalactivity and exercise have been reported in the scientific literature. Acomplete list is beyond the scope of this chapter, but some specificsare provided in part II of the text. Some of the general benefitsgleaned from the Physical Activity Guidelines for Americans(USDHHS 2018) are provided in the sidebar Health BenefitsAssociated With Regular Physical Activity.

As noted in the Physical Activity Guidelines Advisory CommitteeReport (USDHHS, PAGAC 2008, 2018), people who are interestedin training programs to increase performance-related fitness (e.g.,agility, balance, coordination, speed, power, and reaction time)should seek advice from professionals specializing in sport skillactivities, because people with these interests are already moreactive than the guidelines recommend for health and fitness. Peoplewho are interested in performance-related fitness may also be athigher risk for injury related to physical activity and exercise, and assuch should consider factors that will help them remain safe andactive (see chapter 10 for more information).

HEALTH BENEFITS ASSOCIATED WITH REGULARPHYSICAL ACTIVITYChildren and Adolescents

Strong Evidence

Improved cardiorespiratory and muscular fitness

Improved bone health

Improved cardiovascular and metabolic health

biomarkers

Favorable body composition

Moderate Evidence

Reduced symptoms of depression

Adults and Older Adults

Strong Evidence

Lower risk of early death

Lower risk of coronary heart disease

Lower risk of stroke

Lower risk of high blood pressure

Lower risk of adverse blood lipid profile

Lower risk of type 2 diabetes

Lower risk of metabolic syndrome

Lower risk of colon cancer

Lower risk of breast cancer

Prevention of weight gain

Weight loss, particularly when combined with reduced

calorie intake

Improved cardiorespiratory and muscular fitness

Prevention of falls

Reduced depression

Better cognitive function (for older adults)

Moderate to Strong Evidence

Better functional health (for older adults)

Reduced abdominal obesity

Moderate Evidence

Lower risk of hip fracture

Lower risk of lung cancer

Lower risk of endometrial cancer

Weight maintenance after weight loss

Increased bone density

Improved sleep quality

Note: The Advisory Committee rated the evidence of healthbenefits of physical activity as strong, moderate, orweak. To do so, the Committee considered the type, number,and quality of studies available, as well as consistencyof findings across studies that addressed each outcome.The Committee also considered evidence for causality anddose response in assigning the strength-of-evidencerating.

Reprinted from USDHHS (2008, p. 9).

CHAPTER WRAP-UP

WHAT YOU NEED TO KNOW

Definitions for terms like sedentary behavior, sedentaryactivity, physical activity, exercise, physical fitness, and thephysical activity and exercise continuum are all important tounderstand and to use for effective communication in the fieldof physical activity and public health.The integration of the concepts of kinesiology related topublic health is based primarily on the Physical ActivityGuidelines for Americans (USDHHS 2008, 2018) and thePhysical Activity Guidelines Advisory Committee Report(USDHHS, PAGAC 2008, 2018).The study of kinesiology includes the major exercise sciencesof exercise physiology, the movement sciences, and sportand exercise psychology.An understanding and integration of multiple kinesiologysubdisciplines will help practitioners be successful atdeveloping physical activity and exercise plans to promoteand achieve public health goals.Numerous general and specific health, fitness, andperformance benefits of participating in physical activity andexercise have been reported in the scientific literature.The Physical Activity Guidelines Advisory Committee Report(USDHHS, PAGAC 2008, 2018) includes real-life casestudies of children, adolescents, adults, and older adults whohave become and remained physically active. By learninghow to integrate the physical training concepts presented inthe chapter, you can optimize the success of your physicalactivity and exercise program.An understanding and application of training theory can helppractitioners understand traditional training models designedfor maximizing performance versus new strategies fordeveloping physical activity and exercise plans for promoting

positive health outcomes for not only individuals, butpopulations as well.The volume of physical activity and exercise significantlyaffects dose-response health benefits.It is important to understand information from the exercisesciences (data-based research literature outcomes) andapply it (the clinical practice of using training principles basedon knowledge and experiences) effectively to improve health,fitness, and performance.The intensity of physical activity and exercise when durationis held constant is the most important FITT variable relative tocaloric expenditure (volume) per minute, per hour, per day, orper week.Intensities are often classified in absolute terms (i.e., energyor work required to do an activity without accounting for theperson’s physiological capacity) or relative terms (i.e., takinginto account the person’s exercise capacity, such as apercentage of aerobic capacity).Light physical activity is defined as activity requiring 1.6 toless than 3 METs, such as walking at a slow pace (<2 mph[3.2 km/h]) or cooking activities. Moderate-intensity physicalactivity or exercise is categorized as working between 3 and6 METs, whereas vigorous-intensity physical activity isdefined as working at greater than 6 METs.The amount of physical activity and exercise performed canbe determined by using the absolute intensity or relativeintensity, the time or duration, and the frequency.The art of applying physical activity and exercise trainingprinciples can help practitioners minimize barriers to meetingpublic health recommendations for participation in regularphysical activity and exercise.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYAinsworth BE, Haskell WL, Whitt MC, Irwin ML, Swartz AM, Strath

SJ, O’Brien WL, Bassett DR, Jr., Schmitz KH, EmplaincourtPO, et al. 2000. Compendium of physical activities: An updateof activity codes and MET intensities. Medicine & Science inSports & Exercise 32 (9 Suppl): S498-S504.

American College of Sports Medicine. 2018. ACSM’s Guidelinesfor Exercise Testing and Prescription, 10th ed. Philadelphia:Lippincott Williams & Wilkins.

Blair SN, Kohl HW III, Paffenbarger RS Jr., Clark DG, Cooper KH,Gibbons LW. 1989. Physical fitness and all-cause mortality. Aprospective study of healthy men and women. Journal of theAmerican Medical Association 262 (17): 2395-2401.

Caspersen CJ, Powell KE, Christenson GM. 1985. Physicalactivity, exercise, and physical fitness: Definitions anddistinctions for health-related research. Public Health Reports100: 126-131.

Haskell WL, et al. 2007. Physical activity and public health:Updated recommendation for adults from the American Collegeof Sports Medicine and the American Heart Association.Medicine & Science in Sports & Exercise 39: 1423-1434.

Kenney WL, Wilmore JH, Costill DL. 2019. Physiology of Sportand Exercise, 7th ed. Champaign, IL: Human Kinetics.

McGuire DK, Levine BD, Williamson W, Snell PG, Blomqvist G,Saltin B, Mitchell J. 2001. A 30-year follow-up of the Dallas Bed

Rest and Training Study: I, effect of age on the cardiovascularresponses to exercise. Circulation 104: 1350-1357.

Murray T. D., Eldridge J. A., and Kohl, H. W. III. 2019.Foundations of Kinesiology: A Modern Integrated Approach.Boston, MA: Cengage Learning.

U.S. Department of Health and Human Services. 2008. PhysicalActivity Guidelines for Americans. Washington, DC: U.S.Department of Health and Human Services.www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services. 2018. PhysicalActivity Guidelines for Americans, 2nd ed. Washington, DC:U.S. Department of Health and Human Services.www.health.gov/paguidelines/second-edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2008. Physical ActivityGuidelines Advisory Committee Report, 2008. Washington, DC:U.S. Department of Health and Human Services.https://health.gov/paguidelines/2008/report/pdf/CommitteeReport.pdf.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2018. 2018 Physical ActivityGuidelines Advisory Committee Scientific Report. Washington,DC: U.S. Department of Health and Human Services.https://health.gov/paguidelines/second-edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.1.4, 1.4.2, 2.22, 2.3.3, 2.5.2, 3.1.3, 5.1.1, 6.1.3, 6.1.4,6.2.1, 6.2.2, 6.2.3, 6.2.4, 6.3.3, 6.3.5, 6.4.1, 6.4.2,6.5.4, 6.5.5

CHAPTER 3Integrating Public Health andPhysical Activity

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The history of physical activity and public health»  How science is translated into practice in physical activity

and public health»  How the application of scientific findings differentiates

physical activity and public health from other areas suchas medicine and exercise physiology

»  Knowledge, skills, and aptitudes for careers in physicalactivity and public health

OPENING QUESTIONS»  What is the intersection between kinesiology and public

health?

»  Why is defining this intersection important?»  Is there a career for you in physical activity and public

health?

Physical activity and public health—what do you think of when youread that phrase? Elite Olympic athletes who look to be in idealhealth? Masters-level swimmers who swim a mile each day becausethey enjoy it? Women who work at a factory and spend their lunchhour each day walking 2 miles (3.2 km) together? Constructionworkers who lift, bend, stoop, and carry loads all day? Kids in aphysical education class jumping rope? If you answered yes to all ofthese questions, you are right. Physical activity and public health is afield of study that looks at the health effects and risks of physicalactivity and ways to help people become active and maintain ahealthy level of activity throughout their lives.

Public health is the science and practice of protecting, promoting,and improving the health of populations and communities. Anoverview of public health concepts was presented in chapter 1.Although individual people are important to health careprofessionals, public health is primarily interested in the health ofcommunities or groups of people. When we think of public health,notable achievements such as vaccinations against disease,quarantine rules for controlling disease outbreaks, reductions indeaths resulting from motor vehicle accidents, fluoridation of publicwater supplies to improve dental health, and food safety andrestaurant inspections to reduce food-borne illnesses come to mind.

HISTORY OF PHYSICAL ACTIVITY AND PUBLIC HEALTHAlthough there is evidence that people understood that exercise wasimportant for health all the way back in ancient Greece, the formalstudy of the health effects of physical activity is much newer. Evennewer is what we now know about how to help people change theirbehaviors to take advantage of all the health benefits of a physicallyactive way of life.

An understanding of the evolution of the field of physical activityand public health can come from learning how the two fields ofexercise science and public health science evolved independently inthe 20th century. Exercise science was a developing field in the early1900s, and much of what we now know about exercise physiology,biomechanics, and sport performance can be traced to early work inexercise science. Fundamental understandings of how oxygen isdelivered to working muscles through the cardiovascular system,how carbon dioxide is produced and expelled during exercise, andhow glucose (sugar) is metabolized as the body moves resulted inprominent steps forward in the early part of the last century.

The 20th century also witnessed the expansion of personalphysical education from having a medical focus in the 1800s toproviding sport and games to the masses. Developing fitness formilitary service was also a prominent role for physical education. Theconcept of play as a means to promote health also grew during the20th century.

In the 20th century, life expectancy in the United States increasedby 30 years. Even though fundamental practices of personal andcommunity hygiene and quarantine, and the development of vitalstatistics systems, occurred much earlier, these were modified andupdated in the 20th century. Penicillin, the first antibiotic medicineused to control bacterial infections, was discovered in 1928 byScottish scientist Alexander Fleming. Vaccine development andmass vaccination efforts helped to stem and nearly eliminate seriousinfectious diseases such as polio and smallpox. Major advances infood safety, including handling and storage, were made in the 20th

century, making the food supply safer and reducing the risk ofpathogens being carried in food to humans and animals.

Epidemiology, the basic science of public health, is concernedwith the study of the causes and consequences of disease anddisability in human populations. Initially developed to help peopleunderstand how to identify and prevent infectious diseases such ascholera and tuberculosis prior to 1900, epidemiology has evolved toaddress contemporary health burdens as well, such as heartdiseases, cancers, motor vehicle accidents, and air pollution. Majoradvances in epidemiology also occurred in the 20th century with theemergence of new study designs and observational techniques toassess health outcomes, particularly those related to chronicdiseases in populations. Further, our ability to collect, process, andanalyze data improved with the advent of computing.

The conditions were ripe in the 20th century for the two fields ofexercise science and public health to come together. In fact, such amerger began with the publication of a study conducted in London in1953. A young epidemiologist named Jeremy N. Morris wasinterested in heart disease and its causes and consequences. Dr.Morris chose to study workers employed by the London transportsystem. It was a large group of (mostly) men who worked all daymoving people around the city of London. Dr. Morris was particularlyinterested in the amount of physical activity the men got in thecourse of their jobs and how that related to their risk of having aheart attack.

Figure 3.1   The Routemaster bus, a laboratory of early studies of physicalactivity and health.

A popular form of public transportation in London in the late 1940sand 1950s was the legendary Routemaster (double-decker) bus (seefigure 3.1). Hundreds of these buses operated throughout the city.Although similar buses operate in London today, in the 1950s therewere no computers, magnetic card readers, or other conveniences.Dr. Morris was able to separate the men he was studying into twogroups: the bus drivers who were inactive all day long because theywere sitting and driving the buses, and the conductors who werewalking up and down the stairs of the buses taking tickets from ridersall day (Morris et al. 1953; see figure 3.2). Morris found that thephysically active conductors had significantly lower rates of coronaryheart disease then the less active drivers.

Although these findings may seem fairly straightforward now, atthe time they were quite revolutionary. A shift in the paradigm hadbegun as physical activity for health began to be placed alongsideexercise for performance.

The exercise/heart hypothesis, now more of an accepted fact thana hypothesis, essentially was that people who exercised more

frequently had healthier, better functioning circulatory systems thansimilar people who did not exercise. This physiological benefitresulted in a lower risk of death from heart disease among thosewho were more active. Dr. Morris went on to publish further studiesof occupational physical activity (i.e., physical activity that resultsfrom the job one performs) and he is widely viewed today as thegrandfather of the field of physical activity and public health.

Figure 3.2   Incidence of coronary heart disease in London bus drivers andconductors aged 35 to 64. London Transport Executive 1949-1950.Data from Morris et al. (1953).

Following Dr. Morris, and equally, if not more, effective, was Dr.Ralph S. Paffenbarger Jr. (see figure 3.3). Dr. Paffenbarger wastrained in medicine and studied infectious diseases early in hiscareer. He was extremely influenced by Dr. Morris’ work on theLondon transport workers and set out to improve our understandingof the exercise/heart hypothesis from a public health point of view.As a result of his many influential studies of college alumni and

longshoremen, Dr. Paffenbarger was able to more precisely identifythe amounts and types of physical activity that were associated withimproved health. Thus was born the field of physical activity andpublic health.

Figure 3.3   Dr. Ralph Paffenbarger and Dr. Jeremy Morris, trailblazers inphysical activity and public health.

Into the 1970s and 1980s, observational studies of physicalactivity and health outcomes continued to emerge, as did studies ofexercise dose, performance, and the physiological effects of the two.Researchers began to quantify the substantial health benefits ofphysical activity (and the risks of inactivity); some of these manybenefits are shown in chapter 2. Moreover, during this time itbecame clear that many people throughout the world were notphysically active at levels that could reduce their risk of disease,disability, or both. Populations, not just individuals, were not ashealthy as they could be because of physical inactivity. Suddenly, anexercise and performance problem became a physical activity andpublic health problem (see figure 3.4).

With the scientific cooperation of exercise science andepidemiology taking hold, additional disciplines began to focus onphysical activity and health. Specifically, in the 1990s, behavioralsciences and environmental health sciences were added to thepicture. Behavioral sciences began to explore the determinants ofphysical activity and inactivity and to investigate how inactive peoplecould adopt and maintain healthier behaviors. More recently,environmental health sciences have begun to explore the role thatplace and the built environment play in encouraging or discouragingphysical activity behaviors. Taken together, a new subdiscipline,physical activity and public health, has emerged (see figure 3.5).

Figure 3.4   The merger of kinesiology and epidemiology to create physicalactivity and public health.

Figure 3.5   Physical activity and public health—the emergence of asubdiscipline.

ROLE OF PHYSICAL ACTIVITY IN CHRONIC DISEASEDEVELOPMENTMuch of the interest in physical activity and public health arises fromthe role physical activity plays in the prevention and treatment ofchronic diseases. Chronic diseases are conditions and illnesses thatoccur or develop over a relatively long period of time (months toyears), are prolonged, and may be preventable, but are rarelycompletely cured. Examples of chronic diseases are diabetesmellitus (types 1 and 2), cancer, heart disease, pulmonary disease,and osteoporosis.

Sometimes it is helpful to differentiate chronic diseases(sometimes called noncommunicable diseases) from infectiousdiseases. Infectious diseases are illnesses or conditions that are

caused by pathogens such as viruses, bacteria, and fungi. Mostinfectious diseases can be treated, cured, or controlled withmedicines, vaccines, or other measures such as quarantine.Infectious diseases include influenza, tuberculosis, measles, andmalaria.

Many countries have improved their public health infrastructuresto control the causes of infectious diseases, so chronic diseaseshave become an increasingly significant part of the health burden. Infact, chronic diseases such as cardiovascular diseases (i.e.,diseases of the heart and blood vessels), diabetes mellitus, andsome cancers present the most urgent threat to public health indeveloped countries. At the beginning of the 20th century, the threeleading causes of death in the United States were infectious in theirorigins. That has given way to the current situation where the threeleading causes of death are all chronic diseases, each with a highdegree of association with physical activity. The 10 leading causes ofdeath in 1900 and 2015 are listed in table 3.1.

The most important and powerful health benefits of physicalactivity are the prevention and treatment of chronic diseases.Through a variety of physiological processes, physically activepeople are much healthier and much less likely to develop and diefrom chronic diseases than those who are not physically active.Moreover, physical activity and exercise reduce the risk of dyingprematurely (all-cause mortality). You will learn more about thesehealth benefits throughout part II.

Table 3.1   Ten Leading Causes of Death in the United States:1900 and 2015

Rank 1900 2015

1 Pneumonia (all forms) and influenza Heart disease

2 Tuberculosis (all forms) Cancer

3 Diarrhea, enteritis, and ulcerationof the intestines

Chronic lower respiratorydiseases

4 Diseases of the heart Accidents (unintentionalinjuries)

5 Intracranial lesions of vascularorigin

Stroke (cerebrovasculardisease)

6 Nephritis (all forms) Alzheimer’s disease

7 All accidents Diabetes mellitus

8 Cancer and other malignant tumors Influenza and pneumonia

9 Senility Nephritis, nephrotic syndrome,and nephrosis

10 Diphtheria Intentional self-harm (suicide)

Adapted from Center for Disease Control and Prevention. Available: www.cdc.gov/nchs/FASTATS/lcod.htm and www.cdc.gov/nchs/data/dvs/lead1900_98.pdf.

FROM SCIENCE TO PRACTICE AND BACKPublic health is characterized by science and action. Epidemiologyprovides the fundamental science. The action aspect is theimplementation of findings from scientific studies to improve health,which is what differentiates the field of public health from other basicscience and biomedical science disciplines. Public health appliesscience to practice by addressing three critical areas: surveillance,community interventions, and the development of health guidelines.

SURVEILLANCEPublic health surveillance has been defined as the ongoing,systematic collection, analysis, and interpretation of data (e.g.,regarding agent or hazard, risk factor, exposure, or health event)essential to the planning, implementation, and evaluation of publichealth practice (Thacker 1988). Surveillance is a critical public healthfunction because it helps us understand the extent of a health

problem and identify the types of people and populations that maybe at higher risk of that health problem. The number of weekly casesof influenza, the annual death rate due to malaria, the number ofheart attacks among older African American adults, and thepercentage of high school students who take daily physicaleducation classes are all real-life examples of surveillance data thatare routinely collected by public health professionals.

The CDC has developed a variety of surveillance systems tomonitor the health of the U.S. population. More information onsurveillance for physical activity and public health can be found inchapter 4.

COMMUNITY INTERVENTIONSInterventions—preferably at the community level—are anothercornerstone of public health. The science behind interventions isestablished during projects called efficacy trials. Efficacy trials arestudies that are used to establish that a certain intervention or publichealth program can change a certain condition. For example,efficacy trials have been used in small interventions to test theprocess of supplementing a person’s diet with iron to cure iron-deficiency anemia, a dangerous condition in which the body does nothave enough red blood cells to carry oxygen. A study could bedesigned that randomly assigns infants that have low levels of iron intheir blood to two different conditions: In one condition iron would begiven to the mother in the form of a pill (and be delivered to the infantthrough breast-feeding), and in the other condition iron would bedelivered directly to the infant in an infant formula drink. The studywould evaluate which of the two methods works better at increasingstores of iron in the bodies of infants.

Effectiveness studies are the other main type of intervention studyof interest in public health. In effectiveness studies, the mainoutcome of interest relates to how well a treatment works in practice—or more appropriately, in real life instead of in controlled settings. Ifwe consider the preceding iron-deficiency anemia situation, the

appropriate effectiveness question becomes: How well does the ironsupplementation delivery method work in a community or village inwhich malnutrition is rampant? Obviously, many questions arise inthis kind of study. For example, even if we know that the breast-feeding method appeared to work better in the efficacy study, it maynot be particularly effective in a certain area because of cultural orsocial restrictions on breast-feeding. This presents a clear dilemmafor a public health intervention—efficacy data show one route to go,but the real-life (effectiveness) evaluation of the interventionsuggests something different. This situation requires additional studyand observation to refine the methods to ensure the effectiveness ofthe intervention.

Similar challenges become apparent in the world of physicalactivity and public health. From exercise physiology, we know thephysiological effects of a prescribed dose of exercise onphysiological parameters such as cardiorespiratory fitness, bloodpressure, adverse lipid and lipoprotein levels, body weight, andblood glucose response. These results come from carefullycontrolled laboratory efficacy trials in which the dose of exercise ismanaged tightly and measured very closely. Exercise has a knownefficacy for improving many parameters that are related to poorhealth in the human body. The effectiveness of such interventions inreal life becomes much more difficult and challenging to measureand assess when these studies are taken out of the laboratory andinto the community. How do we translate laboratory-based studiesinto community interventions that will help people increase theirphysical activity levels and thus become healthier? This practiceaspect of public health is the main focus of the third part of thistextbook.

DEVELOPMENT OF HEALTH GUIDELINESThe development of health guidelines is a third critical function ofpublic health science. Public health guidelines are official policystatements, usually developed by a government body, agency, or

other reputable organization, that are based on the best availablescience. Public health guidelines provide clear recommendationsabout a course of action to deal with a pressing public health issue.Recommendations for childhood immunization schedules (when andwhich vaccines and their timing), diabetes treatment (the frequencyand method of glucose self-monitoring), nutrient intake (micronutrientdaily recommended intakes for health), and annual influenzavaccinations (type and timing) are all examples of public healthguidelines that, based on the best available science, give healthprofessionals and the public clear guidance about the mostappropriate courses of action for preventing and treating certainhealth problems.

In 2008, the U.S. Department of Health and Human Servicespublished the first Physical Activity Guidelines for Americans(USDHHS 2008; see the highlight box 2018 Physical ActivityGuidelines for Americans). These guidelines, updated in 2018, arebased on comprehensive scientific summaries to detail the bestscience-based recommendation for the weekly amount of physicalactivity necessary to prevent disease and promote positive healthoutcomes (USDHHS 2018). The physical activity guidelines weredeveloped for children and adolescents, adults, and older adults.These guidelines should be used as targets for physical activityparticipation.

Several other countries, as well as the World Health Organization,have published guidelines similar to the Physical Activity Guidelinesfor Americans. Japan, Canada, Australia, and England have alltaken leadership roles in establishing physical activity as a publichealth priority by setting physical activity guidelines andrecommendations.

2018 PHYSICAL ACTIVITY GUIDELINES FORAMERICANSChildren (Aged 3 to 5 years)

Preschool-aged children should be active throughout

the day to enhance growth and development. Children

this age should be encouraged into active play for at

least 3 hours per day.

Children and Adolescents (Aged 6 to 17 years)

Children and adolescents should do 1 hour (60 min) or

more of physical activity every day.

Most of the 1 hour or more per day should be either

moderate- or vigorous-intensity aerobic physical

activity.

As part of their daily physical activity, children

and adolescents should do vigorous-intensity activity

at least 3 days per week. They also should do muscle-

strengthening and bone-strengthening activity at

least 3 days per week.

Adults (Aged 18 to 64)

Adults should do 2 hours and 30 minutes per week of

moderate-intensity, or 1 hour and 15 minutes (75

minutes) per week of vigorous-intensity aerobic

physical activity, or an equivalent combination of

moderate- and vigorous-intensity aerobic physical

activity. Aerobic activity should be performed in

episodes of at least 10 minutes, preferably spread

throughout the week.

Additional health benefits are provided by increasing

to 5 hours (300 minutes) per week of moderate-

intensity aerobic physical activity, or 2 hours and

30 minutes per week of vigorous-intensity physical

activity, or an equivalent combination of both.

Adults should also do muscle-strengthening activities

that involve all major muscle groups performed on two

or more days per week.

Older Adults (Aged 65 and Older)

Older adults should follow the adult guidelines. If

this is not possible due to limiting chronic

conditions, older adults should be as physically

active as their abilities allow.

It is important for older adults to avoid inactivity.

Older adults should do exercises that maintain or

improve balance if they are at risk of falling.For all individuals, some activity is better than none

and everyone should move more and sit less. Physicalactivity is safe for almost everyone, and the healthbenefits of physical activity far outweigh the risks.People without diagnosed chronic conditions (e.g., who donot have conditions such as diabetes, heart disease, orosteoarthritis) and who do not have symptoms (e.g., chestpain or pressure, dizziness, or joint pain) do not need toconsult with a health care provider about physicalactivity.

PROMOTING PHYSICAL ACTIVITY FOR HEALTHAs the field of physical activity and public health has emerged, it hasbecome clear that many factors at many levels influence physicalactivity behaviors. Many investigators have used the socialecological model as a guiding framework to explain these multiplelevels. They are illustrated in figure 3.6 and form the basis for thethird section of this textbook.

At the center of the target in the social ecological model forphysical activity behaviors are individual factors. These are thefactors that are innate to each person and that differ among people.A person’s genetic makeup, early life experiences (e.g., youth sportparticipation), self-efficacy, and other factors, such as sex, disability,growth and development, and socioeconomic status, may all beimportant determinants of health behaviors such as physical activity.

Figure 3.6   Multiple levels of influence on physical activity behaviors: Thesocial ecological model.

Moving out from the center, social influences on physical activityare important. Research has now shown that individual factors arenot enough to explain physical activity behavior. Determinants at thesocial influences level aren’t characteristics of the person per se, butare, rather, characteristics of how the person interacts with society orculture. Influences at this level can include peers, medical careorganizations (doctors), family members, and organizations (schools,places of worship, worksites).

The third level in the social ecological model representsenvironmental influences. These influences may enhance or restrictphysical activity behaviors, and are external to the person butcommon across societies and cultures. Research on the effects ofphysical environment on physical activity participation has explodedas the field of physical activity and public health has emerged. Theability to influence the physical activity of vast numbers of people(instead of one person at a time) by making a single change makesenvironmental influences on physical activity a particularly interestingarea of research. The availability of places to be active, such astrails, sidewalks, fitness facilities, bicycle lanes, community and

neighborhood design elements are examples of how the builtenvironment can influence physical activity.

Finally, the outer level represents policy influences on physicalactivity. Influences in this sphere include written or unwritten rules,codes, and norms that influence environmental or socialdeterminants of physical activity. As with the physical environment,determinants at this level are particularly attractive because of theirpotential to influence many people. Examples of policy influences onphysical activity include policies allowing increased access to placesto be physically active (making it easier to be physically active),educational policies (e.g., mandating high-quality daily physicaleducation for schoolchildren), and transportation-related policies(e.g., making it easier to walk or bicycle for transportation).

By combining knowledge, skills, and abilities related to the basicexercise sciences and public health, you can better explain anddiscuss professionally the health benefits and risks of exercise andphysical activity to your peers, colleagues, and the communities youserve (see part II, chapters 5 through 10). An understanding of thespecific challenges that affect physical activity and exercise inprofessional exercise science jobs can clarify how the exercisesciences affect public health, and vice versa. The highlight boxCareers Combining Exercise Science and Public Health lists careersin exercise physiology, biomechanics, and sport and exercisepsychology that are commonly seen in the professional areas ofhealth and fitness, preventive medicine, athletic performance, andrehabilitation.

PRACTITIONERS OF PHYSICAL ACTIVITY IN PUBLIC HEALTHPhysical activity and public health is an emerging discipline withmany opportunities. People with training in this area, particularly atthe master’s level, are employed in state and local healthdepartments working on public health programming for physicalactivity promotion. Many universities have research opportunities forpeople interested in studying physical activity and public health.

Finally, private foundations and nongovernmental organizations areinterested in people with training and interests in physical activityand public health.

LEADER PROFILEI-Min Lee, MBBS, MPH, ScD

Why and how did you get into the field of PhysicalActivity and Public Health?I was trained as a physician and an epidemiologist. Earlyin my career, I primarily focused on epidemiologicinvestigations of risk factors for cancer, in particular,physical inactivity and adiposity. My research interestwas more narrowly targeted— concentrating on identifyingpreventive/risk factors— rather than a more broadapplication to public health.

With the publication of the 1995 physical activityrecommendation from the Centers for Disease Control andPrevention and the American College of Sports Medicine,and the 1996 surgeon general’s report on physical activityand health, I realized that while risk factoridentification is crucial, the knowledge just “sits”unless it is translated into a method in which it can beapplied. For example, in my specific area of interest, thepractical questions—what types of physical activity, whatintensity, how much, and how often—need clarification tobe useful for public health translation.

Did any one person have a major influence on your career?How?Without question, the late Professor Ralph S.Paffenbarger, Jr.—one of the pioneers in the field ofphysical activity epidemiology—was single-handedlyresponsible for guiding me into this field of research. Iwas working as a postdoctoral fellow on a research studyof mycosis fungoides (a type of cancer), when I met Paff,as everyone called him. He invited me to work on his long-standing cohort study of physical activity and healthamong college alumni. I really wasn’t interested at all,since I did not have any background in this area, plus Iwas physically inactive! But Paff was very persistent, andI eventually agreed. With Paff as my advisor, I then wenton to complete a doctoral degree in epidemiology, usinghis data for my thesis. I do realize how lucky I was thatPaff dropped into my life; he was a truly knowledgeableand generous mentor. He pushed me into writing andspeaking engagements that advanced my career, and was verygenerous in sharing credit with me. I have no doubt thatPaff is responsible for where I am today.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?My current interest is investigating the dose of physicalactivity (and sedentary behavior) needed for health inorder to inform public health recommendations. While we dohave guidelines (the most current U.S. recommendations

being the federal Physical Activity Guidelines forAmericans, 2nd ed.), the scientific basis for existingguidelines is largely derived from studies using self-reports of physical activity. It has become increasinglyfeasible to use devices in large-scale research studiesfor measuring physical activity and sedentary behavior.The ability to use devices is an exciting development inthe field of physical activity research, yielding largevolumes of data to address detailed questions related totypes, intensity, duration, frequency, and patterns ofphysical activity that are healthful, and informing publichealth and clinical guidelines.

Why do you do what you do?

In addition to finding the methodological approaches forusing device-collected data challenging and veryinteresting, physical activity has the potential tobenefit the health of large numbers of people throughoutthe world. Insufficient physical activity (i.e., notmeeting guideline levels) has been estimated to cause morethan 5 million deaths worldwide each year (Lee et al.2012)—a number equivalent to that caused by smoking. Arecent publication (Guthold et al. 2018) emphasizes thiscontinuing public health problem, noting a high prevalenceof insufficient physical activity worldwide at 27.5%; thisfigure was highest in affluent countries such as theUnited States.

What are two key issues that must be addressed by 2030?There are many public health issues that we face today.One urgent issue that comes to mind is addressing climatechange: Global warming could cause parts of the world,particularly low- and middle-income countries, to becometoo hot for people to be physically active comfortably,potentially leading to even less physical activity. Asecond issue is a need for government commitment tosupport population-based, multi-sectoral and multi-disciplinary policies to increase the activity levels—andhence, health—of their populations.

CAREERS COMBINING EXERCISE SCIENCE ANDPUBLIC HEALTH

Physical education teacher

Physical activity specialist

Firefighter

Police or military

Personal trainer

Physician

Nurse

Researcher

Movement specialist

Wellness coach

Clinical exercise physiologist

Translational exercise physiologist

Coach

Sporting goods representative

Biomechanist

Sport physiologist

Health or fitness facility owner

Physical therapist

Cardiac rehabilitation specialist

Occupational therapist

Diabetes or obesity prevention specialist

Athletic trainer

Consultant

Translational biomechanist

In 2006, a new professional organization was created in theUnited States. The National Society of Physical Activity Practitionersin Public Health (NSPAPPH) is now called the National PhysicalActivity Society (NPAS). The NPAS is a dedicated group ofprofessionals interested in advancing the capacity of professionals inphysical activity and public health in the United States. The grouphas taken a major leadership role in developing a definition of what itmeans to be a professional in the field of physical activity and publichealth and what core competencies are necessary for leadership incommunity-level interventions to promote and evaluate theeffectiveness of those interventions. Many of the core competenciesput forth by NPAS are addressed in this textbook and are found atthe end of each chapter as a cross-reference.

NPAS has developed resources, trainings, and a certification(Physical Activity and Public Health Specialist) to createprofessionals in physical activity and public health. The certificationis a voluntary credential that is a U.S. national standard forprofessionals working in this area. Important knowledge, skills, andabilities in partnership development, planning and evaluation,exercise science, development of effective interventions, andevaluation of scientific data are part of NPAS’ training andcertification procedure. Knowledge and skills in each of these areasare critical for advancing physical activity and public health anddeveloping a successful career in the field.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

Physical activity and public health is an emerging disciplinethat combines science and practice from the exercise sciencedisciplines and from public health and epidemiology.Physical activity, exercise, and physical fitness are threeconcepts that are relevant to physical activity and publichealth.Surveillance, community interventions, and the developmentof health guidelines are three key pillars of public health.The Physical Activity Guidelines for Americans are science-based summaries of the amounts and types of physicalactivity that produce health benefits for all ages.All humans should move more and sit less.A variety of careers are available to people with an interestand training in physical activity and public health.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYGuthold R, Stevens GA, Riley LM, Bull FC. 2018. Worldwide

trends in insufficient physical activity from 2001 to 2016: Apooled analysis of 358 population-based surveys with 1·9million participants. Lancet Global Health 6: 1077-1086.

Lee IM, Shiroma EJ, Lobelo F, Puska P, Blair SN, Katzmarzyk PT,Lancet Physical Activity Series Working Group. 2012. Effect ofphysical inactivity on major non-communicable diseasesworldwide: An analysis of burden of disease and lifeexpectancy. Lancet 380: 219-229.

Morris JN, Heady JA, Raffle PAB, Roberts CG, Parks JW. 1953.Coronary heart disease and physical activity of work. Lancet262: 1053-1108.

Thacker SB, Berkelman RL. 1988. Public health surveillance inthe United States. Epidemiology Review 10: 164-190.

U.S. Department of Health and Human Services. 2008. PhysicalActivity Guidelines for Americans. Washington, DC: U.S.Department of Health and Human Services.www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services. 2018. PhysicalActivity Guidelines for Americans, 2nd ed. Washington DC:U.S. Department of Health and Human Services.www.health.gov/paguidelines/second-edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.4.1, 2.1.1, 2.1.3, 2.2.1, 2.2.2, 2.2.3, 4.5.1, 4.5.2,4.5.3, 4.5.4, 5.1.1, 5.1.2, 5.4, 5.4.1

CHAPTER 4Measuring Physical Activity

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  Techniques to measure physical activity among individualsand populations

»  The strengths and weaknesses of these techniques»  Fundamentals of physical activity surveillance»  Sources of public health information on physical activity

OPENING QUESTIONS

»  What are the best ways to measure physical activity inindividuals and in populations?

»  Can people accurately remember their physical activitypatterns for weeks or months?

»  How useful are new technologies to help us measure physicalactivity?

As you learned in chapter 2, physical activity is any skeletalmovement that results in energy expenditure; therefore, physicalactivity per se is a behavior (i.e., the act of moving), and energyexpenditure is the direct result that physical activity has on ourbodies. The most accurate techniques to measure physical activityare those that involve quantifying the amount of energy expenditurethat results from being physically active. Energy expenditure can bequantified in units called kilocalories, which are often referred to asjust calories. Anytime you move your body—from getting out of bedin the morning, to walking to the bus stop, to playing basketball, towalking down the hallway—you are being physically active andtherefore burning calories.

You also previously learned about the different intensities ofphysical activity. Physical activities of moderate or vigorous intensityare most beneficial to health. When considering ways to measurephysical activity, keep in mind that people can be moderately orvigorously active within different domains—that is, they can engagein physical activity for different reasons such as during one’s freetime (also known as discretionary, recreational, or leisure-timedomain), by walking or biking to get to and from places(transportation domain), as part of one’s job (occupational domain),or by doing activities like heavy yard work or cleaning at home(household domain). Although the term exercise is often usedinterchangeably with physical activity, exercise is a subset ofphysical activity, and falls under the domain of leisure-time physicalactivity. Exercise is planned, structured, repetitive, and designed to

increase or maintain physical fitness. Taking a 30-minute walk,jogging, playing basketball or tennis, and hiking and mountainclimbing are all examples of exercise, since they are planned,structured, repetitive, and, most critically, they all help increase ormaintain physical fitness.

As highlighted in chapter 2, physical activity and physical fitnessare unique constructs. Physical activity is a behavior, and physicalfitness is a physiological state. Because exercise is a subset ofphysical activity, it is also a behavior. Although this chapter focuseson the measurement of physical activity, there are also a wide varietyof fitness assessment and measurement strategies and tests. Thesetests have been developed following years of research about thehuman body’s adaptation to regular physical activity.

Understanding measurement and assessment techniques forphysical activity and physical fitness, assessing the strengths andweaknesses of these techniques, and knowing how and with whomto use them is critical for understanding and conducting studies ofphysical activity and health. This understanding is also importantwhen developing, implementing, and evaluating programs forincreasing physical activity in individuals and populations. Thischapter gives an overview of current techniques in this area.

EVIDENCE-BASED RECOMMENDED LEVELS OF PHYSICALACTIVITY FOR HEALTHWe know that physical activity is good. Since the early studies in the1950s and 1960s, we have learned more about the importance ofthe intensity, frequency, and duration—as well as the total volume—of physical activity as they relate to health. This new knowledge hasits roots in exercise science and exercise training studies. Today, weknow that being routinely active has substantial benefits forcardiovascular and metabolic health, cancer prevention, mentalhealth, sleep quality, physical function, and quality of life.

The best science-based guidelines state that adults shouldaccumulate at least 150 minutes per week of moderate-intensity

physical activity, or at least 75 minutes per week of vigorous-intensityphysical activity, or some equivalent combination of intensities (U.S.Department of Health and Human Services [USDHHS] 2018). Adultsshould also engage in moderate- or high-intensity muscle-strengthening activities that involve all major muscle groups on twoor more days a week. Additionally, children need at least 60 minutesof moderate-intensity physical activity each day. Finally, we nowknow that for people not currently meeting the minimum guidelinesfor physical activity for their age group, substituting moderate- oreven light-intensity physical activity for sedentary time can result inimportant health benefits.

With these guidelines in mind, we consider these questions: Whatare the best ways to measure physical activity? How well do thesetechniques measure what we want them to measure? Are theyrepeatable? What is needed to measure physical activity mostaccurately among individuals (as opposed to populations)? Whatmethods should we use in controlled laboratory settings, and whichare best for free-living individuals or populations?

LABORATORY MEASURES OF ENERGY EXPENDITURELaboratory-based techniques that measure physical activity arebased largely on the desire to assess caloric expenditure, or theamount of energy a person burns while being physically active,breathing, circulating blood, and digesting food. Total energyexpenditure (TEE) is the sum of all of these components. Physicalactivity energy expenditure (PAEE) is the energy expenditure thatis specifically the result of physical activity. The thermic effect offood (TEF) is the amount of energy that is used to digest andmetabolize energy that is ingested (food and drink). Finally, basalmetabolic energy expenditure (BMEE) is the energy expended tomaintain breathing and circulation at rest.

Roughly 60 to 70% of a person’s TEE is composed of BMEE.Approximately 10% of TEE is used to digest food. The remainingexpenditure (20 to 30%) is for physical activity. Obviously, people

who are more active and those who exercise use a higher proportionof their TEE for physical activity than people who are largelysedentary throughout the day. Because PAEE is the only componentof TEE that is very changeable, we need to know how to measurethat 20 to 30% very well. See figure 4.1 for more details about thedeterminants of TEE.

Figure 4.1   Total energy expenditure = basal metabolic energy expenditure +physical activity energy expenditure + thermic effect of food.

INDIRECT CALORIMETRY

In the laboratory, the process of measuring the components ofenergy expenditure is fairly straightforward. Indirect calorimetry is thetechnique that is used most often. With indirect calorimetry, theamount of oxygen used and carbon dioxide expelled is used toestimate energy expenditure. This can be done using a facemaskand gas analysis system. Another method is when a person lives ina controlled room or setting for a period of time. Energy expenditureis assessed from air samples that are collected while the person is inthe room. Calibrated gas collection devices are used to measure andanalyze oxygen and carbon dioxide changes in the room.

Because carbon dioxide is a by-product of energy metabolism, itis a very good indicator of total energy expenditure in this controlledsetting. Someone who burns more energy in this setting (e.g.,through exercise) is easily differentiated from someone who issedentary and not burning any additional calories. By having thesubject keep a diary, or by having study personnel observe thesubject, investigators can quantify the amount (frequency, intensity,and duration) and type of physical activity performed during anindirect calorimetry study. Thus, PAEE can be measured as well.This, coupled with careful measurements of the food eaten andwaste produced, can give a very accurate measure of TEE.

Although indirect calorimetry is very accurate, it has limitations.First, it is relatively expensive. A special room must be built, gasanalyzers must be installed, and study personnel must be hired tomaintain the facility, among other costs. Second, only one person ina room (two if there are two rooms) can be measured at a time. Thismakes larger studies more tedious to conduct and quite lengthy tocarry out. Another limitation is that the equipment needed to dothese analyses can break down and usually must be calibratedfrequently so that the investigator has confidence in themeasurements. A final limitation is that this type of protocol does notcapture TEE or its components in real life. That is, the artificiallaboratory settings do not allow people to live as they wouldnormally. This is of obvious importance in the public health world.

DOUBLY LABELED WATERA second laboratory technique that has been shown to be veryaccurate in measuring TEE is the doubly labeled water technique.This technique uses the principles of indirect calorimetry bymeasuring the turnover rates of oxygen and hydrogen: The higherthe TEE, the higher the turnover rates (because of higher metabolicactivity).

Doubly labeled water study participants are given a prespecifieddose of stable radioisotope-labeled water. After taking some baselinemeasurements, investigators measure the excretion of the isotopesover the course of one to three weeks (depending on the studyquestion and protocol) in collected urine samples. The difference inelimination rates between the labeled oxygen and hydrogen is usedto estimate carbon dioxide production, which, as in indirectcalorimetry, can be used to estimate TEE.

Doubly labeled water is a very safe procedure that allows peopleto live their lives normally (i.e., they are not confined to a calorimetryroom), and has been shown to be very precise. Participants mustcollect and store urine samples frequently, which can be a burden,and the radiolabeled hydrogen and oxygen are fairly expensive($280 to $800 in USD in 2018). Moreover, substantial equipment (amass spectrometer) and assay tools are needed for analyzing thesamples. Another important limitation is that the assay allows onlythe estimation of TEE. Estimation of PAEE is unattainable using thedoubly labeled water method unless the investigator also has ameasure of BMEE from indirect calorimetry (remember that TEE =BMEE + PAEE + TEF). This can be a significant limitation ifassessment of PAEE is the desired outcome. Further, the methodtells us nothing (alone) about how or why the physical activity wasperformed (e.g., walking for recreation or walking for transportation).This type of information (i.e., domains of physical activity) is usuallyhelpful if understanding why people are active or inactive, orchanging physical activity behaviors is of interest.

ELECTRONIC DEVICES TO MEASURE PHYSICAL ACTIVITYEarly studies in the field have relied on self-report instruments toassess physical activity. We will learn more about self-reportmeasures further along in this chapter. Advances in technology,however, have resulted in the development of devices that canobjectively measure movement (see figure 4.2).

Figure 4.2   Wearable devices that capture movement and acceleration havegreatly increased the ability to measure human physical activity.

ACCELEROMETERSAccelerometers are small piezoelectric devices that measure themagnitude and direction of acceleration. Accelerometers of manyvarieties are used for applications as varied as oil and gas drilling,navigation, and transportation. For human movement and physicalactivity, accelerometers have proven very useful in determining totalphysical activity and in estimating energy expenditure. However,although accelerometers have advanced our ability to measurephysical activity, they provide no information regarding the type ofactivity being performed. For example, a period of brisk walking isindistinguishable from a tennis match to an accelerometer.

Accelerometers measure movement and physical activity bymeasuring acceleration forces in one, two, or three planes (or axes)

as a result of a change in the velocity of the body. Semiconductorstranslate the processing of movement to acceleration. The followingsimple equation shows the mathematical relationship betweenacceleration (a), change in velocity (Δv), and change in time (Δt). Asvelocity increases for a given time, so does acceleration. When theamount of time decreases (at a constant velocity), acceleration alsoincreases.

a = Δv / ΔtUsing this relationship, an accelerometer worn against a person’s

body measures changes in velocity and time. Accelerometers recordthese measures as counts—numerical values given to theacceleration recorded at a given point in time. Counts alone are notvery meaningful, because the scale is an arbitrary one that variesdepending on the make and model of the accelerometer. Modern-day research-grade accelerometers record between 30 and 120 datapoints (counts) per second. The number of counts collected persecond by the accelerometer is referred to as the sampling rate.Because such sampling rates produce a very large amount ofinformation, researchers usually export the data by aggregating themto the 1-second, 10-second, 30-second, or 60-second level. Thisaggregated time segment is known as an epoch. For instance, if anaccelerometer uses a sampling rate of 30 counts per second, andwe use a 60-second epoch to summarize the data, each data point(cell) in our accelerometer dataset would represent the averagevalue of 1,800 counts (30 counts per second × 60 seconds in theepoch). Counts per epoch can then be converted into estimates ofenergy expenditure. Several researchers have conducted laboratory-based studies employing different models and brands of research-grade accelerometers to develop specific energy expenditureformulas. Most accelerometer energy expenditure formulas arebased on counts per minutes; that is, they assume a 60-secondepoch. These formulas are useful because they provide cut pointsfor different intensities of physical activity. These cut points tell us the

minimum number of counts per minute that need to be recorded byan accelerometer to indicate light-, moderate-, or vigorous-intensityphysical activity. Something critical to keep in mind when usingaccelerometers is that physical activity intensity cut points are age-and brand-specific. One must become familiar with all the models,brands, and energy expenditure formulas (cut points) availablebefore collecting and processing accelerometer data in a givenstudy.

Accelerometers are very useful for measuring physical activitybecause they take human recall out of the equation. Participants canattach an accelerometer unit to a waistband and forget it throughoutthe course of the day—they are free to go about their usual activitiesof daily living without having to remember anything. In addition toestimating time spent at specific intensities of physical activity,accelerometers can also determine time spent in continuous periodsof physical activity above a certain time threshold (e.g., 10-minutebouts). Continued technological advances allow for multiday datastorage (sometimes more than 20 days) for long-term behaviormonitoring.

Accelerometers can be relatively expensive (the better onesexceeded $225 USD in 2018) and may not be accurate for all kindsof activities. Most accelerometers are not waterproof; thus, theycannot be used to measure physical activity in the pool, ocean, oranywhere it is wet. Most accelerometers accurately record physicalactivity levels when worn on the waist, making them an inadequateinstrument for measuring bicycling activity. Because downloading,processing, and analyzing accelerometer data is a complex taskrequiring high-level training, accelerometers are best suited forrigorous research studies.

Figure 4.3   GPS monitor.

GEOGRAPHIC POSITIONING SYSTEMS (GPS) MONITORSIn recent years, investigators have started to use wearable GPSmonitors to measure and characterize physical activity spatialpatterns. Research-grade GPS devices collect accurate geographiclocation data every 5 to 60 seconds. These instances, referred to aswaypoints, represent each geolocation where a participant isdetected via satellite systems every x seconds. In addition torecording locational characteristics (latitude and longitude), eachwaypoint contains additional critical information: a date stamp, a timestamp, and a measure of altitude. By using these variables together,we can derive the velocity at which a person is traveling in space(from waypoint A to waypoint B to waypoint C and so on).Investigators employ algorithms to categorize trips as car-based,bicycle-based, or walking based on velocity data. This travel modedetection and the total minutes per day spent in active travel are the

typical physical activity indicators that can be obtained from GPSmonitors. However, a small number of researcher groups around theworld have now begun to simultaneously collect GPS andaccelerometer data. Using complex time-matching algorithms, thecombined use of GPS and accelerometers allows investigators tomap moderate- and vigorous-intensity physical activity in space(e.g., to identify the places within a city where most physical activityoccurs), as well as to detect and assess duration and intensity ofbicycling behaviors (which are difficult to assess with accelerometersalone).

Like accelerometers, GPS monitors remove human recall out ofthe equation, making them a powerful assessment tool. Also likeaccelerometers, GPS devices can be attached to a waistband (seefigure 4.3), are relatively expensive (high-quality models exceeded$200 USD per unit in 2018), and require highly trained individuals fordata download, processing, and analysis. Because of the largeamount of spatial data being collected by GPS monitors, battery lifecontinues to be a significant drawback for these instruments. Mostresearch-grade GPS devices have to be recharged by the participantnightly to ensure sufficient battery life for another full day of datacollection. It is expected that with time these technologies willimprove, allowing for longer battery lives and continuous days orweeks of data collection. One limitation of GPS monitors, when usedalone (as opposed to simultaneously with accelerometers) is thatthey only capture physical activity with spatial displacements(moving from point A to point B in space). GPS monitors alone wouldnot be useful to assess physical activity occurring in a static point inspace (e.g., treadmill running). Ethical concerns related toparticipants’ privacy are also a consideration when dealing with GPSmonitors for physical activity assessment. Some people are hesitantto participate in studies that will collect continuous data on theirwhereabouts. Rigorous protocols that protect participants’ right toprivacy, and that safeguard their geolocational data, must be

followed and further enhanced as these instruments becomeincreasingly popular for physical activity research.

PEDOMETERSPedometers (or step counters) are another kind of electronicmonitoring device that can be used to take the recall bias out ofphysical activity assessment. They are usually most useful formeasuring walking, running or jogging, or any other type of physicalactivity that involves the lower body. Many kinds of pedometers exist,using several types of mechanisms, although they all fundamentallymeasure total steps (see figure 4.4). Some rely on a spring or aspring lever to record the movement, others use a strain gauge, andstill others use a magnetic switch.

Figure 4.4   A pedometer is an inexpensive and easy way to track the numberof steps taken over a period of time. It can also be a useful reminder, andcan help people set goals for steps per day.

A key strength of pedometers is that they are fairly inexpensiveand thus can be used by many people (good pedometers could bepurchased for $15 to $40 USD in 2018). They are fairly simple andstraightforward to use and seem to accurately measure the numberof steps taken. Studies have shown a range of accuracies amongvarious brands, with the less expensive pedometers generally beingless accurate than more expensive ones. Pedometers help peoplebecome more active by reporting the total number of steps they have

taken (e.g., toward a preset goal), thereby reminding them to beactive.

When collecting pedometer-based physical activity data, the leastcommon denominator is steps taken during the observation period.With additional data collection, such as a diary or questionnaire, orwith better pedometer models, one can obtain information on stepstaken per day or steps within different periods of the day, weekdaysversus weekends, and so on. A substantial drawback to usingpedometers for measuring physical activity is that they do not directlymeasure velocity or time and thus cannot estimate acceleration. Thismeans that time spent in different intensities of physical activitycannot be derived simply by having information on total steps takenover a period of time. A pedometer weights each recorded step withthe same value, whether that step was taken while strolling slowly,during a sprint run, or during a soccer game. Clearly, the dose ofphysical activity differs in these various situations, but a pedometerwould not be able to determine that without additional datacollection.

CONSUMER-BASED WEARABLE TRACKING DEVICES AND APPSMost people in high- and middle-income countries, and a substantialproportion of people in low-income countries, now carrysmartphones. In recent years, there has been a rapid surge in theavailability of smartphone applications (apps) for health-monitoringpurposes. This includes apps to monitor one’s physical activitylevels. While many apps simply offer monitoring services, others alsoinclude interactive features such as competition with other appusers, or goal-setting, to help the user achieve a better health status.In addition to smartphone apps, many people also own wearablewristband monitors (e.g., Fitbit) that link to one’s smartphone via Wi-Fi or Bluetooth, and that track physical activity patterns throughoutthe day. These apps and tracking devices rely on technologiessimilar to those previously described, including built-in pedometersand GPS receivers. However, the technology in these consumer-

based products is usually not as advanced as those found inresearch-grade devices, and the algorithms used to deriveacceleration and velocity, and thus energy expenditure, are mostlyunknown because these are proprietary products.

While some research has emerged in an attempt to determine ifthese new technologies are good at accurately measuring physicalactivity in individuals and populations, to date, these consumer-based tracking devices are not considered ideal for measurementpurposes in research. Some of their limitations includeunstandardized wearing positions (some people carry theirsmartphone in their pocket, others put it in a backpack or purse), lowvalidity when compared to research-grade accelerometers, and highpotential for reactivity due to the readily available information aboutthe user’s activity patterns. Reactivity is the tendency to modify one’shabitual behavior after becoming aware of being measured orobserved. The phenomenon of reactivity can be very difficult tocontrol in studies of physical activity behavior, but it becomesparticularly problematic when participants have direct and real-timeaccess to the results of the measures being performed, as is thecase with consumer-based tracking devices and apps.

DIRECT OBSERVATION TECHNIQUESA popular way to measure physical activity behavior is the directobservation of people using certain places of interest. Using trainedobservers, researchers can get a standardized view of physicalactivity participation and intensity for groups of people (e.g., theamount of time children are inactive during a physical educationclass). These observers, who are trained to recognize certaincharacteristics of physical activity such as intensity level, record whatthey see during a period of time. These observations can then beconverted to estimates of group-based energy expenditure based onthe proportion of participating group members, and the distribution ofintensity, frequency, and duration of the physical activity or exerciseobserved. Direct observation techniques are the only available direct

measure of physical activity behavior and are considered anobjective measure of physical activity behaviors when properlyimplemented.

SOFIT AND SOPARCSOFIT (system for observing fitness instruction time) andSOPARC (system for observing play and recreation incommunities) are two excellent examples of directobservation techniques to assess physical activity amongchildren and adolescents in defined areas. Both measures,developed at San Diego State University by Dr. ThomMcKenzie and colleagues, have helped us get objectivemeasures of physical activity in youth. SOFIT is used toassess the amount of physical activity occurring duringphysical education classes, or during any physicalactivity class setting (e.g., an aerobics or yoga class).SOFIT provides important information about the quality ofthe physical activity class by measuring not only theamount of physical activity the students are engaging induring class, but also the quality of specific classactivities and behaviors of the instructor. SOPARC is usedto measure physical activity and associated environmentalcharacteristics in park and recreational settings. Moreinformation on these two techniques can be found atwww.activelivingresearch.org.

Direct observation techniques can be very useful in manysituations. They are particularly helpful in identifying how people usedefined spaces (e.g., parks, playgrounds, bike lanes, sidewalks, andneighborhoods) for physical activity. Direct observation techniques,however, do have drawbacks. First, they can be relatively expensive,given the cost of training and employing observers. However, incertain parts of the world where labor costs are low, or volunteersare readily available, these methods are quite inexpensive, makingthem feasible and popular, often more so than device-basedmeasures. Second, the observer training is a very important aspect

of this technique. The investigator needs to be sure that what oneobserver calls moderate-intensity physical activity is the same aswhat the other observers are identifying as such. Further, thatdefinition cannot drift over time—that is, an exercise that is classifiedas vigorous intensity should be classified as such throughout thestudy. Direct observation techniques are not feasible whenassessing physical activity occurring throughout various settings(e.g., measuring participant activity both within a city and in aspecific park). Studies using direct observation methods must have aclear focus on the setting where the assessments will take placerather than on the individuals. For example, an organization may beinterested in diagnosing and improving the levels of physical activityoccurring in public recreation centers in low-income neighborhoods;SOPARC would be an excellent tool for measuring physical activityin such a project.

Would you do things a bit differently if you knew someone wereobserving or recording your physical activity behavior?

Finally, people’s behaviors often change simply because theyknow they are being observed or measured, as with consumer-based tracking devices or apps. That is, direct observation is highlyprone to participant reactivity. If you knew that your physical activityand exercise behavior were being monitored, do you think you mightalter what you do and how long or how intensely you participate?Most often, investigators try to observe physical activity in publicareas where observers are not identifiable. This anonymityminimizes reactivity and results in a better measure of physicalactivity behavior. Some investigators now use discrete webcams torecord activity at certain public spaces, and they code activity levelsfrom a computer. However, these practices are still being refined andhave raised ethical questions with respect to people’s right toprivacy. These important concerns should continue to be consideredas this field of research and new technologies advance.

SELF-REPORT INSTRUMENTSHistorically, the most frequently used techniques for physical activityassessment, particularly in studies of how physical activity andexercise influence health outcomes, have been based on self-report.Science based on self-report instruments has been able to show thatphysical activity greatly decreases (and physical inactivity greatlyincreases) a person’s risk of a variety of chronic diseases. Thisscience has also demonstrated the dose-response effect. Higherlevels of self-reported physical activity are associated with lower riskof disease outcomes. Part II of this textbook details some of thisevidence.

With self-report, study participants are asked to tell theinvestigators, either in interviews or via questionnaires or a diary,about their participation in physical activity, usually over a definedperiod. This period can be short (24 hours), a bit longer (the last 7 or30 days), or much longer (extending to the distant past). Theseresponses are then classified across the study population, andpeople are categorized based on their reported physical activity.

Analysis of such data can be done in a variety of ways, but is usuallyset up to examine exposure to physical activity (low amount vs. highamount, or low, medium, or high). This exposure, which is meant tobe an estimate of PAEE, can then be related to an outcome such asrisk of heart attack or osteoporosis.

THE 7-DAY PHYSICAL ACTIVITY RECALLAs with direct observation and diary techniques, physicalactivity interviews work best when the period of time isdefined. The 7-Day Physical Activity Recall is aninterviewer-administered questionnaire that has been usedfor many years in physical activity research (Blair et al.1985). The participant is asked first about the mostdistal day (i.e., seven days ago). The interviewer asksabout sleep time, sitting time, vigorous-intensityactivities (e.g., jogging and cycling), and moderate-intensity activities (e.g., walking). Each activityrecalled is probed for duration of participation. With thehelp of the interviewer, the participant reports allactivities in each of these categories. Light-intensityphysical activity (i.e., less than 3 METs) are inferredonce the other intensities have been assessed. Theinterviewer then proceeds to the next day and repeats theprocess. The protocol continues until the most recent(proximal) day. The data are then summarized and anestimate of PAEE, as well as TEE, is calculated based onthe reported activities, their duration, and theirfrequency. These interviews often take more than 45minutes to complete!

DIARIESPhysical activity diaries are essentially the same as any other type ofdiary. Study participants are asked to record their physical activitiesat various time points during the study. The idea is to develop aprotocol that maximizes recall and minimizes error—such as askingparticipants to record their physical activities immediately after they

occur or at bedtime. In this way, they are less likely to forgetmeaningful physical activities and their intensity, frequency, andduration. Personal trainers and coaches frequently use thistechnique to help exercisers and athletes understand and adhere totheir training regimens.

Diaries can be particularly helpful in understanding the contextand type of physical activity. Walking or bicycling to school, forexample, is often an important type of physical activity behavior tomeasure, and people—even children—can remember these eventsand record them in a diary. Beginning and ending times can berecorded in a diary to give the investigator an idea of the duration(and therefore the intensity). Diaries may also help investigatorsunderstand the behavior pattern (day-to-day variability) of people ina defined time period. The data gathered in physical activity diariescan be hard to summarize, however, particularly when studyparticipants keep diaries for extended periods.

INTERVIEWSInterviews have been used to measure physical activity in a varietyof settings. The person conducting the interview, after appropriatetraining, most often follows a predetermined interview protocol tolearn details about study participants’ physical activity behaviors.Memory cues and prompts are often used to aid in accuratereporting. For example, asking a person what time she went to sleepand what time she awoke the next day provides an excellentestimate of sleep time, or energy expenditure at or near BMEE. Agood interviewer can prompt the participant to provide informationthat otherwise may go unreported.

Interviews have several advantages. They are conducted bytrained personnel who can probe for items that participants may notreadily recall, which enhances the overall accuracy of themeasurement. They can be structured so that the context as well asintensity, frequency, and duration of the physical activities arereported. They also are not subject to the reactivity problem because

people are asked to recall the past—and the past cannot be alteredin any way that we know of!

Interviews can be expensive and have a substantial participantburden, however. Some interviews can take 30 to 45 minutes, andpeople sometimes struggle to remember even the broadest detailsabout days in the past. Studies have shown that recalls of moderate-intensity activities are much more prone to reporting errors than arethose of vigorous-intensity activities or rest (Pettee Gabriel et al.2010). Finally, interviewer training (or lack of it) can be a source ofsubstantial error. A good interviewer is essential for helping aparticipant remember details. A bad or inconsistent interviewer doesnot elicit the same response.

QUESTIONNAIRESThe final self-report method for physical activity assessment is theuse of questionnaires. Questionnaires can be administered directlyto participants (in person or on the Internet) or over the telephone aspart of a telephone survey. The difference between a self-administered questionnaire and one administered in a telephonesurvey or via an interview, as discussed earlier, is that the telephonesurvey administrator most typically follows a predetermined script.People who facilitate telephone surveys rarely, if ever, have thelatitude to probe and deviate from the script.

SELF-REPORT IN CHILDRENPhysical activity among children and adolescents is animportant concern for health, growth, and development.Children who are inactive are more likely than theiractive peers to grow up to be inactive adults. Manyattempts to assess physical activity in youth usingquestionnaires have been made over the years. Because of achild’s lack of awareness and inability to recall,

however, questionnaires generally are not recommended forchildren until the age of 12.

Questionnaires have evolved over the years as our understandingof the effects of physical activity on health outcomes has evolved.The earliest questionnaires asked respondents to reportoccupational physical activity. Job classifications and estimatedenergy expenditure in broad job categorizations were used toestimate PAEE. Very quickly, though, it became clear that anunderstanding of other domains of physical activity (includingtransportation, recreation, and household) were important, makingan understanding of occupational physical activity less of a prioritythan an understanding of the full range of physical activity.

Questionnaires are usually developed to assess physical activityexposure(s) of interest. For example, participants in a study of theeffectiveness of a training program could be asked about theirexercise habits (i.e., frequency, intensity, and duration) beforebeginning the program. The data from the questionnaire would besummarized and used in planning the training protocol of interest.

The time frame of interest is usually a critical component ofquestionnaire assessments of physical activity. This component alsopresents many difficulties in comparing results across studiesbecause many different time frames have been used, such as thefollowing:

Past three daysPast weekPast 30 daysA typical weekA typical month

Questionnaires have also been used to quantify physical activityin the distant past. This technique is particularly appealing for studiesof chronic diseases such as heart disease and cancers because itattempts to assess physical activity prior to the clinical manifestationof the disease. Because the biological influences of physical activity

on disease presumably occur over a long period of time, historicalrecall of physical activity can be very helpful.

DEVICES AND SELF-REPORT INSTRUMENTS: WHATDO THEY ACTUALLY MEASURE?Devices (such as accelerometers, GPS monitors, pedometers,and consumer-based wearables and smartphone apps), measuremovement. Meanwhile, self-report instruments (such asdiaries, interviews, and questionnaires) measurebehaviors. This is an important distinction. When a devicerecords acceleration and derives velocity, and thus energyexpenditure, it is not taking into consideration what theperson wearing the monitor is actually doing. Anaccelerometer may record a minute spent in moderate-intensity activity, but it cannot distinguish whether thatminute occurred in the middle of a walk to the bus stop orin a soccer game. If the device were replaced with aninterview, for example, the person may self-report havingplayed soccer for an hour and a half. This is theapproximate duration of a soccer match, so this amountseems reasonable, and gives us no reason to assume anysort of response bias. However, if this person had worn anaccelerometer during the soccer match, it is almostcertain that the accelerometer would not have recordedanything close to one and a half hours of continuousmoderate to vigorous physical activity. The bottom line isthis: Depending on the specific behavior (walking,running, bicycling, playing a particular sport), theamount of moderate- to vigorous-intensity physicalactivity recorded by a device can vary greatly from theamount reported by an individual.

Questionnaires and telephone surveys are cost-effective ways ofobtaining a substantial amount of physical activity and tracking dataon a large group of people. Questionnaires can be mailed, sentelectronically, or administered in a group format. The emergence ofhandheld technologies (smartphones and tablet computers) has

opened up a new set of opportunities for physical activityassessment using questionnaires and surveys. Questionnaires canbe written and implemented in multiple languages and can berepeated fairly easily over the course of a study. Questionnaires canalso be tailored for the specific purpose of the study and populationof interest (e.g., older adults, children, cardiac rehabilitationpatients).

Questionnaires for physical activity assessment do have somesubstantial drawbacks, however. Many of these relate to specifictypes of response bias, that is, when participants provide inaccurateresponses to surveys. Recall bias—the inability to accurately recall,or the selective recall of only certain activities—can substantiallyinfluence respondents’ answers to questions. The inability to proberespondents for more complete answers may result in many physicalactivities not being reported. Social desirability bias is another typeof response bias, and it refers to how people tend to respond to aquestion based on what they feel others expect or consider good. Ifyou were being probed about your physical activity habits, given thatyou know that physical activity is good and you feel that you shouldbe doing more of it, do you think you would be inclined to exaggerateyour responses? Also, the validity of the responses is always aquestion. Are respondents overestimating (or underestimating) theirbehaviors? Despite these challenges, questionnaires have taught usa lot about the relationship between reported physical activity andhealth and disease.

SURVEILLANCE IN POPULATIONSDisease surveillance has been a fundamental pillar of public healthat least since the era of the Black Death in Europe in the 14thcentury. During this time, fundamental health interventions(quarantine, determining an outbreak) were developed based oncounting the number of people affected by the deadly disease. Otherepidemics in subsequent centuries have led to more systematic datacollection of births and deaths and the emergence of vital statistics

systems. A plague in London in the 16th century led to thedevelopment and routine dissemination of the Bills of Mortality, thefirst known systematic system for collecting death information. Theseweekly summaries were used to map and monitor the extent of theplague in the city. In the next century, John Graunt famouslyconverted these simple counts of dead citizens to useful andinterpretable surveillance techniques in his work Natural and PoliticalObservations Made Upon the Bills of Mortality.

PUBLIC HEALTH SURVEILLANCEPublic health surveillance has been defined in the modern era as theongoing, systematic collection, analysis, and interpretation of health-related data. These data are meant to be used in the planning,implementation, and evaluation of public health practices, and theirinterpretation is meant to be disseminated to those responsible forprevention and control. Thus, surveillance is not merely thecollection and analysis of data; it also involves action on the part ofpublic health officials.

As population disease burdens have expanded over the yearsbeyond infectious diseases to include noncommunicable diseasesand their precursors, techniques and strategies for surveillance haveevolved to address these health issues. Public health surveillanceexpanded from counting deaths and cases of a certain disease tomonitoring those who may have been exposed to a certain diseaseand the trends and patterns of the disease in populations. It now alsoinvolves monitoring behavior and environmental exposuresregardless of disease status and policy and environmental correlatesof the risk of disease (USDHHS 2015 and 2016a). New techniqueshave also emerged as technology has advanced. Given thisevolution and expansion of public health surveillance, Declich andCarter (1994) proposed that it emerged as a new subdisciplineseparate from epidemiology.

PHYSICAL ACTIVITY SURVEILLANCE

Surveillance of physical activity is in its infancy relative to thesurveillance conducted on other important public health problems. Itsrecent emergence is likely partially due to the fairly recent union ofthe fields of kinesiology and public health to create the subdisciplineof physical activity and public health (Kohl et al. 2006). It is alsopartially due to the recent realization that a lack of physical activity isa major determinant of multiple noncommunicable diseases. Thisacknowledgment of the importance of physical activity to publichealth has resulted in the development and evolution of surveillancetechniques as our understanding of the dose and types of physicalactivity that promote health and prevent disease and disabilitybecomes clearer. Also of interest are determinants—individual andenvironmental—that promote physical activity (Kohl and Kimsey2009).

Different tools have been used in different countries and regionsto obtain country-specific surveillance data. Although these toolshave been helpful for the countries using them, the ability tocompare and contrast data between countries and populations hasbeen limited. Happily, major advances have been made toward astandardized tool for use around the world, in high-income as well asin low- and middle-income countries.

Internationally, two major developments have greatly assisted withthe population surveillance of physical activity behaviors. TheInternational Physical Activity Questionnaire (IPAQ) (Craig et al.2003) and the Global Physical Activity Questionnaire (GPAQ)(Bull et al. 2009) represent two responses to this question: Can aphysical activity surveillance system be developed to allowconsistent measures, within and between countries, of physicalactivity participation? The IPAQ, first developed in the 1990s, wasthe first to allow such consistent measures across countries; it hassince been used in more than 100 countries.

What proportion of adults in a population are active atrecommended levels? How many report regular walking? Do theseproportions vary by age, sex, or race or ethnicity? What are long-

term trends in these values over time? Is the population becomingmore active? Less active? Remaining the same? These are thekinds of questions physical activity surveillance systems can answer.These data are used to inform public health professionals and otherswho can plan strategies to make changes to improve the health ofpopulations. Some answers to these global physical activityquestions can be found in the special Lancet Series on PhysicalActivity I & II, published in 2012 and 2016, respectively (Hallal et al.2012; Sallis et al. 2016). These sets of publications, which representthe first attempt of quantifying the scope and burden of physicalinactivity worldwide, concluded that physical inactivity today shouldbe properly characterized as a pandemic (Kohl et al. 2012). Merriam-Webster Dictionary defines a pandemic as a disease or health factor“occurring over a wide geographic area and affecting anexceptionally high proportion of the population.” Findings from the2016 Lancet series report that about one-fourth of the globalpopulation is insufficiently active, and that little change has occurredat the global scale since 2012, reaffirming the notion of a globalpandemic of inactivity (Sallis et al. 2016).

POPULATION INDICATORS OF PHYSICAL ACTIVITYSurveillance data on physical activity provide a wealth of information—sometimes too much. The challenge of using these kinds of data isto find the correct indicator or indicators that best suit the purpose.Frequently used measures of interest from physical activitysurveillance are those associated with health outcomes.

Most physical activity surveillance systems provide data such asthe number of people in a population who participate in moderate-intensity and vigorous-intensity physical activity, the number ofpeople who meet physical activity guidelines, the prevalence ofspecific physical activities such as walking, and the prevalence ofsedentary behavior. Further, domain-specific surveillance becomesimportant for understanding the purpose for which physical activity istaking place. This helps us understand overall population-levels of

physical activity in context. For instance, two countries may have thesame levels of overall physical activity with the same proportion ofpeople meeting physical activity guidelines. However, in country A,most of the physical activity results from the transportation domain(i.e., people frequently walk or bike to get to and from places).Meanwhile, in country B, most of the physical activity comes fromleisure-time physical activity (i.e., exercising and playing sports isvery popular, but people do not frequently walk or bike to get to andfrom places). Being aware of this context is critical to understandingwhy some populations are very active and others are not, as well ashow to come up with large-scale solutions (investments in betterpublic transit infrastructure or in sports and exercise facilities) topromote physical activity among entire populations. The recentemergence of evidence-based physical activity guidelines hasgreatly helped define and standardize key outcome measures to usein physical activity surveillance systems.

Attention has recently turned to the role environment and policyindicators can play in physical activity surveillance. Characteristics ofthe social and built environment, as well as policies that support orinhibit physical activity, appear to be related to physical activitybehavior. Policies can include anything from state laws to supportthe training of physical education teachers (to increase capacity forphysical education) to local government actions to construct bicycle-friendly pathways that encourage active commuting. Chapter 15contains more discussion on physical activity policies, but questionsthat can be asked include the following: Does access to differenttypes of places in which to be active play a significant role? Are theremeasurable changes over time in the prevalence of these places?Examples of environmental indicators for leisure-time physicalactivity can include the location of and access to parks, trails, andother green spaces, recreation and fitness centers, and other placesto be active. On the other hand, environmental indicators fortransport-based physical activity could include location of and accessto transit stops, or availability and quality of sidewalks and bike

lanes. Legislative policies include mandates for school-basedphysical education and active-school-transport programs.

SOURCES OF PHYSICAL ACTIVITY DATAIn the United States, the ongoing surveillance of physical activitybehaviors of adults occurs in the CDC-run National Health InterviewSurvey (NHIS; USDHHS 2016b) and in the Behavioral Risk FactorSurveillance System (BRFSS; USDHHS 2016a). Periodic surveyssuch as the National Health and Nutrition Examination Survey(NHANES; USDHHS 2017) supplement our understanding. TheYouth Risk Behavior Surveillance System (YRBSS; USDHHS 2015)is used to monitor physical activity levels in high school students. Nophysical activity surveillance data are available for children youngerthan high school. Table 4.1, adapted from Carlson and colleagues(2009), highlights key data available from each of the three majorsources of adult physical activity surveillance in the United States. Inthe United States, another new source of physical activity data is the500 Cities Project, resulting from a joint effort between the NationalInstitutes of Health and the Robert Wood Johnson Foundation. The500 Cities Project database includes tabular and map data of theprevalence of physical activity participation at the city andneighborhood (census tract) levels.

Other countries also have substantial physical activity surveillancesystems that address the prevalence of physical activity andinactivity in those countries. A key challenge for establishing globalsurveillance systems of physical activity is standardizing the dataand indicators so that comparisons across countries are possible.Countries may use different instruments to collect surveillance data,although currently most use either IPAQ or GPAQ, which hasfacilitated international comparisons. The Lancet Series on PhysicalActivity and, more recently, the Global Observatory for PhysicalActivity (GoPA!), have led the way with the development and use ofstandardized indicators of physical activity to compare levels andprogress across countries. GoPA! is an excellent user-friendly

resource to explore global and country-specific trends in physicalactivity levels, research, and policies.

Finally, although most national surveillance systems are based onself-report instruments, it is becoming increasingly common amongcountries, especially high-income nations, to collect robustaccelerometer-based data among representative samples ofresidents to more objectively quantify the levels of physical activity ofthe country. There are at least five countries (United States, Canada,Norway, Sweden, Australia) that have collected accelerometer dataamong representative samples of adults at some point in time, andmany are starting to do it recurrently. However, the variation found indifferent data collection protocols and accelerometer brands, as wellas the cost associated with using these instruments in very largesamples, makes the global use of accelerometers for surveillancepurposes an ongoing challenge. Perhaps in the near future theemergence of new technologies and analytic methods will allow us toeasily and seamlessly collect objective physical activity data fromaround the world.

Table 4.1   Characteristics of U.S. Physical Activity AssessmentsCategory NHIS NHANES BRFSS

Surveyyearsphysicalactivitydata werecollecteda

1998-2016 1999-2017 2001, 2003, 2005,2016

Recallperiod

Respondent selectsrecall period, past12 months, past 2weeks, past weekb

Past 30 daysc

Usual weekdUsual week and past30 dayse

Self-reported

Yes Yes Yes

List ofspecificactivities

Not in first years;yes in recent years

Yes No

Assessesmoderate-intensityphysicalactivity

Yes, but includeslight intensity

Yes Yes

Assessesvigorous-intensityphysicalactivity

Yes Yes Yes

Whichintensitylevel isaskedaboutfirst?

Vigorous Vigorous Moderate

Definitionofmoderate-intensityphysicalactivity

Light sweating or aslight to moderateincrease in breathingor heart rate

Until 2006: lightsweating or a slightto moderate increasein breathing orheart rateAs of 2007: smallincreases inbreathing or heartrate

Small increases inbreathing or heartrate

Definitionofvigorous-intensityphysicalactivity

Heavy sweating orlarge increases inbreathing or heartrate

Until 2006: heavysweating or largeincreases inbreathing or heartrateAs of 2007: largeincreases in

Large increases inbreathing or heartrate

breathing or heartrate

Definitionof activebased ontheHealthyPeople2020objective

At least 150 minutesof light or moderateleisure-time activityper week, 75 minutesof vigorous activity,or 150 minutes perweek of an equivalentcombination ofactivity

At least 150 minutesof moderate leisure-time activity perweek, 75 minutes ofvigorous activity,or 150 minutes perweek of anequivalentcombination ofactivity

At least 150 minutesof moderate leisure-time activity perweek, 75 minutes ofvigorous activity,or 150 minutes perweek of anequivalentcombination ofactivity

Definitionofinactivebased ontheHealthyPeople2020objective

No reported light- tomoderate- orvigorous-intensityactivity for at least10 minutes

No reportedmoderate- orvigorous-intensityactivity for atleast 10 minutes

No reportedmoderate- orvigorous-intensityactivity for atleast 10 minutes

Abbreviations: BRFSS, Behavioral Risk Factor Surveillance System; NHIS, National HealthInterview Survey; NHANES, National Health and Nutrition Examination Survey.aIncludes years in which the same physical activity question was asked of respondents.NHIS asked a slightly different physical activity question in the first half of 1997, whichincluded a minimum duration of “at least 20 minutes.” This changed midyear in 1997 to “atleast 10 minutes” and has remained unchanged ever since.bIn early years, NHIS physical activity questions allowed respondents to select the recallperiod. To define physical activity levels, the average number of times per week (rounded tothe nearest time) was calculated for those respondents who selected monthly or yearly timeperiods. In more recent years, questions have shifted to defined recall periods, with somequestions asking about participation in physical activity over the past 12 months, the past 2weeks, or the past week (in most recent years).cNHANES collected data on past 30 days between 1999-2006.dAs of 2007, NHANES has used GPAQ to collect physical activity data. GPAQ asks aboutphysical activity in a “usual week” (7 days), and collects domain-specific physical activitydata for the recreational, transport, and occupational domains.eBRFSS has separate sections on physical activity in a usual week, as well as aboutmonthly participation (yes or no) in specific physical activities such as running, calisthenics,golf, gardening, or walking for exercise. The weekly module has not been included in everyiteration of BRFSS.Adapted by permission from S.A. Carlson et al., “Differences in Physical Activity

Prevalence and Trends From 3 US Surveillance Systems,” Journal of Physical Activity andHealth 6, Suppl 1 (2009): S18-S27.

COMBINING MEASUREMENT APPROACHES

Many ways of assessing physical activity exist, with no singleassessment recommended for every situation. Large studies thatfollow many people for long periods in order to track health problemsare likely to need self-report questionnaires to assess physicalactivity. Smaller studies of shorter duration that are interested inshort-term behavior changes resulting from a controlled interventionmay be best suited for relying on accelerometers as the primaryphysical activity assessment method. Characteristics of theenvironment and population under study all must be factored in tothe decision of which physical activity assessment technique to use.Each type has strengths and weaknesses that must be thoroughlyunderstood.

Ideally, combined approaches should be used to arrive at themost thorough estimate of physical activity. Strategies that combineself-report, direct observation, and device-based assessmenttechniques are becoming increasingly popular among researchteams, but challenges associated with data merging andstandardization remain. You should ask yourself some key questionsto help select a comprehensive set of tools and instruments for yourproject: What is the purpose of the project? Is it surveillance?Alternatively, do you want to determine the effect of a specificintervention among a specified group of individuals? Do you caremore about precision at the individual level or at the group level? Areyou interested in determining total levels of physical activity, or doyou want to know how much of it occurs for transportation versusrecreational purposes? Are you interested in all activity, regardless ofwhere it happens? Or, do you care about physical activity occurringin specific settings? Equally important, what resources do you haveavailable to conduct the study (your team of investigators and datacollectors, the equipment, space, and funds available)? Figure 4.5can help you determine which types of assessment methods arebest suited for your study.

Figure 4.5   Physical activity measurement instruments: balancingpracticality with precision.Based on G. Welk, J. Morrow, P. Saint-Maurice, Measures Registry User Guide: IndividualPhysical Activity. (Washington, DC: National Collaborative on Childhood Obesity Research,2017). http://nccor.org/tools-mruserguides/wp-content/uploads/2017/NCCOR_MR_User_Guide_Individual_PA-FINAL.pdf

LEADER PROFILEGeoffrey P. Whitfield, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?I was a master’s-level clinical exercise physiologistworking in cardiac rehabilitation. Although working withpatients was rewarding, I was more interested in theresearch that led to our clinical approaches. I had takena course in physical activity epidemiology as a master’sstudent, and kept in contact with my former professors.

During one of these conversations, I learned of a new PhDprogram starting in my hometown; I applied, and wasaccepted. It was a great fit, and very convenient for meand my family.

Did any one person have a major influence on your career?How?Perhaps the one person with the most influence, evenpreceding my academic advisors, was my wife, Mandy. Sheconvinced me to take the plunge to return to graduateschool, twice! She reminded me that time was going to passwhether I was in school or not, and that the benefitswould outweigh the cost of staying at a job where I wasnot 100% satisfied. As usual, she was wise beyond heryears.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?I’m very interested in how the environment shapes ourphysical activity behaviors, particularly our choicesaround transportation. I’ve been able to carve out a nichein understanding the current and emerging methods we useto monitor active transportation behaviors and theenvironmental elements that support these behaviors. I’mfortunate to be on a team that is tasked with performingthis exact mission.

Why do you do what you do?I do what I do because I appreciate the dramatic healthbenefits that physical activity can offer and want morepeople to be able to enjoy these benefits. I firmlybelieve that human adults are not naturally inclined to bevery active in our leisure time, and we need to besurrounded by environments and social norms that nudge ustoward activity. I feel privileged to work, in a smallway, toward this goal.

What are two key issues that must be addressed by 2030?First, continued improvement of methods to measure andcatalog the environmental elements that support walkingand other physical activities may help track progress. Forexample, we have clear national priorities for creatingwalkable environments, yet no comprehensive surveillancesystem exists to track the presence of sidewalks, a basic

element of walkability, across communities, states, or thenation.

Second, research into the impact of emerging mobilitytechnologies on physical activity may help predict futuretrends. For example, e-scooters may make it easier forpeople to choose an inactive form of transportation overwalking or bicycling (including bike share), especiallyfor first- and last-mile connections to public transit.Also, what will the emergence of autonomous vehicles(e.g., self-driving cars) mean for physical activity,including walking and bicycling for transportation? Whatwill people do with their time if they don’t have todrive?

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

There are many ways to assess physical activity. None areperfect, and all are subject to substantial errors inmeasurement.The total amount of energy expenditure due to physicalactivity is a small portion of the total daily energy expenditure.Domain-specific physical activity participation is important tomeasure so that the context of the behavior can beunderstood.The best way to assess physical activity is usually not withone instrument but with a set of instruments. The selection ofan instrument should take into consideration whether youwant to measure individuals or populations.Surveillance of physical activity is important for understandingtrends in participation over time in populations.Several sources of surveillance data exist in the UnitedStates and throughout the world.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

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Kohl HW III, Lee I-M, Vuori IM, Wheeler FC, Bauman A, Sallis JF.2006. Physical activity and public health: The emergence of asubdiscipline. Journal of Physical Activity and Health 3: 344-364.

Pandemic. 2019. Merriam-Webster.com. https://www.merriam-webster.com/dictionary/pandemic. Accessed July 16, 2019.

Pettee Gabriel K, James J, McClain JJ, Schmid KK, Kristi L, StortiKL, Ainsworth BE. 2010. Reliability and convergent validity ofthe past-week Modifiable Activity Questionnaire. Public HealthNutrition 14 (3): 435-442.

Sallis JF, Bull F, Guthold R, Heath GW, Inoue S, Kelly P, OyeyemiAL, Perez LG, Richards J, Hallal PC, Lancet Physical ActivitySeries 2 Executive Committee. 2016. Progress in physicalactivity over the Olympic quadrennium. The Lancet. 388(10051): 1325-1336.

U.S. Department of Health and Human Services. 2008. PhysicalActivity Guidelines for Americans. Washington, DC: U.S.Department of Health and Human Services.www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services. 2015. YouthRisk Behavior Surveillance System (YRBSS).

www.cdc.gov/HealthyYouth/yrbs/index.htm. Accessed 14 May2018.

U.S. Department of Health and Human Services. 2016a.Behavioral Risk Factor Surveillance System (BRFSS).www.cdc.gov/BRFSS. Accessed 14 May 2018.

U.S. Department of Health and Human Services. 2016b. NationalHealth Interview Survey (NHIS). www.cdc.gov/nchs/nhis.htm.Accessed 14 May 2018.

U.S. Department of Health and Human Services. 2017. NationalHealth and Nutrition Examination Survey (NHANES).www.cdc.gov/nchs/nhanes.htm. Accessed 14 May 2018.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2018. 2018 Physical ActivityGuidelines Advisory Committee Scientific Report. Washington,DC: U.S. Department of Health and Human Services.https://health.gov/paguidelines/second-edition/report/pdf/PAG_Advisory_Committee_Report.pdf .

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.1.3, 1.1.5, 2.1.2, 2.1.3, 2.2.3, 2.3.2, 2.3.3, 2.5.2,2.6.1, 2.6.2, 2.6.3, 3.2.1, 3.2.2, 3.7.1, 3.8.1, 3.8.2,4.1.3, 4.1.4, 4.2.1, 5.5.5, 5.5.6, 5.5.7, 6.2.1, 6.3.1,6.3.2, 6.3.5, 6.4.1, 6.4.2

PART IIHealth Effects of Exercise andPhysical Activity

CHAPTER 5Cardiorespiratory and MetabolicHealth

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The impact of sedentary behavior and sedentary activity inrelationship to physical activity and all-cause mortality

»  Cardiovascular disease risk factors, prevalence, andeconomic costs

»  The evidence of a correlation between physical activityand cardiorespiratory health

»  The physical activity and exercise recommendations forcardiorespiratory health

»  Metabolic diseases, their prevalence, and their risk factors»  The evidence of a correlation between physical activity

and metabolic health»  The physical activity and exercise recommendations for

metabolic health»  Testing methodologies used to predict and diagnose

cardiovascular and metabolic diseases

OPENING QUESTIONS»  What is the leading cause of death worldwide?»  How do metabolic diseases relate to the risk for developing

cardiovascular disease?

»  How much physical activity and exercise do people need todecrease their cardiovascular and metabolic health risks?

Part II of this textbook provides an overview of the scientific evidencethat supports the health benefits of participation in regular physicalactivity and exercise. It also reviews the potential health risksassociated with a lack of physical activity and exercise.

A primary benefit of engaging in physical activity and exercise isthat doing so significantly reduces the risk of premature death (i.e.,dying earlier than the average age of death for a specific populationgroup) from any cause, or all-cause mortality, as compared tobeing inactive (U.S. Department of Health and Human Services[USDHHS], Physical Activity Guidelines Advisory Committee[PAGAC] 2008, 2018). As noted in the first edition of Physical ActivityGuidelines for Americans (USDHHS 2008) and further supported bythe 2018 PAGAC, the effects of physical activity and exercise on all-cause mortality are remarkable for two reasons:

• Only a few lifestyle choices have as large an effect on mortalityas physical activity. It has been estimated that people who arephysically active for approximately 7 hours per week have a 30 to40% lower risk of dying early than those who are active less than 30minutes per week.

• It is not necessary to do high amounts of activity or evenvigorous-intensity activity to reduce the risk of premature death.Studies show a substantially lower risk of mortality when people doat least 150 minutes of moderate-intensity aerobic physical activity aweek.

The main messages to share are that (1) research clearlydemonstrates the importance of avoiding inactivity (sedentarybehavior and physical inactivity, see chapter 2) and (2) somephysical activity is much better than none at all, because there is adose-response relationship between the amount of physical activityand risk of poor health. Figure 5.1 illustrates the relationshipbetween the risk of all-cause mortality (reported in the 2008PAGAC), perhaps the ultimate indicator of poor health, and theminutes per week of moderate- or vigorous-intensity physical activityand exercise. As you can see, the risk of dying prematurely is lowerwhen one is physically active for 1.5 to 2.5 hours per week versus foronly 30 minutes per week. Moreover, the risk continues to declinewith higher amounts of physical activity. Thus, people who are moreactive are better off than those who are inactive or somewhat active.The 2018 PAGAC extended and supported the recommendations ofthe 2008 PAGAC by citing evidence from Moore and colleagues(2012) who extensively studied the effects of moderate-to-vigorousphysical activity and all-cause mortality in adults, aged 21-90, andfound the following:

1. The beneficial effect of physical activity has no lowest threshold.2. The slope is steepest at the lowest amounts of moderate-to-

vigorous physical activity.

3. At least 70% of the potential benefit on all-cause mortality isreached by achieving 8.25 MET-hours (150 min) per week ofmoderate-to-vigorous physical activity.

4. There is no obvious best amount.5. There is no apparent upper threshold.6. Benefits continue to accrue as more physical activity is accrued.7. Activity volumes of up to four times the 2008 guidelines (150-

300 minutes of moderate-intensity physical activity) show noevidence of increased mortality risk.

As you previously learned in chapter 2, sedentary behavior andphysical inactivity are inconsistent with promoting health forindividuals or populations. In 2016, Ekelund and colleagues notedthat lack of physical activity increases the risks of manynoncommunicable diseases such as type 2 diabetes, cardiovasculardisease, stroke, some cancers, and premature mortality. However,sedentary behavior also appears to be a potential risk factor formany chronic conditions and mortality. The authors conducted astudy that included over one million subjects in order to examine theassociations of sedentary behavior and physical activity with all-cause mortality. They concluded that increased sitting time isassociated with increased all-cause mortality; however, the level ofincreased risk with increased sitting time is reduced in physicallyactive people. Individuals who are active about 60 to 75 minutes perday in moderate-intensity physical activity seem to have noincreased risk of mortality, even if they sit for more than eight hoursper day. Thus, the current scientific evidence indicates lack ofphysical activity impacts all-cause mortality significantly more thansedentary behavior and sedentary activity.

Figure 5.1   The risk of dying prematurely declines as people becomephysically active.Reprinted from USDHHS, PAGA (2008).

The health benefits of physical activity and exercise (i.e., loweringthe risk of all-cause mortality) apply equally for men and women,adults of all ages, and active people of all body weights (normal,overweight, and obese), but there is insufficient evidence available todetermine whether these relationships vary by ethnicity orsocioeconomic status. This chapter addresses the specifics of howparticipation in physical activity and exercise has positive healtheffects related to cardiovascular health and metabolic health basedon updates in the relevant literature and the 2018 PAGAC.

According to the Physical Activity Guidelines Advisory CommitteeReport (USDHHS, PAGAC 2008, 2018), cardiovascular disease(CVD) and the underlying metabolic disorders (e.g., metabolicsyndrome and diabetes mellitus) can be prevented and treated withphysical activity. Although people can be independently diagnosedwith CVD, metabolic syndrome, or diabetes, all of these health

challenges can, and commonly do, occur together. People with thesediseases commonly have other chronic health issues and have notbeen physically active.

Cardiovascular diseases (CVDs) are a group of disorders of theheart and blood vessels that include the following:

Coronary heart disease (CHD or ischemic heart disease, heartattacks)Cerebrovascular disease (stroke)Elevated blood pressure (hypertension)Peripheral artery diseaseRheumatic heart diseaseCongenital heart diseaseHeart failure

Numerous risk factors (lifestyle or genetic variables that canpredict the occurrence of disease) are known to contribute to thedevelopment of CVD. In turn, many of these are modifiable withregular physical activity and exercise. Elevated blood pressure, poorlipid and lipoprotein profiles, low cardiorespiratory fitness, and highbody fat levels are but a few of these risk factors for CVD. To statethis another way, physical activity and exercise are thought to reducethe risk of CVD in two ways: (1) by reducing other risk factors for thedisease and (2) by playing a direct role in the physiological changesat the cellular level and in the blood vessels, the impairment of whichcontributes to CVD. Common respiratory disorders such as chronicobstructive pulmonary disease can also contribute to increased CVDrisk and decreased cardiorespiratory function, but are mostmodifiable by other interventions such as smoking cessation. Asnoted in chapter 2, regular physical activity and exercise can alsoimprove cardiorespiratory fitness, which can reduce CVD risk.

Metabolic risk factors contribute to a variety of conditions thatincrease the risk of CVD development. Metabolic syndrome is acluster of clinical characteristics that has been defined differently in

the past by several organizations (e.g., the U.S. National CholesterolEducation Program and the World Health Organization [WHO]), but ithas the following similar profiles in adults and adolescents:

Abnormal levels of lipids and lipoproteins (low high-densitylipoprotein [HDL] levels and high triglyceride levels with small,dense low-density lipoprotein [LDL], or atherogenicdyslipidemia)Elevated fasting glucose or insulin levelsHypertensionExcess abdominal obesity (USDHHS, PAGAC 2008; Alberti etal. 2009)

Diabetes mellitus (or diabetes) is a syndrome associated withlow insulin secretion, a limited ability of insulin to act on targettissues to maintain glucose homeostasis, or both of these conditions.Glucose is a main source of energy for the human body, and glucoselevels must be kept in equilibrium so the body’s metabolic processescan continue. Metabolic dysfunction (including some, if not all, of theconditions described for metabolic syndrome) is commonly seen inpeople diagnosed with diabetes. As discussed later in the chapter,CVD, metabolic syndrome, and type 2 diabetes can all be preventedor managed by engaging in appropriate, regular physical activity andexercise.

Diabetes can be further defined as type 1 and type 2. In peoplewith type 1 diabetes (the more rare of the two), the immune systemattacks and destroys the insulin-producing beta cells of the islets ofLangerhans in the pancreas. Type 1 diabetes is treatable with insulinand usually affects children and adolescents (it is also called juvenilediabetes or insulin-dependent diabetes), but it can occur in adultsafter a viral infection or as postgestational diabetes in women whobecome pregnant after age 35.

Type 2 diabetes (adult-onset, non-insulin-dependent diabetesmellitus, or NIDDM) is related to overweight, obesity, and insulinresistance (IR, impaired glucose homeostasis). In people with this

condition, the pancreas cannot secrete enough insulin tocompensate for the IR, which results in high blood glucose and highlipid levels. People with type 2 diabetes usually have the risk factorsassociated with metabolic syndrome, and they are at a higher risk fordeveloping CVD.

PREVALENCE OF CARDIOVASCULAR DISEASEAs a whole, CVDs are the number one cause of death globally. TheWHO (2017) reported CVDs as the cause of over 31% of all globaldeaths, and 17.9 million people died from CVDs associated withCHD and stroke (see Chapter 1). The leading causes of death (heartdisease, some cancers, stroke, and diabetes) have remained fairlystable since 2008, and participating in regular physical activity andexercise can decrease the risk of dying from all four.

Looking to the future, the WHO (2015) reported that the globalburden of CVD is most likely to continue. In 2015 an estimated 20million people died from CVD. This represents a monumental shift,as mentioned in chapter 1, away from infectious diseases andtoward chronic (noncommunicable) diseases as the leading causesof death. This also presents a terrific opportunity, given the positiveinfluence that physical activity has on many chronic diseases.

In addition to the health costs of CVD, there are economic coststo consider: individual and family health care, time lost from work,costs to government and industry for health care, and health carecosts to countries due to lost productivity. The American HeartAssociation (2017) estimated the direct costs (e.g., physician careand medications) and indirect costs (e.g., mortality and morbidity) ofCVD and stroke in the United States at $316.1 billion dollars for2012-2013. As a comparison, the cost of cancer in the United Stateswas $80.2 billion for 2015 (American Cancer Society).

RISK FACTORS FOR CARDIOVASCULAR DISEASENumerous CVD risk factors have been identified in the scientificliterature, many of which can be reduced by participating in regular

physical activity and exercise. The major risk factors for CVD aredivided between those that are modifiable (i.e., something can bedone about them) and those that are nonmodifiable (i.e., notchangeable).Modifiable Risk Factors for CVD

HypertensionAtherogenic dyslipidemiaTobacco usePhysical inactivityObesityMetabolic syndromeDiabetes mellitusElevated inflammation biomarkers (e.g., C-reactive protein)

Nonmodifiable or Less Modifiable Risk Factors for CVD

AgeSexHeredity (genetics)Ethnicity or race

The modifiable risk factors often can be significantly altered withlifestyle changes or pharmaceutical interventions. Nonmodifiable riskfactors are often regulated by behavioral interventions (e.g., physicalactivity and exercise) that influence molecular and cellular changesbased on individual or clusters of genes.

Even though these risk factors have been traditionally thought ofas binary (modifiable or nonmodifiable but not both), recent researchsuggests that this may not always be the case—that is, a person’sgenetic code for disease may actually be influenced by externalfactors such as physical activity and exercise. For example,engaging in regular physical activity and exercise appears to affectepigenetic markers (i.e., regulators of gene function) that cause the

down-regulation (repression) or up-regulation (enhanced expression)of specific genes. This in turn may influence the disease processes.In some cases a down-regulation of a gene or series of genes wouldreduce risk, whereas in other cases an up-regulation would beconsidered a positive effect. For example, if a person is at risk fordeveloping hypertension because both parents have the disease,participating in regular physical activity and exercise can lower thatperson’s hypertension and CVD risk, despite any geneticpredisposition.

Following are descriptions of the modifiable and nonmodifiablerisk factors for CVD:

• Hypertension. Hypertension is a major risk factor for stroke andother CVDs, especially if blood pressure is uncontrolled and >130/80mmHg (Whelton et al. 2017). Even somewhat elevated bloodpressure (120-129/<80) can indicate an increased risk of CVD.Hypertension exhibits few symptoms, but it is associated withheredity, aging, physical activity, diet, obesity, and alcoholconsumption. Hypertension is the most common, costly, andpreventable CVD risk factor.

• Atherogenic dyslipidemia. Elevated total cholesterol (>200mg/dl), high levels of LDL cholesterol (>100-130 mg/dl), low levels ofHDL cholesterol (<40 mg/dl for men and <50 mg/dl for women), andhigh levels of triglycerides are associated with greater risk for CVD.

• Tobacco use. Smokers have two to three times the risk for CVDthat nonsmokers have, and they tend to be less physically activethan nonsmokers. Quitting smoking reduces CVD risk and mayfacilitate greater participation in regular physical activity andexercise.

• Physical inactivity. Physical inactivity is a risk factor for CVDindependent of other risk factors.

• Obesity. A body mass index (BMI) >25 kg/m2 (overweight), or>30 kg/m2 (obese) increases CVD risk and is highly correlated tometabolic disorders.

• Diabetes mellitus. Diabetes mellitus doubles the risk ofdeveloping CVD compared to those without the disease. Blindness,limb amputation, and renal nephropathy are health problems thatarise when diabetes (type 1 or 2) is not controlled.

• Metabolic syndrome. Metabolic syndrome is identified as acluster of abnormal characteristics (see the preceding definition ofmetabolic syndrome) associated with prolonged sitting, poor diet,and sedentary behaviors. Generally three abnormal findings out offive would qualify a person for the metabolic syndrome (Alberti et al.2009).

• Elevated inflammation biomarkers. C-reactive protein (CRP) isone of several biomarkers and responses to internal systemicinflammation that have been found to be associated with thedevelopment of atherogenic plaques, plaque rupture, or both (i.e.,increased CVD risk).

• Age. Advancing age (men >40, women >50) is associated withincreased CVD risk because of changes in vascular health(vasodilation versus vasoconstriction with or without arterynarrowing) due to vascular stiffening.

• Sex. Men are at a higher risk for CVD than women at an earlierage; however, women’s risk for CVD increases significantlypostmenopause.

• Heredity (genetics). Genetics can account for 20 to 50% or moreof the variability in people’s CVD risk, which can predispose them toa lower or higher overall CVD risk. However, individual lifestyle andhealth behaviors can significantly reduce CVD risk.

• Ethnicity or race. Evidence supports the fact that some groupshave higher rates of CVD than others (e.g., African Americans havehigher stroke rates than other Americans). Contributing factors toethnicity and race may include socioeconomic status and stress.

CARDIORESPIRATORY HEALTH BENEFITS FROMPHYSICAL ACTIVITY AND EXERCISE

Physiological

Lower resting heart rate

Greater stroke volume

Increased O2maxIncreased ventilatory fatigue

Increased arteriovenous oxygen difference (AV O2 diff)(max)

Lower submaximal blood pressure

Increased lactate threshold (max)

Improved functioning of autonomic nervous system

Improved endothelial function

Reduced inflammation due to oxidative stress

Increased total energy expenditure

Increase in oxidative enzymes

Increase in anaerobic enzymes

Improved glucose homeostasis

Reduced body fat

Reduced waist girth

Increased muscular strength

Increased muscular endurance

Lower total cholesterol level

Increased HDL cholesterol level

Lower triglyceride level

Biomechanical

Improved economy

Increased motor skill and confidence to engage

further in physical activity and exercise

Improved proprioception, which helps coordination

system response and balance

Behavioral

Increased self-confidence

Improved self-efficacy

Decreased depression and anxiety

Experience with behavioral change

Improved stress management

Improved sleep patterns

Based on information from Physical Activity Guidelines Advisory Committee Report(USDHHS, PAGAC, 2008, and 2018), American Heart Association, American DiabetesAssociation, and the CDC.

KINESIOLOGY AND CARDIORESPIRATORY HEALTHA general understanding of several of the exercise sciences ishelpful for understanding the effects of physical activity and exerciseon health outcomes such as cardiorespiratory health. Recall fromchapter 2 that we are focusing on three key domains of kinesiologythat guide the health aspects of physical activity: exercisephysiology, the movement sciences, and the behavioral sciences.

The highlight box Cardiorespiratory Health Benefits From PhysicalActivity and Exercise contains some of the desired exercise-relatedadaptations in each of these three areas that positively influencecardiorespiratory health. Practitioners should be able to explain thecommon changes that can occur following participation in regularpersonalized or targeted population physical activity and exerciseprograms (refer to the Scientific Evidence and Guidelines sectionslater in the chapter).

Physical activity and exercise improve cardiovascular function bylowering resting heart rate and increasing stroke volume duringsubmaximal workloads. During moderate-intensity physical activity,comparing pretraining to posttraining workloads, most people havelower heart rates and blood pressures for the same amount of work.The muscles used for breathing (intercostals and abdominals)become more resistant to fatigue, and people can work for longer

periods. The maximal cardiorespiratory endurance ( O2max)increases along with the ability to extract oxygen for muscle activity(AV O2 diff).

The Fick equation, shown next, shows the central (pump function)and peripheral (muscle function) components of the cardiorespiratorysystem, and both parts can adapt specifically to provide increases incardiorespiratory capacity after conditioning. Maximal heart rate(MHR) and stroke volume (the squeeze of the heart with each beat,SV) make up the pump function components, whereas AV O2 diffrepresents muscle adaptations of increasing oxygen extraction:

O2max = (MHR × SV) × AV O2 diff

WHY IS THE FICK EQUATION IMPORTANT?Different types of physical activity affect differentparts of the circulatory system. For example, some people(e.g., those with heart disease) may not be able tostrengthen their heart as much as they can improve theirperipheral circulation (and therefore improve theirhealth). However, a healthy person should expect to seeimproved pump function (due to increases in SV) andimproved peripheral function (due to increases in AV O2diff).

MHR typically stays the same or decreases slightly with training(as a result of an increase in SV, the heart needs more time to fill);AV O2 diff also increases. The lactate threshold (LT) (i.e., point ofincreased lactic acid accumulation, which is associated withrecruiting more fast-twitch muscle fibers) typically improves from~50% of O2max to ~75% of O2max.

Reductions in the percentage of body fat are often observed overtime during physical activity and exercise training along withreductions in waist girth. The muscles used during aerobic activitiesshow improvements in strength and endurance (as compared to

baseline). Regular participation in physical activity and exercise isassociated with an improved atherogenic dyslipidemia profile thatincludes lower total cholesterol, increased HDL cholesterol, andlower triglyceride levels. Improvements in autonomic nerve function,increases in aerobic and anaerobic enzymes, improved glucosehomeostasis, improved endothelial function, and reducedinflammation related to oxidative stress are also commonphysiological adaptations observed with regular physical activity andexercise. Figures 5.2 through 5.4 illustrate common changes incardiorespiratory function after physical activity or exercise training.

Figure 5.2    Significant increase in O2max shown after one year of intensiveexercise training in an untrained person.Reprinted by permission from L. Kenney, J. Wilmore, and D. Costill, Physiology of Sport andExercise, 7th ed. (Champaign, IL: Human Kinetics, 2020), 269.

Figure 5.3   Some elite individuals have the genetic ability for strokevolume to continue to increase with exercise workload instead of plateauinglike most people.Reprinted by permission from L. Kenney, J. Wilmore, and D. Costill, Physiology of Sport andExercise, 7th ed. (Champaign, IL: Human Kinetics, 2020), 273.

Figure 5.4   Significant changes in heart rate after exercise trainingencompassing walking, jogging, and running.Reprinted by permission from L. Kenney, J. Wilmore, and D. Costill, Physiology of Sport andExercise, 7th ed. (Champaign, IL: Human Kinetics, 2020), 275.

Movement-wise, people who become physically active experienceimproved economy (i.e., a reduced oxygen–energy cost at a givenspeed or workload), which is a function of improved efficiency (this iscomplicated to actually measure). They also develop motor skills andoften gain more confidence to engage in future physical activity andexercise activities. Peripheral proprioception (i.e., the sense ofposition and movement) response and balance often improve aswell.

From a behavioral science standpoint, people undertakingphysical activity or exercise training likely experience several of thesteps of behavioral change (contemplation, preparation, action,maintenance, relapse) and learn to cope with the unique challengesof each step. By experiencing the stages of behavioral change,

people acquire coping skills and strategies that help them remain inthe maintenance stage for activity; they also avoid long periods ofrelapse as a result of overuse injuries, boredom, or lifestyle schedulechanges.

SECONDARY PREVENTION OF CVDDoes being physically active or participating in regularexercise help in the secondary prevention (like survivinga myocardial infarction [MI], or heart attack) of CHD andother atherosclerotic diseases? According to researchreported by the American Heart Association (AHA) and theAmerican College of Cardiology (ACC) the answer is, yes!The clinical practice of having cardiac patientsparticipate in multidisciplinary (including physicalactivity and exercise) cardiac rehabilitation programs hasbeen shown to stabilize, slow, or even reverse the naturalprogression of the underlying atherosclerotic process.Participation in exercise-based cardiac rehabilitationprograms within the first six months of a cardiac eventhas been shown to reduce total mortality for patients by20% and cardiac mortality by 26%.

Comprehensive cardiac rehabilitation includes baselinepatient assessments, risk factor interventions (smokingcessation, hypertension management, lipid management,diabetes management, and weight control), physicalactivity counseling and exercise training, nutritionalcounseling, psychosocial counseling, and vocationalcounseling. Cardiac rehabilitation programs havetraditionally included three phases with the followingobjectives related to physical activity and exerciseinterventions:

Phase 1 involves inpatient programming (2-3 days for

an uncomplicated MI) with education, baseline data

collection, identification of physical limitations,

and physical activity to avoid the negative effects

of prolonged bed rest and inactivity.

Phase II involves outpatient programming (4 weeks or

12 visits) that is often supervised in the clinical

setting, but can also be monitored via new

technologies from the patient’s home. Prior to

exercise programming, patients should be evaluated

with diagnostic graded exercise testing with

physician supervision and an exercise prescription

that may include clinical supervision. Most patients

are then encouraged to accumulate 30 to 60 minutes of

moderate- intensity aerobic activity, preferably all

days of the week, and they are encouraged to acquire

two days per week of resistance training.

Phase III usually involves voluntary patient

participation in outpatient programs like those at

local hospital-based fitness centers or YMCAs. In

Phase III cardiac rehabilitation programming (>12

weeks posthospital discharge), patients are

encouraged to at least maintain Phase II levels of

physical activity and exercise.

Phases I and II of cardiac rehabilitation programs areusually covered by personal insurance for a specifiedperiod of time or number of visits (e.g., 12 visits inPhase II cardiac rehabilitation). However, Phase IIIcardiac rehabilitation costs are covered directly bypatients. The safety of participating in medicallysupervised cardiac rehabilitation programs is welldocumented and has been shown to be safe and effectivewith only two fatalities reported in 1.5 million patient-hours of exercise. Unfortunately, only about 10 to 20% ofcardiac patients (approximately >2 million) participate incardiac rehabilitation programs yearly, which means thatmany individuals do not regain or achieve basic functionalhealth levels associated with higher levels of quality oflife.

Some additional health benefits of participation inregular physical activity and exercise that have beenreported for cardiac rehabilitation patients include:

greater exercise capacity, improved success when returningto work, improved cardioprotective mechanisms, reducedanxiety, improved self-esteem, and better overall qualityof life.

Adapted from AHA 2005 and AHA and ACC 2006.

Some people report that they feel better and have more self-confidence after several weeks of participation in physical activityand exercise. Many report experiencing lower levels of depressionand anxiety, and higher self-efficacy (i.e., personal accomplishmentand well-being) levels. Participation in physical activity and exercisehas been shown to be a very useful stress management tool andeffective for improving sleep patterns.

CARDIORESPIRATORY FITNESS ASSESSMENTSMany tests that require maximal or submaximal work levels havebeen developed and used by exercise physiologists and medicalspecialists to measure changes in cardiorespiratory fitness orfunction (CRF). The CRF measures and tests described herepromote cardiorespiratory health and the prevention of CVDs.People with a diagnosed CVD should seek clinical and rehabilitationadvice before undertaking physical activity and exercise programs.

When evaluating CRF, two helpful clinical measures to acquireare O2max and O2peak (the highest O2 uptake value or workloadobtained by a person without achieving true maximal criteria), whichrepresent valid measures or estimates of aerobic power (see chapter2 to review aerobic power and O2max). The percentage of O2maxis also important clinically and can be used to determine intensityover an extended time, or for bouts of physical activity and exercise.Exercise physiologists consider the measurement of O2max to beone of the single best predictors of overall CRF.

Graded exercise testing (GXT) is most commonly used tomeasure or estimate O2max (see www.acsm.org and figure 5.5 formore on GXT testing). The GXT protocol selection should be based

on target goals, physical abilities, and clinical considerations. Bydetermining a person’s O2max, a practitioner can calculate maximalworking capacity or absolute intensity (see chapter 2) and classifyphysical activity and exercise workloads accordingly (see figure 2.4).

Figure 5.5   Graded exercise testing.

Figure 5.6 illustrates the expected change in CRF (as measuredby O2peak) with increasing doses or volumes of physical activityand exercise. Of course, all changes depend on factors such asbaseline fitness, sex, age, BMI, and genetics.

Having determined the percentage of O2max that people canwork at for several minutes or for multiple short bouts throughout aday, practitioners can calculate their relative intensity as described inchapter 2. They can measure or estimate the percentage of O2maxby using any protocol that requires self-selected physical activity orexercise at moderate-to vigorous-intensity levels for 20 to 30minutes, or for three bouts of ~10 minutes per day.

Can CRF be estimated without a laboratory and a treadmill orwithout doing maximal testing? Yes it can, because significantpositive relationships exist among heart rate responses, speed ofwalking or running, and increasing workloads (resistance) withincreasing oxygen uptake and O2max. Several field assessmentscan be used as maximal or submaximal tests. Typically, maximaltesting (e.g., running on a treadmill to exhaustion) works best withlow risk, younger, healthy populations. Submaximal tests can beused with all populations except those with diagnosed CVD, those athigh risk for CVD, or those with orthopedic challenges who oftenrequire medical supervision for CRF evaluation (see ACSM [2018]for more on supervised exercise testing).

Figure 5.6   Changes in O2peak by exercise group.Reprinted from USDHHS, PAGAC (2008).

Distance run tests (1-mile run, 1.5-mile run, 12-minute run), the 1-mile walk, cycle tests, step tests lasting 3 to 5 minutes, andnonexercise prediction equations are all commonly used to predict O2max and have acceptable errors of <1 MET. It is also possible toestimate O2max using nonexercise protocols (e.g., questionnaires).The following commercial websites have listings of simplenonlaboratory CRF tests with procedures, online calculators, andinterpretation explanations that can make the assessment of CRFmore time and cost effective: www.exrx.net, www.brianmac.co.uk,and www.topendsports.com.

Once O2max has been estimated, an easy way to predict thepercentage of O2max at which a person can work is to use amethod first described by Ross and Jackson (1986). In this method,the person is asked to perform a 20- to 30-minute walk/jogevaluation that requires them to measure their heart rateimmediately upon completing the assessment. The followingequation can be used to calculate the percentage of O2max:

% of O2max = (heart rate in beats/min − k) × 100 / (220 − age −k)

in which k = 61 for males and 73 for females, and age is expressedin years.

An initial goal for many people would be to maintain ~50% of theirinitial O2max. A goal of ~75% is reasonable for those who want toimprove their CRF. By comparing the relative intensity that peoplecan maintain with the absolute intensity they can achieve,practitioners can help them achieve additional cardiorespiratoryhealth and performance goals.

GENERAL RECOMMENDATIONS FOR CARDIORESPIRATORYHEALTHAs shown in figure 2.3 the relationships between the risks of CHDand stroke, and the volume (frequency, bout intensity, time orduration, and longevity of the program) of physical activity andexercise, are dose dependent. Figure 2.3 shows that CHD risk dropsdramatically with moderate amounts of physical activity and exercisevolume, whereas the relationship for stroke risk is more of an Lshape and drops with a greater (but not too much) physical activityand exercise volume.

As early as 1961, an ad hoc committee of the AHA released areport that recommended that physical activity or exercise be part ofthe strategies to positively influence plasma lipid and lipoproteinlevels that can reduce the risks of heart attacks and stroke (Gotto1989). The report specifically stated that “overweight persons shoulddecrease their caloric intake and attempt to achieve a desirable bodyweight, and weight reduction should be facilitated by regularmoderate exercise.” The work of Mitchell and colleagues (McGuire etal. 2001) also supports the assertion that physical activity is veryimportant for the maintenance of cardiorespiratory capacity.

Today, over 50 years later, it is not surprising that many morerecommendations to engage in physical activity and exercise to

promote public health exist. The following section highlightsevidence-based recommendations from the PAGAC (USDHHS,PAGAC 2008, 2018) regarding the use of physical activity andexercise to improve cardiorespiratory health.

SCIENTIFIC EVIDENCEThe 2008 PAGAC cited strong scientific evidence that supports aninverse relationship between the volume of physical activity andexercise and incidences of CVD (CHD, stroke, hypertension, andatherogenic dyslipidemia). Regular physical activity and exerciseimproves cardiorespiratory fitness and lowers the risk for CVD, CHD,and stroke by 20 to 35%. The benefits of physical activity andexercise on cardiorespiratory health apply equally for men andwomen of all ages, and there was no evidence for racial or ethnicdifferences when adjusted for volume in the 2008 Report.

The 2018 PAGAC extensively reviewed 10 years of evidencesince the first PAGAC and provides more precision to the currentpublic health recommendations. The 2018 report focused on CVDmortality that included CVD in the broadest sense: stroke andischemic heart failure. The committee found the following:

Strong evidence demonstrates a clear inverse dose-responserelationship between the amount of moderate-to-vigorousphysical activity and all-cause mortality. The strength of theevidence is very unlikely to be modified by more studies of theseoutcomes.The relationship of moderate-to-vigorous physical activity andrisk reduction has no lower limit. Risk appears to continue todecrease with increased exposure up to at least three to fivetimes the amount of the lower bound of moderate-to-vigorousphysical activity recommended in the 2008 Guidelines (i.e., 150minutes per week). The new data are consistent with those usedto develop the 2008 Guidelines.

Strong evidence demonstrates that the dose-responserelationships between moderate-to-vigorous physical activityand all-cause mortality do not vary by age, sex, race, or weightstatus.Insufficient evidence is available to determine whether theserelationships vary by ethnicity or socioeconomic status.

The effective dose of physical activity and exercise forcardiorespiratory health in 2008 was reported to be at least 800MET-minutes per week (see chapter 2 to review the MET-minuteconcept) or 12 miles (19.3 km) per week (moderate intensity,vigorous intensity, or a combination). The public health target in the2008 Scientific Report was 500 to 1,000 MET-minutes of moderate-to-vigorous physical activity (or 150 to 300 minutes per week ofmoderate-intensity physical activity). The 2018 Committee supportsthe recommendations of the 2008 Report. Unfortunately, only halfthe U.S. adult population meets this level of physical activity. Thirtypercent of the population does no moderate-to-vigorous physicalactivity, even though major improvements in health can occur formany Americans with modest increases in regular physical activity.

Strong evidence was also found to support positive CRF benefitsfrom walking briskly for at least two hours per week and participationin aerobic activities in addition to the usual activities of daily living.The reduction of CVD risk begins to decrease once people dropbelow the dose threshold. Data to support the notion that anaccumulation of daily bouts of physical activity and exercise canlower CVD risk were limited in 2008, but people were encouraged toaccumulate multiple 10-minute bouts throughout the day. Evidencein the 2018 Report indicates that bouts of any length of moderate-to-vigorous physical activity contribute to the health benefits associatedwith accumulated volume of physical activity.

GUIDELINES

This section contains guidelines for physical activity participation tomaximize cardiorespiratory health. Special precautions are noted forpeople with diagnosed or preexisting CVD. For example, beginningan exercise program can be particularly dangerous for a person withuncontrolled hypertension. In this case, blood pressure should belowered by pharmaceutical intervention prior to participating in anyform of substantial physical activity. Once the blood pressure hasbeen controlled, physical activity can be added as part of themanagement regimen. The guidelines for cardiorespiratory healthcan be divided into three parts: children and adolescents (ages 6 to17), adults (ages 18 to 64), and older adults (>65 years).

Children and adolescents should acquire 60 minutes or more ofdaily physical activity and exercise for cardiorespiratory health. Mostof the 60 minutes should include either moderate- or vigorous-intensity aerobic physical activity or exercise. Youth should includevigorous-intensity physical activity or exercise at least three days perweek. They should also be encouraged to participate in physicalactivities that are appropriate for their age, are enjoyable, and offervariety. Table 5.1 contains examples of moderate-intensity andvigorous-intensity aerobic activities for children and adolescents,adults, and older adults.

Table 5.1   Examples of Moderate-Intensity and Vigorous-IntensityAerobic Physical Activity by Age Group

Population

Type of aerobic physical activity

Moderate intensity Vigorous intensity

Childrenandadolescents

Active recreation such as

hiking, skateboarding, in-

line skating (or canoeing for

adolescents)

Bicycle riding (stationary or

road biking for adolescents)

Brisk walking

Housework and yard work, such

as sweeping or pushing a lawn

mower (adolescents)

Games that require catching

and throwing, such as

baseball and softball

(adolescents)

Active games involving

running and chasing, such as

tag (or flag football for

adolescents)

Bicycle riding

Jumping rope

Martial arts, such as karate

Running

Sports such as soccer, ice

or field hockey, basketball,

swimming, and tennis

Cross-country skiing

Vigorous dancing

(adolescents)

Adults Walking briskly (3 mph, or

4.8 km/h) or faster, but not

racewalking

Water aerobics

Bicycling slower than 10 mph

(16 km/h)

Tennis (doubles)

Ballroom dancing

General gardening

Racewalking, jogging, or

running

Swimming laps

Tennis (singles)

Aerobic dancing

Bicycling 10 mph (16 km/h)

or faster

Jumping rope

Heavy gardening (continuous

digging or hoeing, with

heart rate increases)

Hiking uphill or with a

heavy backpack

Olderadults

The intensity of these activities can be either relatively

moderate or relatively vigorous, depending on an older

adult’s level of fitness.

Walking

Dancing

Swimming

Water aerobics

Jogging

Aerobic exercise classes

Bicycle riding (stationary or on a path)

Some gardening activities, such as raking and pushing a lawn

mower

Tennis

Golf (without a cart)

Adapted from USDHHS, PAGA (2008).

For substantial cardiorespiratory health benefits, adults should doat least 150 minutes (2 hours and 30 minutes) per week ofmoderate-intensity, or 75 minutes (1 hour and 15 minutes) per weekof vigorous-intensity, aerobic physical activity or exercise, or anequivalent combination of moderate- and vigorous-intensity aerobicphysical activity or exercise. Aerobic activity should be performed inepisodes of at least 10 minutes and preferably spread throughout theweek. For additional cardiorespiratory health benefits, adults shouldincrease their aerobic physical activity or exercise to 300 minutes (5hours) per week of moderate-intensity, or 150 minutes of vigorous-intensity physical activity or exercise, or an equivalent combination ofmoderate- and vigorous-intensity aerobic physical activity orexercise. All adults should avoid inactivity. Some physical activity isbetter than none, and adults who participate in any amount ofphysical activity or exercise gain some health benefits.

For substantial cardiorespiratory health benefits, older adultsshould follow the guidelines for adults, but consider the followingspecial situations:

When older adults cannot do 150 minutes of moderate-intensityaerobic activity per week because of chronic conditions, theyshould be as physically active as their abilities and conditionsallow.Older adults should determine their level of effort for physicalactivity relative to their level of fitness (see the discussion of theOMNI scale in chapter 2).

Older adults with chronic conditions should understand whetherand how their conditions affect their ability to do regular physicalactivity and exercise safely.

PREVALENCE AND ECONOMIC COSTS OF METABOLICDISEASEVarious sources estimate that over 1 billion people globally have thecluster of factors as described at the beginning of the chapterassociated with metabolic syndrome, and 422 million worldwide havediabetes (Mathers and Loncar 2006). About one-third of thosepeople are unaware of their condition because the early symptomsare mild. The prevalence of metabolic syndrome varies with thecurrent definition (Alberti et al. 2009), but it is estimated that between22.9 to 34% of the population in the United States have metabolicsyndrome (AHA 2017). The estimates for metabolic syndrome mayalso vary based on genetics, age, and ethnicity. As noted previouslyin the chapter, metabolic syndrome is associated with a cluster offactors, and researchers have found that these factors are consistentwith the dramatic increase in obesity, not only in the United States,but also globally. Cardiovascular disease and type 2 diabetes havebeen identified as primary clinical outcomes of metabolic syndrome,but those with metabolic syndrome are also at increased risk forother conditions such as hypertension, abnormal lipid levels, asthma,sleep disturbances (sleep apnea), and some forms of cancer.

In 2015, about 9.4% of the U.S. population was estimated to havetype 1 diabetes (5 to 10% of diagnosed cases) or type 2 diabetes (90to 95% of diagnosed cases) (CDC 2017). People with diabetes areat high risk for developing heart disease and stroke. Diabetes is theleading cause of adult blindness and kidney failure and causes 60%of nontraumatic lower-limb amputations each year (NationalDiabetes Education Program 2005).

In the United States, the prevalence of diabetes is higher amongHispanics, African Americans, and Native Americans than amongnon-Hispanic Caucasians. Figure 5.7 shows the prevalence of

diabetes in the United States in 1994, 2000, and 2015. Theprevalence of type 2 diabetes in children and adolescents has alsoincreased significantly in the past 10 years, which is alarmingbecause type 2 diabetes was rarely seen previously except inmiddle-aged adults.

The economic cost of metabolic syndrome is difficult to estimatebecause of varying methods of establishing a diagnosis (see nextsection). However, the estimated costs of diabetes in the UnitedStates in 2018 (ADA 2018) was estimated to be $327 million: $237million was related to direct diabetes care, and $90 million in lostproductivity. Another major economic challenge will be the futurecost of diabetes, because experts estimate that 84.1 million adults(age 18 and older) have prediabetes, which includes blood glucoselevels that are higher than normal but not high enough to indicate adiagnosis of diabetes.

Figure 5.7   Comparison of U.S. diabetes prevalence in adults for 1994, 2000,and 2015.Reprinted from Centers for Disease Control and Prevention (2017). Available:www.cdc.gov/diabetes/statistics

Table 5.2   Criteria for Clinical Diagnosis of Metabolic SyndromeRisk factor Criteria

Abdominal obesity (elevated waistcircumference)

Population- and country-specific

Triglycerides ≥150 mg/dl

HDL cholesterol

   Men <40 mg/dl

   Women <50 mg/dlBlood pressure ≥130/≥85 mmHg

Fasting glucose >100 mg/dl

Reprinted from NIH and NHLBI (2004); K.G.M.M. Alberti et al., “A Joint InterimStatement of the International Diabetes Federation Task Force on Epidemiology andPrevention; National Heart, Lung, and Blood Institute; American Heart Association;World Heart Federation; International Atherosclerosis Society; and International

Association for the Study of Obesity,” Circulation 120 (2009): 1640-1645.

METABOLIC DISEASE RISK FACTORSAs you learned earlier in the chapter, various risk factors areassociated with CVD as well as for metabolic syndrome and fordiabetes. Table 5.2 (Alberti 2009) outlines the criteria and the risksassociated with developing metabolic syndrome (three of five of therisk factors). Abdominal obesity is one of the metabolic risks that hasbeen recommended to be evaluated based on population differencesand ethnic groups.

The risk factors for diabetes are essentially the same as those formetabolic syndrome but also include the following:

Family history of diabetesEthnicity or race: Hispanics, African Americans, Asians, andNative Americans are at higher riskSedentary lifestyleHistory of CVD

The risk factors for metabolic syndrome and diabetes are closelyrelated to those for CVD. However, both physical activity and

exercise play a very important role in the prevention and treatment ofmetabolic syndrome and diabetes.

KINESIOLOGY AND METABOLIC HEALTHYou learned about the interrelationships of the exercise sciences,and the effects of physical activity and exercise on public healthoutcomes and cardiorespiratory health earlier in the chapter. Theexercise science–related adaptations that positively influencemetabolic health are basically the same as those listed in theCardiorespiratory Health Benefits From Physical Activity andExercise highlight box.

You should be able to explain the common metabolic changesthat can occur after participation in regular personalized physicalactivity and exercise programming (see Scientific Evidence andGuidelines sections). Following are specific metabolic adaptationsthat are expected as a result of physical activity:

Increased total energy expenditure (helps maintain energybalance)Improved protein synthesis rate and amino acid uptake intoskeletal muscleReduced low-density lipoprotein levelsReduced triglyceride levelsIncreased high-density lipoprotein levelsImproved glucose tolerance

One way to improve glucose uptake by skeletal muscles is toincrease the gene expression of GLUT-4, which is a protein that ismetabolically required for insulin to increase glucose uptake. GLUT-4levels increase with regular physical activity and exercise, and theydrop with physical inactivity and weight gain, which promotes insulinresistance.

Scientists have identified or are currently studying many othermechanisms associated with physical inactivity that can either initiate

or compound the effects of insulin resistance. By improving theirmetabolic health, people also benefit by achieving the behavioraland movement science–based changes associated with participatingin regular physical activity and exercise, which can improve theirfuture quality of life. Figure 5.8 shows the dose-response curves formoderate-to-vigorous physical activity and relative risk of type 2diabetes.

COMMON TESTS OF METABOLIC FUNCTIONPhysicians can evaluate patients for metabolic syndrome using thecommon clinical measures of blood glucose listed in table 5.2. Themeasurements of height, weight, girth, blood pressure, andmetabolic blood values are all part of most regular medicalcheckups. Although a diagnosis of metabolic syndrome does notnecessarily mean that the person has a clinical disorder (e.g.,dyslipidemia or diabetes), it does place the person at higher risk fordeveloping preventable chronic diseases.

Figure 5.8   Dose-response curves for moderate-to-vigorous physical activityand relative risk of type 2 diabetes. The relative risk for type 2 diabetesis significantly reduced with regular bouts of moderate-intensity physicalactivity.Reprinted from U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee, 2018 Physical Activity Guidelines Advisory CommitteeScientific Report (Washington, DC: U.S. Department of Health and Human Services), F5-24; Cloostermans et al. (2015); Wahid et al. (2016); Huai et al. (2016); Aune et al. (2015).

Can physical activity and exercise be fun while challengingcardiorespiratory and metabolic systems?

Fasting blood glucose concentration is a marker of short-termcontrol of glucose, and the glycosylated hemoglobin concentration isa marker of long-term regulation of glucose (glycosylatedhemoglobin is discussed in more detail a little later). Following arethree common tests used to diagnose diabetes or prediabetes (theyall require at least two tests conducted on separate days):

• Fasting plasma glucose (FPG) test. Blood glucose ismeasured after an eight-hour fast. If the glucose level is 99 mg/dl orbelow, the test is normal. A glucose level of 100 to 125 is consistentwith prediabetes or impaired fasting glucose; a person with theselevels is at higher risk for type 2 diabetes. If the level is 126 orhigher, the person has diabetes.

• Oral glucose tolerance test (OGTT). Blood glucose ismeasured after an eight-hour fast and two hours after ingesting 75grams of glucose dissolved in water. If the glucose level is 139 mg/dlor below, the test is normal. A glucose level 140 to 199 is consistentwith prediabetes or impaired fasting glucose. If the level is 200 orhigher, the person has diabetes.

• Random plasma glucose test. Blood glucose is measured(nonfasting) when a person has diabetic symptoms such asincreased urination, increased thirst, unexplained weight loss,fatigue, blurred vision, increased hunger, or sores that do not heal. Ifthe glucose level is above 200 mg/dl, the person probably hasdiabetes.

Many clinicians prefer the FPG test because it is convenient andinexpensive; however, the OGTT is more sensitive for diagnosingprediabetes. Gestational diabetes is also usually diagnosed with theOGTT.

During the 120-day life span of a red blood cell, glucosemolecules bind the hemoglobin contained within it, formingglycosylated hemoglobin. Once a hemoglobin molecule isglycosylated, it remains that way its entire life cycle. The percentageof glycosylated hemoglobin reflects the average level of glucose thatthe cell is exposed to during its life cycle. The species ofglycosylated hemoglobin measured clinically and reported ishemoglobinA1c (HbA1c). In healthy people, HbA1c is ~5%. Higher levelsof HbA1c (> 6.5%) are found in people with diabetes depending ontheir average blood glucose. Many guidelines recommend that HbA1cbe below 6% for most patients, which corresponds to an averageblood glucose of ~126 mg/dl.

GENERAL RECOMMENDATIONS FOR METABOLIC HEALTHFigure 5.9 illustrates the relationship between the risks of havingmetabolic syndrome and the amount of self-reported physical activityand exercise from several studies evaluating a dose-responserelationship (USDHHS, PAGAC 2008). As shown, metabolicsyndrome risk drops dramatically with moderate amounts of self-reported physical activity and exercise.

Figure 5.9   Dose-response relationship between self-reported physicalactivity and the risk of having metabolic syndrome.Reprinted from USDHHS, PAGAC (2008, p. G3-4).

Figure 5.10 illustrates the relationship between developingmetabolic syndrome and levels of measured physical fitness fromseveral studies evaluating a dose-response relationship (USDHHS,PAGAC 2008). Metabolic syndrome risk drops dramatically withmoderate fitness levels for adults.

Figure 5.10   Risk of developing metabolic syndrome and long-term physicalactivity levels, shown in four different research studies.Reprinted from USDHHS, PAGAC (2008, p. G3-6).

In 2004, Dr. John Holloszy (a research exercise physiologist andpublic health professional) of the Washington University School ofMedicine reviewed his career work of studying adaptations ofskeletal muscle mitochondria for the American College of SportsMedicine (Holloszy 2004). In his review paper, Dr. Holloszy statedhis belief that exercise deficiency is a serious public health problemwith regard to the development of chronic diseases and theaccelerated decline in the function of skeletal muscle,cardiovascular, and metabolic functional capacities with aging. He

further asserted that the most important area of future research is tofind effective ways to motivate “couch potatoes” to incorporateregular physical activity and exercise into their daily lives.

Evidence from the landmark Diabetes Prevention Program (2002)supports the lifestyle modification observations of Dr. Holloszy.Adults who were overweight and had prediabetes and who lost 7%of their body weight and were physically active 150 minutes perweek reduced their risk for developing diabetes by 58%. The sectionthat follows highlights recommendations from the PAGAC (USDHHS,PAGAC 2008) regarding the integration of physical activity andexercise science to promote metabolic health.

SCIENTIFIC EVIDENCEThe 2008 PAGAC reported strong and clear evidence that regularphysical activity improves the metabolic health of at least moderatelyactive people by 30 to 40% over that of sedentary people. Thebenefits of physical activity and exercise on metabolic health applyequally for men and women of all ages, and reasonable evidencesupports the association for various racial and ethnic groups.

In 2008, the recommended dose to improve metabolic health was120 to 150 minutes of moderate- or vigorous-intensity physicalactivity per week. However, evidence indicated that risk reductionswere starting to be seen at levels below 120 minutes per week inpeople who engage in leisure time physical activity (LTPA). Evidencethat resistance training was effective in treating diabetes was limited,although it did improve glucose control. It was noted at that time thatmore studies were needed to determine whether resistance trainingcan prevent type 2 diabetes. Limited data existed regarding theeffects of accumulated daily bouts of physical activity and exerciseon metabolic risk, as well as whether physical activity helps controlHbA1C or gestational diabetes.

The 2018 PAGAC confirmed the 2008 recommendations andexpanded the review of the scientific evidence. The 2018 PAGAC

reported the following with regard to physical activity and type 2diabetes:

• Strong evidence demonstrates a significant relationship betweena higher volume of physical activity and lower incidence of type 2diabetes.

• Strong evidence demonstrates that an inverse curvilinear dose-response relationship exists between the volume of physical activityand incidence of type 2 diabetes, with a decreasing slope at higherlevels of physical activity.

• Moderate evidence indicates no effect modification by weightstatus. An inverse relationship exists between a higher volume ofphysical activity and lower incidence of type 2 diabetes for peoplewho have normal weight, overweight, or obesity.

• Limited evidence suggests that the relationship between ahigher volume of physical activity and lower incidence of type 2diabetes is not influenced by age, sex, race, or ethnicity.

• Insufficient evidence is available to determine whether therelationship between physical activity and the incidence of type 2diabetes varies by socioeconomic status.

• Insufficient evidence is available to determine whether therelationship between physical activity and the incidence of type 2diabetes varies by the frequency, intensity, duration, or type ofphysical activity, or how physical activity is measured.

The 2018 PAGAC also studied the scientific evidence regardingbouts of high intensity interval training (HIIT; see chapter 2 for more)and the relationship between cardiovascular risk factors, weight loss,and metabolic profiles. The findings included the following:

• Insufficient evidence is available to determine whether a dose-response relationship exists between the quantity of high-intensityinterval training and several risk factors for cardiovascular diseaseand diabetes.

• Insufficient evidence is available to determine whether theeffects of high-intensity interval training on cardiometabolic risk

factors are influenced by age, sex, race, ethnicity, or socioeconomicstatus.

• Moderate evidence indicates that weight status influences theeffectiveness of high-intensity interval training to reducecardiometabolic disease risk. Adults with overweight or obesity aremore responsive than adults with normal weight to high-intensityinterval training’s effects on improving insulin sensitivity, bloodpressure, and body composition.

GUIDELINESThe guidelines for metabolic health are consistent with those forcardiorespiratory health for youth, adults, and older adults. However,people who may have metabolic syndrome or diabetes should takespecial precautions before undertaking physical activity or exerciseprograms.

Insulin concentration is an important determinant of the metabolicresponse to physical activity and exercise. The maintenance ofglucose homeostasis is critical for all people, and a normal responseto physical activity or exercise depends on exercise FITT (frequency,intensity, time and type) variables, fitness levels, nutritional state,and environmental factors. For those with diabetes, other factorssuch as the use of insulin or other medications and the temporalrelationship to eating are also important to consider during physicalactivity and exercise.

There are many ways to manipulate the timing and amount ofinsulin administration and food intake to avoid hypoglycemia orhyperglycemia. It is clear that a reduction in insulin dose inanticipation of exercise decreases the risk of hypoglycemia.

LEADER PROFILEWilliam E. Kraus, MD

Why and how did you get into the field of PhysicalActivity and Public Health?I have been involved in the exercise and health fieldssince 1980 when I was in medical school. I became involvedin the public health arena for the first time when I wasasked to be on the 2008 Physical Activity GuidelinesAdvisory Committee (PAGAC) in mid-2006.

Did any one person have a major influence on your career?How?Bill Haskell has been an informal career mentor since Ifirst got to know him in 1998. He has been a mentor in thecontext of my own science: dose-response effects ofphysical activity and exercise; how to run a guidelinesconsensus panel in physical activity and public health;and on mentoring in general.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?I have had the benefit of serving on both the 2008 and2018 Physical Activity Guidelines panels. My interest hasalways been how to balance public health and medicalresearch. Publishing the findings of the 2018 PAGAC panelin 2019 to increase dissemination of our research was agreat achievement for the field. I enjoy presenting atmeetings, locally and nationally, and explaining therationale behind our findings.

Why do you do what you do?I believe the evidence is overwhelming that physicalactivity is the best medicine and preventive approach fora myriad of human health conditions. I believe the best

thing I can personally do to help my fellow man is todevelop further evidence on this topic, share the findingswith the wider scientific and lay community, andincorporate these learnings into my own clinicalpreventive cardiology practice.

What are two key issues that must be addressed by 2030?

1. What is the role of light physical activity on publichealth?

2. What is the role of step-counting for physicalactivity monitoring for individuals and public health

recommendations, and can we come to consensus on step-

count recommendations for individual and public

health?

Table 5.3   Clinical Blood Glucose Levels for Active Insulin-Treated Clients

Metabolic control Blood glucose level

Normal blood sugar 80-100 mg/dl

Prediabetic 100-120 mg/dl

High blood sugar (hyperglycemia) >120 mg/dl

Low blood sugar (hypoglycemia) <70 mg/dl

Very low blood sugar (unconsciousness) <40 mg/dl

HbA1C < 7%

More specific recommendations on clinical blood glucose levels are available from theAmerican Diabetes Association (see www.diabetes.org).

People with type 2 diabetes who are not treated with insulin andwho do not have extensive vascular or neurological complicationscan generally exercise with no more concern than nondiabeticpeople of equal cardiorespiratory fitness. In addition to a preexerciseevaluation, blood glucose monitoring should be performed duringand after exercise to minimize the risk of developing hypoglycemia.

Added glucose ingestion prior to, during, or after exercise may bea more practical alternative to lowering insulin dose in the prevention

of hypoglycemia. Table 5.3 provides some metabolic controlguidelines for people who are active and insulin treated.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

As you previously learned in chapter 2, sedentary behaviorand physical inactivity are inconsistent with promoting healthfor individuals or populations. Current scientific evidenceindicates that lack of physical activity impacts all-causemortality significantly more than sedentary behavior andsedentary activity.Cardiovascular diseases (CVDs) are a group of disorders ofthe heart and blood vessels that include coronary heartdisease (CHD, heart attacks), cerebrovascular disease(stroke), raised blood pressure (hypertension), peripheralartery disease, rheumatic heart disease, congenital heartdisease, and heart failure. CVD is the number onepreventable cause of death globally.Metabolic syndrome refers to a variety of clinicalcharacteristics that were defined differently in the past byseveral organizations (e.g., the National CholesterolEducation Program and the WHO). However, most expertsnow agree that similar profiles are found in adults andadolescents, which include abnormal lipid levels (low high-density lipoprotein [HDL] levels and high triglyceride levelswith small, dense low-density lipoprotein [LDL] levels, oratherogenic dyslipidemia), elevated glucose levels,hypertension, and excess abdominal obesity.Research clearly demonstrates the importance of avoidinginactivity. The relative risk of dying prematurely is greatlyreduced when one is physically active for 1.5 to 2.5 hours perweek versus for only 30 minutes per week.

Personalized plans can be developed to minimize themodifiable and less modifiable risk factors for CVD andmetabolic syndrome to ensure future health.The physiological, biomechanical, and psychological benefitsof participating in regular physical activity and exercise oncardiorespiratory health are numerous.Determining O2max (or O2peak) and the percentage of O2max (or O2peak) by direct measures or by variousestimations can be helpful for evaluating cardiorespiratoryfitness or function (CRF).The effective dose of physical activity or exercise forcardiorespiratory health is 800 MET-minutes per week or 12miles (19.3 km) per week of moderate- or vigorous-intensityactivity. The 2018 PAGAC reinforced the findings of the 2008PAGAC and expanded the review of the scientific evidence.The Physical Activity Guidelines for Americans (USDHHS2008) state that youth need 60 minutes per day of aerobicphysical activity or exercise, and adults and older adults needa minimum of 150 minutes of moderate- and vigorous-intensity activities per week for cardiorespiratory healthbenefits.Metabolic syndrome affects over 1 billion people globally andrepresents a major future economic challenge related to thedevelopment of diabetes in the United States and the world.The risk factors for CVD and metabolic syndrome are closelyrelated and are positively affected by participation in regularphysical activity and exercise.Metabolic function can be evaluated with a standard clinicalblood test and other measures such as FPG, OGTT, andHbA1C levels.The effective dose of physical activity or exercise forcardiorespiratory health is 120 to 150 minutes per week ofmoderate- or vigorous-intensity activity.

The guidelines for metabolic health are consistent with thosefor cardiorespiratory health, but special precautions may beneeded for people who have diabetes and use insulin.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

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Whelton PK, Carey RM, Aronow WS, Casey DE Jr, Collins KJ, etal. 2017.ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and

management of high blood pressure in adults: Executivesummary: A report of the American College ofCardiology/American Heart Association Task Force on clinicalpractice guidelines. Hypertension 71 (6): 1269-1324.doi:10.1161/HYP.0000000000000066.

World Health Organization. 2011a. Global Status Report onNCDs.www.who.int/chp/ncd_global_status_report/en/index.html.Accessed 16 June 2011.

World Health Organization. 2011b. Milestones in HealthPromotion: Statements From Global Conferences.www.who.int/healthpromotion/milestones/en/index.html.Accessed 16 June 2011.

World Health Organization. 2017. Cardiovascular Diseases(CVD’s: Key Facts) https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds). Accessed 05 July2019.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.4.1, 2.1.1, 2.3.3, 2.5.2, 3.1.3, 6.1.3, 6.1.4, 6.2.1,6.2.2, 6.2.3, 6.2.4, 6.3.3, 6.3.5, 6.4.1, 6.4.2

CHAPTER 6Overweight and Obesity

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The definitions of overweight and obesity»  The classification of obesity as a disease or a health risk»  Caloric balance and the importance of physical activity

and exercise in achieving it»  The prevalence, economic costs, and risk factors of

overweight and obesity

»  The testing methodologies used to evaluate overweightand obesity

»  Evidence for a relationship between physical activity andenergy balance

»  Whether physical activity alone can prevent weight gain,result in weight loss, or keep weight off once it has beenlost

»  The impact of sedentary behavior and sedentary activity inrelationship to physical activity and weight status

»  The physical activity and exercise recommendations forachieving energy balance and a healthy weight

OPENING QUESTIONS»  What criteria are used to determine whether someone is

overweight or obese?

»  What evidence exists that suggests that physical activity canhelp with weight maintenance, weight loss, and the preventionof weight regain?

»  How much physical activity is consistent with weightmaintenance, weight loss, and the prevention of weightregain?

Other than tobacco use, obesity may be the most discussed anddebated public health problem in economically advanced countries.The prevalence of obesity has increased throughout the world; evenin countries in which undernutrition has been a recent problem,obesity is starting to take hold. Because it is such a visible conditionand because it affects so many people, it has taken a front seat inour health consciousness—perhaps due to its potential healtheffects, and perhaps for social reasons. Research in this area hasexploded; studies related to obesity address issues such as

genetics, behavior, and the environment. What makes someoneoverweight or obese? Why is this such a problem?

Overweight and obesity have been recognized as major healthproblems in the United States since 2001 (U.S. Department ofHealth and Human Services [USDHHS] 2001). The World HealthOrganization announced that worldwide obesity has nearly tripledsince 1975, and that most of the world’s population live in countriesin which overweight and obesity kill more people than underweight(WHO 2018). Overweight can be defined as carrying more body fatthan is healthy or an amount that increases disease risk. Obesitycan be defined as having an unhealthy body weight, which isconsistent with a variety of disease processes such as CVD,metabolic syndrome, and type 2 diabetes.

Are overweight and obesity diseases themselves? The answerdepends on the definition of disease and which professionalorganization, government office, corporation, or foundation youconsult. Overweight is not considered a disease, but has beenassociated with numerous health consequences, and althoughobesity has not been officially recognized as a disease in the UnitedStates, private and government insurance groups have beenreimbursing people classified as obese by physicians for specialfoods and weight loss programs and procedures since 2002.

How is obesity individually defined? As it turns out, this is not aneasy question because no perfect measure exists. Taller peopletypically weigh more than shorter people, men typically weigh morethan women, and younger people typically weigh more than olderpeople (at a given height). Moreover, statures are different indifferent cultures across the world. Clearly, body weight is difficult torely on for a definition of obesity. Later in this chapter, we will reviewkey ways to measure obesity, overweight, and body composition.

Body mass index (BMI) is a frequently used screening measurethat takes into account a person’s height as well as weight. The U.S.Centers for Disease Control and Prevention (CDC) advocate the useof BMI as a screening tool to determine the obesity status of adults

and children. To calculate BMI, divide weight in kilograms by heightin meters squared:

BMI = weight (kilograms) / height (meters2)Weight, BMI calculations, and classifications of underweight,

healthy weight, overweight, and obese are shown in table 6.1 foradults who are 5 feet 10 inches (178 cm) tall. A standard adultclassification indicates those with a BMI between 18.5 kg/m2 and24.9 kg/m2 are normal weight, and those with a BMI lower than 18.5kg/m2 are underweight. Adults with a BMI between 25.0 kg/m2 and29.9 kg/m2 are overweight, and those with a BMI 30 kg/m2 or greaterare obese. Above 30 kg/m2, there are several additionalclassifications: class 1 obesity is 30 to 34.9 kg/m2; class 2 obesity is35 to 39.9 kg/m2; and class 3 obesity is greater than 40 kg/m2.Currently, adults with class 3 obesity are considered at an extremelyhigh health risk and are generally eligible to be referred for surgicalintervention.

Table 6.1   Weight, BMI, and Status for a Sample HeightHeight Weight range BMI (kg/m2) Status

70 in. (178 cm) <129 lb (58.5 kg) <18.5 Underweight

129-174 lb (58.5-79 kg) 18.5-24.9 Normal

175-208 lb (79.3-94.3 kg) 25.0-29.9 Overweight

>209 lb (94.8 kg) 30 or higher Obese

Although BMI correlates with measures of body composition (e.g.,fat percentage, which is discussed later in the chapter), it does notdirectly measure body composition. BMI measurement does not takeinto account the specific components of body composition such aslean muscle mass versus fat mass. Therefore, a person with highamounts of lean muscle mass (e.g., an intercollegiate athlete) maybe misclassified as being overweight or obese using the BMI. This isa key limitation of using BMI, particularly at the individual level. BMIis not meant to be a clinical diagnostic tool. Rather, it is a useful

screening mechanism and can be helpful in a complete physiologicalhealth assessment.

The situation becomes even more complex when dealing withyouth. Children and adolescents mature at different rates; somemove through growth spurts early in their teens, whereas othersmature at a more gradual pace. For this and other reasons, standardBMI definitions for obesity in children and adolescents are different.Instead of a straight set of criteria (as with adults), the definition ofoverweight and obesity for youth is based on a relative scale.

Standardized growth charts are used to classify children andadolescents based on BMI. Growth charts consist of a set ofpercentile curves that illustrate various growth trajectories based ona standardized population. Percentiles are relative to a knowndistribution or population and are used as a standard against whichothers can be measured. Knowing sex, weight and height, and age,you can use a growth chart to estimate the percentile of BMI. Seefigures 6.1 and 6.2 for examples of BMI integrated into growthcharts. BMI calculators that can calculate youth BMI based on age,sex, height, and weight are available at many websites if youconduct an Internet search for youth BMI. Many adult BMI electroniccalculators are also available online.

POPULATION DIFFERENCESBecause of observed health risks (CVD and diabetes) inAsian and Pacific populations with BMI values lower than25 kg/m2, there have been attempts to advance the use ofcut points that are different than those developed largelyfrom Western populations. Of basic interest is a division

of the “normal” range (18.50 kg/m2 to 24.9 kg/m2) into twoadditional levels. Although the World Health Organization(WHO) does not officially endorse these different cutpoints (due largely to the variability in the scientificevidence), it does indicate that these lower values may beuseful to help people of these ethnicities in an advisorycapacity. Similarly, the International Diabetes Federation

has provided some general recommendations for cliniciansevaluating and identifying metabolic syndrome in variouspopulations, but other professional organizations havenoted differences in waist circumference cut points toidentify metabolic syndrome in different populations andethnic groups (Alberti et al. 2009).

Figure 6.1   CDC growth chart and BMI for age percentiles: boys 2-20.National Center for Health Statistics, Health, United States, 2016: With Chartbook on Long-term Trends in Health. Hyattsville, MD. 2017; in collaboration with the National Center forChronic Disease Prevention and Health Promotion (2000).

Figure 6.2   CDC growth chart and BMI for age percentiles: girls 2-20National Center for Health Statistics, Health, United States, 2016: With Chartbook on Long-term Trends in Health. Hyattsville, MD. 2017; in collaboration with the National Center forChronic Disease Prevention and Health Promotion (2000).

Following is a generally accepted classification scheme for BMIand weight status in children and adolescents:

Underweight: BMI less than the 5th percentile for age and sexHealthy weight: BMI between the 5th and 85th percentiles forage and sexOverweight: BMI between the 85th and 95th percentiles for ageand sex

Obese: BMI greater than the 95th percentile for age and sex

CALORIC BALANCEAs discussed in chapters 2 and 4, a basic understanding of energyexpenditure is essential for determining how physical activity andexercise can positively affect overweight, obesity, and theachievement of a healthy weight. Although the focus of this text is onenergy expenditure to achieve caloric balance, energy intake (i.e.,the food you eat) is clearly important as well.

A simple caloric balance equation scale is shown in figure 6.3. Forweight loss, all that is required is to create an energy deficit byconsuming fewer calories (i.e., eating less), expending more calories(i.e., being more physically active), or both. Sounds pretty easy.However, on further inspection (and in real life), it is clear thatachieving and maintaining energy balance is a complex state thatsome people never attain—and many cycle in and out of energybalance throughout their lives.

The 2015-2020 Dietary Guidelines for Americans (USDHHS,USDA 2015-2020) provides important guidance on energy intake forweight maintenance. For energy expenditure related to weightcontrol, guidance can be found in the two editions of Physical ActivityGuidelines for Americans (USDHHS 2008, 2018). These threereferences provide information about the variables in figure 6.3 suchas behavioral, social, cultural, and environmental factors and howthey affect caloric expenditure or increased energy storage.

The increase in the prevalence of overweight and obesity inchildren and adults worldwide clearly indicates that simple solutionsfor weight control are not working for a vast majority of people. And,although caloric restriction (i.e., dieting) alone can result in short-term weight loss and management, long-term solutions requirephysical activity increases and the maintenance of energyexpenditure for most to obtain and maintain a healthy weight as wellas to achieve other health benefits.

Figure 6.3   Energy balance equation. Please review chapter 4 for discussionof the thermic effect of food (TEF), basal metabolic energy expenditure(BMEE), and physical activity energy expenditure (PAEE).

Have you ever thought about how many kilocalories (kcals) youexpend per day in physical activity or exercise and how thatexpenditure affects your body weight and body composition?Although the energy cost of various physical activities (see part I) isknown, how can we determine how many calories (kcals) we need toexpend, individually or collectively, for effective weight management?Following is an important equation that we can use to answer thisquestion:

1 lb (0.45 kg) of fat = 3,500 kcalsTherefore, to lose 1 pound (0.45 kg) of fat, theoretically, you would

need to restrict or maintain your energy intake while expending morekcals in physical activity and exercise to the equivalent of 3,500kcals. This is not a perfect match because all the while you arebreathing, you are burning calories—albeit much more slowly than ifyou were exercising. A good rule of thumb is that, assuming a caloricintake of 2,500 to 3,000 kcals a day, burning 400 to 500 kcals eachday through physical activity, for many people, would be a usefulcontribution to the maintenance of a healthy weight. For normalweight people, this can be the rough equivalent of walking about 3miles (4.8 km) each day at a moderately intense pace.

Body composition is defined as the relative proportion anddistribution of fat, lean mass (muscle and bone), and minerals in thebody. An important outcome of participating in regular physicalactivity and exercise is that you can maintain or increase lean bodymass while controlling body fat levels (i.e., have a healthy bodycomposition), whereas with dietary-only interventions, lean mass isnot maintained.

Estimates of weekly physical activity and exercise caloricexpenditure levels, or physical activity energy expenditure (PAEE;see chapter 4), for healthy adults with varying levels of physicalactivity and exercise behaviors are shown in table 6.2.

The values in table 6.2 are based on data from table 2.4 inchapter 2, which shows that by simply meeting the minimumguideline for physical activity, substantially more kcals are expended(940 versus 190 at rest) by walking at 4 miles per hour (6.4 km/h) for150 minutes per week than by remaining sedentary. Jogging at 7miles per hour (11.3 km/h) for 300 minutes per week, to use anotherexample, will burn 3,930 kcals above sedentary levels, which is theenergy equivalent of more than 1 pound (0.45 kg) of fat (USDHHS,Physical Activity Guidelines Advisory Committee [PAGAC] 2008).

People starting a physical activity or exercise program should tryto achieve caloric balance by adjusting their food intake based on

their new energy expenditure levels and weight management goals.Some people may need to set their physical activity and exerciselevels above recommended levels to expend enough energy toachieve or maintain a healthy weight. Older adults also need toconsider that basal metabolic energy expenditure (BMEE) drops withage, making weight management more challenging and physicalactivity and exercise even more important for weight management.

PREVALENCE OF OBESITY AND OVERWEIGHT ANDASSOCIATED HEALTH CONSEQUENCESAs noted, the prevalence of obesity and overweight has increaseddramatically since the mid-20th century. Although anthropologicalstudies have shown that human populations have been gainingweight (on average) for centuries (due largely to improved nutrition),the tipping point from weight gain to obesity has been only a recentphenomenon.

Table 6.2   Expenditure Estimates (PAEE) by Duration andIntensity of Physical Activity

Duration of Physical Activity

Type of physical activity 150 min/wk (2.5 hr/wk) 300 min/wk (5.0 hr/wk)

Sedentary – sitting at rest 190 kcals 380 kcals

Walking (4 mph/6.4 km/h) 940 kcals 1,880 kcals

Jogging or running(7 mph/11.3 km/h)

2,155 kcals 4,310 kcals

Based on a 165 lb (75 kg) adult.

In the United States, the CDC (National Center for HealthStatistics 2017) reported that over 70.7% of people over the age of20 were overweight or obese. The WHO (2018) estimated in 2016that at least 1.9 billion adults over age 18 are overweight, and 650million throughout the world are obese. Because the humangenotype is resistant to short-term changes, it is clear that the globaland U.S. trends of increasing obesity are primarily due to external

changes (e.g., changes in the built environment and lifestyle factors).Figure 6.4 shows the obesity trends among adults from the CDCBehavioral Risk Factor Surveillance System for 1994, 2000, and2015 (USDHHS, CDC 2018).

Figure 6.4   Obesity trends among U.S. adults.Reprinted from National Health Examination Surveys II (ages 6-11) and III (ages 12-17);National Health and Nutrition Examination Surveys (NHANES) I-III; NHANES 1999-2000,2001-2002, 2003-2004, 2005-20063, 2007-2008, 2009-2010, 2011-2012, and 2013-2014.

The trend of an increasing prevalence of overweight and obesityamong children and adolescents over the past 45 years is alsodisturbing. Obesity trends among children and adolescents from1963 to 2014 (from the CDC’s National Health and NutritionExamination Survey data, National Institute of Diabetes andDigestive and Kidney Diseases 2017) are shown in figure 6.5. In theUnited States at least 18.5% of youth between the ages of 2 and 19years are obese. Among children ages 2 to 5 years, the prevalenceof obesity has increased to 13.9%; among children ages 6 to 11years, it has increased to 18.4%; and among adolescents ages 12 to19, it has increased to 20.6%.

Preventing childhood overweight and obesity is very challenging.Research has demonstrated that obese youth may be more likely tobecome obese adults than youth who are not obese. This situationincreases the risk of chronic, noncommunicable diseases such ashypertension, high cholesterol, and type 2 diabetes.

The CDC (2009) and others have reported that the prevalence ofobesity and overweight varies significantly among U.S. adults,adolescents, and children based on racial and ethnic differences. For

example, the CDC reports that non-Hispanic blacks had a 22%greater prevalence of obesity and Hispanics had a 25.8% greaterprevalence, compared to non-Hispanic whites. The results variedsomewhat by state, but were consistent across the United States.These findings support the important goals of the U.S. healthpromotion initiative Healthy People 2020 (USDHHS 2011), whichinclude reducing the prevalence of obesity in adults in the UnitedStates to 30.5% from 33.9% baseline (in 2005-2008) and eliminatinghealth disparities among racial and ethnic populations that contributeto obesity and overweight.

Interestingly, Wang and colleagues (2008) reported that if thecurrent U.S. overweight and obesity trends continue, by 2030, 86.3%of adults would be overweight or obese, and 51.1% would be obese.They also reported that African American women and MexicanAmerican men would be the subgroups most affected with rates of96.9% and 91.1%, respectively. The authors projected that by 2048,all American adults would be overweight or obese, and AfricanAmerican women would reach that level by 2030 if trends continueas they are. For children and adolescents, the prevalence of obesity(>95th percentile) will almost double by 2030 to about 30% overall.

The economic costs of overweight and obesity in the UnitedStates vary considerably based on how they are categorized andestimated. Obesity and overweight either directly contribute to thedevelopment of costly chronic disease processes, or they complicatethe medical treatments associated with managing the diseases oncediagnosed (or both). The estimated total costs for the United Statesin 1998 may have been as high as $78.5 billion (Finkelstein,Fiebelkorn, and Wang 2003), which included medical expenses forboth overweight and obesity. The economic costs (estimated at$81.5 billion in 2010) of obesity and overweight were predicted todouble every decade until 2030 and to eventually cost $860 to $956billion per year, which would account for 15.8 to 17.6% of total U.S.health care costs (Wang et al. 2008).

Figure 6.5   Obesity trends among U.S. children and adolescents.Reprinted from National Health Examination Surveys II (ages 6-11) and III (ages 12-17);National Health and Nutrition Examination Surveys (NHANES) I-III; NHANES 1999-2000,2001-2002, 2003-2004, 2005-20063, 2007-2008, 2009-2010, 2011-2012, and 2013-2014.

Data from Chenoweth and Leutzinger (2006) are illustrated infigure 6.6 and provide an example of the continuing economic costsof physical inactivity and excess body weight. The authors analyzedthe combined economic costs that physical inactivity and excessweight had on the U.S. economy in 2003 and the projected costs in2004 through 2008 with regard to direct medical care, workers’compensation, and productivity loss. If medical costs had continuedto rise as they had (10.2% per year), along with workers’compensation increases (4.5% per year) and productivity lossincreases (4.1%), and if levels of physical inactivity and excessweight prevalence had stayed the same, the projected total costswould have exceeded $708 billion in 2008. The work by Chenowethand Leutzinger (2006) presented conservative estimates of theactual economic costs and reflects the increasing costs associatedwith the current trends of physical inactivity and excess body weight.

Figure 6.6   Trends in economic costs due to physical inactivity and excessweight.Reprinted by permission from D. Chenoweth and J. Leutzinger, 2006, “The Economic Costof Physical Inactivity and Excess Weight in American Adults,” Journal of Physical Activityand Health 3, no. 3 (2006): 148-163.

OBESITY AND OVERWEIGHT RISK FACTORSThe risk factors for obesity and overweight are complex and difficultto understand because there is not just one cause. The risk factorsfor obesity are related to behavior, the environment, genetic factors,and their interactions. We all know very thin people who don’texercise at all and people who are obese or overweight who reportexercising frequently. The cause of obesity in two people is rarely thesame, and the cause(s) across populations vary in the same way.

HEALTH CONSEQUENCES OF OBESITYThe health consequences of obesity and overweight includethe following physical, psychological, and socialchallenges for adults, adolescents, and children:

Coronary heart disease (CHD)

Type 2 diabetes

Cancers of the endometrium, breast, and colon

Hypertension

Dyslipidemia (high total cholesterol, or high levels

of triglycerides)

Stroke

Liver and gallbladder disease

Sleep apnea and respiratory problems

Osteoarthritis

Gynecological problems (abnormal menses, infertility)

Source: 22 August 2015, www.cdc.gov/healthyweight/effects/index.html

A variety of factors that influence the caloric balance equation cancause people to eat too many calories, to not get enough regularphysical activity or exercise, or both, resulting in energy imbalanceand weight gain. The environment at home, school, work, and in thecommunity can provide numerous barriers and incentives that affectthe ability to achieve caloric balance and maintain a healthy weight.Genetics may predispose people to weight gain or obesity, but thelifestyles they adopt can help them achieve caloric balance and ahealthy weight based on their body type and body composition (seeCommon Assessments of Obesity and Overweight later in thechapter for more).Modifiable Risk Factors for Overweight and Obesity

Physical inactivityExcess caloric intakeLow socioeconomic status (SES)

Nonmodifiable Risk Factors for Overweight and Obesity

AgeHeredity (genetics)Ethnicity or raceCulture

Metabolism

Following are descriptions of the modifiable and nonmodifiablerisk factors for overweight and obesity:

• Physical inactivity. Inactivity creates a health cost versus ahealth benefit, and physical activity helps most people achieveenergy balance. Increased levels of physical activity and exercisehave been shown to improve long-term weight maintenance andenhance weight loss. Energy expenditure opportunities in modernsociety have been reduced as a result of technological advancesand environmental barriers. Examples include watching TV (morethan two hours a day) and excessive media use such as texting andsurfing the Internet.

• Excess caloric intake. When energy intake exceeds energyexpenditure, weight gain occurs.

• Age. Obesity and overweight problems increase for many asthey age because of the difficulty of achieving caloric balance whiledealing with the physical and mental challenges of normal aging.People who are homebound or living alone may be especiallysusceptible to weight gain.

• Heredity. Genes can affect factors such as metabolism, whichcan predispose a person to obesity or overweight, but researchshows that people can adjust their lifestyles and achieve caloricbalance and a healthy weight despite hereditary challenges.

• Race and ethnicity. Different race and ethnic groups havevarying prevalences of obesity. However, scientific studies have notrevealed whether the differences are due to genetic determinants orto social or cultural disparities.

• Socioeconomic status (SES). SES can provide major challengesto acquiring a healthy diet and to finding safe, affordableopportunities for engaging in physical activity or exercise.

• Culture. Cultural traditions (e.g., the built environment) andbehaviors can provide a variety of challenges to making positivelifestyle changes to achieve caloric balance and a healthy weight.

• Metabolism. A person’s resting metabolism (i.e., the rate ofcaloric expenditure at rest) can be affected by a variety of factorsincluding genetics, physical activity, diet, age, and medications.

OBESITY AND OVERWEIGHT CHALLENGESPhysical activity and exercise can affect energy balance related tocommon obesity and overweight challenges such as weight loss,healthy weight maintenance, the prevention of weight regain, andexcessive abdominal fat. Clinically significant weight loss hasbeen defined as at least a 5% loss of body weight (USDHHS,PAGAC 2008). Weight maintenance (or weight stability) has beendefined as a weight change of less than 3%, and prevention ofweight regain after a substantial loss that is consistent with achange in weight of 3% to less than 5%. The 2018 PAGAC reviewedrecent evidence for obesity and overweight challenges, and while thedefinition for clinically significant weight loss remains the same, acouple of updated terms and definitions were suggested: Bodyweight status is a concept encompassing issues related to weightgain, loss, and maintenance, and excessive weight gain is achange in body weight of more than 2 kg per year or 10 kg perdecade; or, a weight increase of more than 3%.

Fat is stored throughout the body. It can be found around theorgans (visceral fat) or near the skin (subcutaneous fat). Somepeople seem to store fat preferentially in one location over others.Men, for example, are more likely to store fat in the abdominal region(also called male pattern fat distribution), whereas women are morelikely to store fat in the hips, buttocks, and legs. Increased abdominalfat is associated with metabolic disorders including metabolicsyndrome (see chapter 5 for more on metabolic syndrome andphysical activity) more so than female pattern fat distribution.Research shows that abdominal fat loss is associated with increasedlevels of physical activity and is proportional to overall fat loss.

Engaging in regular physical activity and exercise, in and of itself,is not a panacea for losing weight, maintaining a healthy weight,

preventing weight regain, or decreasing abdominal fat. As describedearlier, many other factors influence caloric balance besides physicalactivity and exercise. Four points to help people achieve energybalance are (1) the concept of total energy intake; (2) interveningwith physical activity and exercise alone, diet only, or a combinationof diet and physical activity and exercise; (3) how nonactive leisuretime activities compete with active pursuits; and (4) the benefits ofengaging in regular physical activity and exercise other than justpreventing obesity and overweight.

Excessive energy intake has become a way of life because of theavailability of inexpensive, high-calorie foods that taste good. Thetrend of overconsumption correlates highly with the prevalence ofobesity and overweight; therefore, all weight management strategiesshould address diet. Numerous excellent resources that focus onhealthy eating can be found at www.nutrition.gov.

Physical activity and exercise are associated with caloricexpenditure, but these strategies used alone for weight loss, weightmaintenance, or the prevention of weight regain are not as effectiveas when they are combined with diet (energy intake) interventions.Figure 6.7 illustrates weight loss related to a diet intervention (caloricreduction), an exercise intervention, and a diet plus exerciseintervention. As you can see, physical activity and exercise are notsufficient for providing clinically significant weight loss. Figure 6.8illustrates the differences in BMI values between active and lessactive people; it suggests a dose-response relationship betweenphysical activity and exercise and BMI, supporting therecommendations of the 2018 PAGAC, which encourages adults toparticipate in 150 minutes or more of moderate- to vigorous-intensityphysical activity per week.

Figure 6.7   Weight loss related to a diet intervention, an exerciseintervention, and a diet plus exercise intervention.Reprinted from USDHHS, PAGA (2008).

Figure 6.8   Differences in BMI values due to level of physical activity.Reprinted from USDHHS and PAGAC (2008, p. G4-7); adapted from Kavouras et al. (2007).

KINESIOLOGY AND BODY WEIGHTChildren, adolescents, and adults can experience the positiveexercise-related adaptations associated with regular participation inphysical activity and exercise that can help with weight loss, healthyweight maintenance, the prevention of weight regain, and the loss ofexcessive abdominal fat. The combined benefits of physical activityand exercise listed in the highlight box Adaptations to FitnessProgramming Related to Body Composition can help variouspopulations improve their health and quality of life.

COUNSELING FOR WEIGHT MANAGEMENTEfforts to increase caloric expenditure with physicalactivity and exercise can be impeded with competition from

all of today’s labor-saving attractions (computers, cellphones, and other electronic media) that impede activediscretionary time activities. Strategies to help peopleoptimize the leisure time they spend being active can behelpful. Good advice would be: Choose the active choice!

Physiologically, participation in regular physical activity can helppeople lose weight and achieve a healthy weight, or get closer toachieving caloric balance. These basic changes can lead toincreases in muscular endurance and O2max levels, which result inimproved functional health (i.e., people can do more work beforefatiguing).

Physical activity and exercise can also help people reduce totalbody fat, waist circumference, and intra-abdominal fat; maintain orincrease lean muscle mass; and prevent the regaining of weight lost.Ultimately, participation in physical activity and exercise can lowerthe risks for such chronic disease processes as type 2 diabetes,metabolic syndrome, and CHD, as well as orthopedic challengesassociated with obesity and overweight.

Although the associations are not well understood at this time,overweight and obesity are often linked with multiple factors thatnegatively affect restful sleep. For example, people who suffer fromobstructive sleep apnea (OSA), restless leg syndrome (RLS), andinsomnia and who become physically active experience reducedsymptoms. Numerous studies have shown that physical activity andexercise are associated with increases in sleep duration and qualityof sleep (especially delta sleep). These sleep improvements canhelp people get a good night’s rest and be active and ready to go thenext day without the usual chronic fatigue associated with problemssuch as OSA. The loss of upper abdominal fat, which can beachieved by becoming physically active, is also associated withreduced respiratory problems such as OSA.

ADAPTATIONS TO FITNESS PROGRAMMING RELATEDTO BODY COMPOSITIONPhysiological

Increased muscular endurance

Increased O2maxImproved caloric balance

Improved metabolism

Lower percentage of body fat

Smaller waist circumference

Less intra-abdominal fat

Maintenance of or increased lean muscle mass

Maintenance of or loss of weight

Biomechanical

Improved economy

Improved balance

Improved mobility

Improved proprioception

Behavioral

Increased self-confidence

Improved self-efficacy

Decreased depression and anxiety

Increased motor skill

Experience with behavioral change and increased

confidence to engage further in physical activity and

exercise

Biomechanically, improved economy of movement can beexpected with weight loss and the maintenance of a healthy weight.Improved economy of movement is a function of improved efficiency,

which is directly related to body weight and body composition,particularly in weight-bearing activities. Losing weight or achievingweight stability can allow people to perform motor skills moreefficiently as a result of increases in range of motion, which is limitedby carrying excess weight or body fat. Improved biomechanicalfunction also inspires confidence to engage in future physical activityand exercise activities. Peripheral proprioception (i.e., sense ofposition and movement) response, which is associated with balanceand fall prevention, often improves as well.

Weight loss and weight stability also have strong psychologicaleffects. Experiencing the unique challenges of the phases ofbehavioral change (contemplation, preparation, action, maintenance,relapse) gives people coping skills and strategies for achieving andmaintaining a healthy weight. In addition, people who have lostweight or succeeded at maintaining a healthy weight experiencemore self-confidence, greater feelings of self-efficacy, and lowerlevels of depression and anxiety.

COMMON ASSESSMENTS OF OBESITY AND OVERWEIGHTCommon assessments of obesity and overweight provide estimatedbody composition values such as the percentage of body fat, leanmuscle mass, and total body fat. Everyone needs some fat tomaintain normal bodily functions. Essential fat is important forstored energy, cushioning and insulation, and vitamin absorption; it isfound in and around the nervous system, heart, lungs, kidneys,spleen, intestines, and muscles. The minimal amount of essential fatfor men has been estimated to be 3% of body weight; for women theestimate is around 12% of body weight. When essential body fat fallstoo low, health risks for chronic disease and adverse immunereactions increase.

Ideal body fat and ideal body weight are terms that have beenused to describe the hypothetical optimal percentage of body fat orbody weight. The values for ideal body fat and ideal body weight,however, are highly variable and should be based on factors such as

age, sex, personal goals, behaviors, and appropriate educationalmessaging that does not promote addictive disorders (i.e., eating orexercise). However, most men are considered obese if they arecarrying ≥28% body fat, and most women, if they are carrying ≥32%(Jackson and Ross 1997).

The simplest way to assess body composition is visual inspection.If one’s BMI (discussed earlier) is already higher than normal andthere is weight gain and no regular physical activity and exercise,that person is probably carrying too much body fat. Although many ofus have noticed visually that we were gaining weight and weretherefore motivated to try to lose weight, we did not have quantitativedata (e.g., percentage of body fat, amount of lean muscle mass) tohelp us set goals and gauge our success. Body compositionassessments, described next, provide the quantitative informationnecessary for setting weight management goals and evaluatingprogram outcomes.

The highlight box Common Methods for Measuring BodyComposition lists laboratory-based and field tests that exercisescientists use to measure body composition. See figure 6.9 forphotos illustrating skinfold testing and dual-energy X-rayabsorptiometry.

Magnetic resonance imaging (MRI) and computedtomography (CT) are currently recognized as the gold standard (orbest available with minimal error) techniques for measuring bodycomposition. However, because of the expense of these techniques(about $1,000 USD per scan, or $1,000,000 USD for the purchase ofa scanning device), they are mainly used in research and as medicaldiagnostic tools. Both of these techniques rely on X-ray technologyto quantify the amount of fat tissue and other tissue in the body or ina region of the body. MRI is thought to be a safer technique largelybecause it does not rely on ionizing radiation.

Dual-energy X-ray absorptiometry (DXA) full body scans aremore affordable than MRIs and CTs, but the device can beexpensive. Many exercise physiologists now regularly use DXA in

the assessment of body composition. Scanning is done while aperson is still and supine on a table; X-ray beams are emitted anddata are differentiated into fat mass, fat-free mass, and skeletal(bone) mass in a two-dimensional display. The DXA technique canprovide precise data about a person’s percentage of body fat, as wellas bone mineral density data. The DXA technique usually has anerror of about 1% compared to MRI and CT measures for full bodyscanning, but it can be less accurate if the scan does not include thewhole body.

Figure 6.9   Body composition measures: (a) skinfold testing and (b) dual-energy X-ray absorptiometry.

Underwater (or hydrostatic) weighing is based on the principleof water displacement (i.e., when you get in tub of water, the waterlevel rises based on the volume your body displaces). In thistechnique, a person’s weight is measured both in and out of water. Aperson with more fat (which is less dense than lean body tissue) willbe buoyed up more than a leaner person, and will consequentlyweigh less underwater. To minimize measurement errors, hydrostaticweighing requires motivated subjects and additional laboratoryequipment that can be used to measure residual lung volume (RV). IfRV is estimated (as is often done) and not measured, large errors inmeasurement can result. A hydrostatic tank system costs about$10,000 to $15,000 USD and requires regular maintenance.Hydrostatic weighing used to be considered the gold standard forbody composition measurements and has been traditionally used,

but the technique has a measurement error of 2 to 3% compared toMRI, CT, and DXA.

Air displacement plethysmography (i.e., the measurement ofchange in volume) determines volume and density, and has becomea popular technique used at universities and by many sport teams. Acommon tool for this technique is the commercially available BODPOD. This technique, based on the same displacement principles ashydrostatic weighing, uses multiple sensors in the measurement unitto measure air displacement in a known period of time. Body fat isthen calculated based on those data. Air displacementplethysmography is relatively easy to use, but the devices areexpensive (about $35,000 USD) and not readily available. Comparedto the MRI, CT, and DXA techniques, this technique has about a 3%measurement error.

Skinfold measurement has been used by exercise scientists andclinicians for many years to estimate body composition based onpopulation-specific and generalized equations. Measuring skinfoldthickness at various sites on the body (e.g., the tricep, abdomen, andthigh) provides an estimate of subcutaneous fat (about 50% of totalbody fat) and therefore an estimate of body density and thepercentage of body fat. Using the equations developed by Jacksonand Pollock (1978, 1980), the percentage of body fat can beestimated from the sum of skinfold thickness, age, and sex. Skinfoldcalculators can be found at websites such as www.exrx.net. Skinfoldmeasurements correlate well with hydrostatic weighing measures,but have at least a 3% error rate.

COMMON METHODS FOR MEASURING BODYCOMPOSITION

Visual inspection

BMI

Magnetic resonance imaging (MRI); computed tomography

(CT); dual-energy X-ray absorptiometry (DXA)

Hydrostatic weighing

Air plethysmography

Skinfold measurement

Bioelectrical impedance analysis (BIA)

Circumferences (waist and hip)

Bioelectrical impedance analysis (BIA) sends a low-amperageelectrical current through surface electrodes on the body (e.g., thewrist and ankle). Measurements of the resistance to the currentpermit the estimation of body composition using predictionequations. Tissues of different densities conduct electricity atdifferent rates, and thus body composition can be estimated. TheBIA technique can be highly variable based on the following factors:

Quality of the BIA instrument usedFluid balance (normal hydration or dehydration) of the subjectRecent food consumptionEffects of recent bouts of physical activity and exercise

The cost of BIA instruments ranges from $100 to several thousanddollars (USD); the more expensive models provide better measureswhen subjects’ hydration levels are controlled (about 3% error rate).Some simple BIA instruments (e.g., bathroom scales) predict thepercentage of body fat based on BMI, but they have about a 6%error rate.

Waist circumference measures have become common ways todetermine when people are carrying too much abdominal fat forgood health. For waist circumference, it is generally recommendedto measure girth at the level of the lowest rib or umbilicus level usinga cloth measuring tape with a spring-loaded handle that costs about$15 to $20 USD. Waist circumferences are measured in inches or

centimeters. Adults should have waist measures of ≤40 inches (102cm) for men, and ≤35 inches (89 cm) for women (Kenney, Wilmore,and Costill 2015).

Waist circumference values for children and adolescents (ages 2to 18 years) have been published (Fernandez et al. 2004) and areexpressed as percentile ratings by age, sex, and ethnicity (AfricanAmerican, European American, and Mexican American). Youth canbe classified by waist girth as being in the 10th through 90thpercentile. Although there is no professional consensus on an idealwaist circumference measure for youth because of growth anddevelopment issues, it is reasonable to encourage youth to maintaina girth close to the 50th percentile.

Waist circumferences can be used in combination with youth BMImeasures to clarify higher-than-expected BMI measures (e.g., inathletic youth with high levels of muscle mass). For example, if ayoungster has a high BMI and a high waist measurement (>90thpercentile), she should not be encouraged to gain more weight. Ayoungster with a low BMI (<5th percentile for age and sex) and lowwaist measurement should not be encouraged to lose more weight.

The waist-to-hip ratio (WHR) is another simple way to usecircumferences to evaluate the distribution of body fat in adults.Health risk increases as WHR increases, and standards vary by ageand sex. According to the guidelines of the American College ofSports Medicine (ACSM 2018), young adult men and women shouldhave ratios of lower than 0.95 and 0.86, respectively, to becategorized as having a low health risk. Older adult men and women(ages 60 to 69 years) should have ratios of lower than 1.03 and 0.90,respectively, to be classified as having a low health risk.

PHYSICAL ACTIVITY GUIDELINES FOR A HEALTHY WEIGHTFor many adults, obesity is associated with significant increases inabdominal fat that increase the risk for metabolic syndrome and type2 diabetes (see chapter 5). Regular participation in aerobic physicalactivity and exercise can decrease total body fat and abdominal fat,

and these changes are consistent with improved metabolic function.Generally, the greater the volume of physical activity or exerciseacquired by individuals or populations, the greater the reductions inbody and abdominal fat.

For children and adolescents, the prevention of excessive weightgain during maturation is critical to prevent obesity and overweight inadulthood. Unfortunately, recent public health surveys note that theparents of many at-risk children are not aware of the problem or donot recognize that their children are overweight. Recent U.S. nationalpolicy statements targeting pediatricians and other health careproviders assert that children and adolescents who are overweight orobese in their early teens should be identified as early as possibleand given some sort of weight management plan through theintervention of parents, teachers, coaches, and family physicians.

One of the most obvious influences on weight management ishow people perceive their ideal weight or physique. Researchfindings indicate a great disparity between reasonable weight loss orweight gain goals and people’s “dream weight.” Even though somepeople may not reach their goal weight, they will likely report positivephysical, social, and psychological benefits from any weight loss.The following scientific evidence and guidelines can help individualsand populations establish realistic goals for weight management(e.g., achieving a healthy weight) and meet their specific needs (e.g.,weight loss, weight stability, prevention of weight regain, or loss ofexcessive abdominal fat) through regular participation in physicalactivity and exercise.

SCIENTIFIC EVIDENCEThe 2008 PAGAC noted physical activity (150 minutes per week to≥300 minutes per week) was associated with modest weight loss,prevention of weight gain following weight loss, and reductions intotal and regional adiposity. Evidence that resistance training helpedwith weight maintenance was not as strong, given that resistance

training increases lean muscle mass, and the volume of resistancetraining regimes was usually less than that for aerobic training.

Can a walking program be effective for weight managementwithout diet control?

The 2018 PAGAC expanded the review of the evidence availablein 2008, and focused on weight maintenance and weight gain withinnormal BMI limits (18.5 to < 25 kg/m2) for adults in relation toparticipating in 150 minutes per week or more of physical activity.The 2018 report also reviewed the impact of sedentary behavior andsedentary activity in relationship to physical activity and weightstatus. The specific 2018 PAGAC findings regarding weight gainwere:

Strong evidence demonstrates that the significant relationshipbetween greater time spent in physical activity (≥300 minutesper week) and attenuated weight gain in adults is observed withmoderate-to-vigorous physical activity.Moderate evidence indicates that the relationship betweengreater amounts of physical activity and attenuated weight gainin adults does not appear to vary by sex.

Limited evidence suggests a dose-response relationshipbetween physical activity and the risk of weight gain in adults,with greater amounts of physical activity (150 minutes per week)associated with lower risk of weight gain.Limited evidence suggests that the relationship between greateramounts of physical activity and attenuated weight gain in adultsvaries by age, with the effect diminishing with increasing age.The evidence from studies of older adults, however, isinconsistent.Insufficient evidence is available to determine whether therelationship between greater amounts of physical activity andattenuated weight gain in adults varies by race and ethnicity.Insufficient evidence is available to determine whether therelationship between greater amounts of physical activity andattenuated weight gain in adults varies by socioeconomic status.Insufficient evidence is available to determine whether therelationship between greater amounts of physical activity andattenuated weight gain in adults varies by initial weight status.Insufficient evidence is available to determine an associationbetween light-intensity activity and attenuated weight gain inadults.

The 2018 PAGAC concluded the following with regard to theimpact of sedentary behavior and sedentary activity for adults inrelationship to physical activity and weight status:

Limited evidence suggests a positive relationship betweengreater time spent in sedentary behavior and higher levels ofadiposity and indicators of weight status.Limited evidence suggests the existence of a direct, gradeddose-response relationship between greater sedentary behaviorand higher levels of adiposity and indicators of weight status.Insufficient evidence is available to determine whether therelationship between sedentary behavior and weight status

varies by age, sex, ethnicity, socioeconomic status, or baselineweight status.Insufficient evidence is available to determine whether therelationship between sedentary behavior and weight statusvaries by amount of moderate-to-vigorous physical activity.Insufficient evidence is available to determine whether bouts orbreaks in sedentary behavior are important factors in therelationship between sedentary behavior and weight status.

As mentioned earlier in the chapter, regular physical activity andexercise are also important to prevent and control obesity andoverweight in children and adolescents. The 2008 PAGAC foundstrong evidence demonstrating that higher levels of physical activitywere associated with multiple beneficial health outcomes, includingcardiorespiratory and muscular fitness, bone health, andmaintenance of healthy weight status in children and adolescents(ages 6-19). The 2018 PAGAC focused on expanding the review ofliterature since 2008 with the addition of studies on children 3-6years of age. The additional scientific recommendations of the 2018PAGAC for youth were as follows:

Strong evidence demonstrates that higher amounts of physicalactivity are associated with a reduced risk of excessiveincreases in body weight and adiposity in children ages 3 to 6years.Limited evidence suggests that greater time spent in sedentarybehavior is related to higher weight status or adiposity inchildren and adolescents; the evidence is somewhat stronger fortelevision viewing or screen time than for total sedentary time.Insufficient evidence is available to determine whether therelationship between physical activity and health effects inchildren younger than 6 years of age is moderated by age, sex,race, ethnicity, weight status, or socioeconomic status.

GUIDELINES

The physical activity guidelines for youth and adults regarding weightcontrol are the same as for other health outcomes with one notableexception. The guidelines recommend that preschool-aged children(ages 3 through 6 years) should be physically active throughout theday to enhance growth and development, and adult caregivers ofpreschool-aged children should encourage active play that includesa variety of activity types. Children and adolescents shouldparticipate in 60 minutes of moderate- or vigorous-intensity physicalactivity daily to maintain a healthy weight.Adults (and older adults) who are trying to control their weight shouldinclude dietary considerations, and they should follow the 2015-2020Dietary Guidelines for Americans to learn more about weightmanagement and how to determine a healthy weight. Many adultswill achieve caloric balance and lose weight if they meet the minimalphysical activity and exercise guidelines of acquiring 150 minutesper week of moderate-intensity physical activity, 75 minutes perweek of vigorous-intensity physical activity, or a combination of both,and two days of bone-strengthening and muscle-strengtheningactivities.

LEADER PROFILEAdriano Akira Hino, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?I have practiced judo since I was 9 years old, so physicalactivity and sport were part of my childhood andadolescence. It was not hard to figure out that I wantedto be a physical education professor. I don’t know exactlywhat made me take the track of Public Health, but I thinkit was a natural progression from my personal interestsand my curiosity. I always wanted to understand behaviors,and epidemiology gave me the perfect tool to do it. SinceI started working with epidemiology, Public Health hasmade sense.

Did any one person have a major influence on your career?How?Definitively yes. I have had the opportunity to work withvery good researchers since I was an undergrad student, somy path is filled with professors who had a huge influenceon my career. There is not enough space to mention alltheir names; however, I need to acknowledge CiroRodriguez-Añez, Rodrigo Reis, and Olga Lucia Sarmiento whowere especially important to my career. They taught meeverything I know today and gave me the chance to work onhigh-level research projects and to meet the mostimportant researchers in the field. These teachings andopportunities were key components that led me to where Iam today, professionally and personally.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?I have two main interests at this moment in my career. Thefirst one is to better understand how the environment canaffect physical activity. The second one is to betterunderstand how evidence can be used during the decision-making process. We already have evidence of interventionsthat work to promote physical education, but they haven’tbeen enough to increase physical activity levels. Thus,dissemination and implementation is an area that I willinvest considerable time working on during the upcomingyears.

Why do you do what you do?

I believe it is because my work can have an impact onpeople’s health.

What are two key issues that must be addressed by 2030?In terms of physical activity and considering the contextof my country (Brazil), I would say that reducing physicalactivity inequalities is a key issue that must beaddressed by 2030. The second issue is the importance ofincluding evidence-based research in the decision-makingprocess of health and physical activity promotion. Thiswould bring the researchers and the decision makers closertogether and increase the likelihood of more effectiveinterventions.

Given the effect of body weight on both energy expenditure andenergy intake, the minimal physical activity guidelines may not beenough in some cases to create an energy deficit or balance. Thus,for weight control, 150 minutes per week of moderate-intensityphysical activity, 75 minutes per week of vigorous-intensity physicalactivity, or a combination of both, should be step one. Adults whowant to lose a substantial amount of weight (more than 5% of bodyweight) and those who are trying to maintain their weight after asignificant weight loss may need to do more than 300 minutes perweek of moderate-intensity activity to meet weight-control goals.

Older adults may have physical disabilities that limit the intensityat which they can engage in physical activity and exercise, makingweight loss more of a challenge than it is for younger adults. Thephysical activity guidelines stress that older adults (as well as youthand adults 18 to 65) should remember that caloric expenditureresults from engaging in all types of physical activities, and not justexercise. For example, taking short walks throughout the day andmaking active choices such as taking the stairs instead of theelevator expends calories and can be helpful in weight control ascompared to remaining sedentary. Older adults who can engage invigorous physical activity or exercise may find that this strategy ismore effective (time efficient) for weight control than working at

lower-intensity activities for more time. In any case, older adultsshould try to participate in regular physical activity and exercise thatis sustainable and safe.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

A basic understanding of energy expenditure and caloricbalance is essential for a more detailed understanding of therelationships between exercise and physical activity, andoverweight and obesity.BMI is a common measure to classify adults and youth asobese, overweight, normal weight, or underweight.The prevalence of obesity and overweight is at pandemiclevels in the United States and globally for youth and adults.By 2030, if obesity prevalence levels in the United States donot change, the economic costs will reach 15.8 to 17.6% oftotal U.S. health care costs.The health consequences of obesity include CHD, type 2diabetes, cancer, hypertension, dyslipidemia, stroke, liver andgallbladder disease, sleep apnea and respiratory problems,osteoarthritis, and gynecological problems.The environments at home, school, work, and in thecommunity provide numerous barriers and incentives toachieve caloric balance and maintain a healthy weight.Genetics may increase the predisposition for weight gain orobesity, but a healthy lifestyle can help people achieve caloricbalance.Physical activity and exercise are associated with caloricexpenditure, but using these strategies alone for weight loss,healthy weight maintenance, or the prevention of weight

regain is not as effective as combining them with diet (i.e.,energy intake) interventions.The physiological, biomechanical, and psychological benefitsof participating in physical activity and exercise on obesityand overweight are numerous and achievable for mostpeople.Common laboratory-based and field tests used to measurebody composition are visual inspection, BMI, MRI, CT, DXA,hydrostatic weighing, air plethysmography, skinfoldmeasurement, BIA, waist circumference, and waist-to-hipratios.Engaging in regular moderate- to vigorous-intensity physicalactivity for more than 150 minutes per week can help manyadults achieve energy balance, weight loss, weightmaintenance, and the prevention of weight regain afterweight loss, as well as reduce abdominal fat. However, somepeople may require more activity (≥300 minutes).Positive changes in youth body composition have beenassociated with at least 30 minutes per day of regularmoderate- to vigorous-intensity physical activity.Everyone should try to follow the recommendations in thePhysical Activity Guidelines for Americans to achieve andmaintain a healthy weight.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYAlberti KGMM, Eckel RH, Grundy SM, Zimmet PZ, Cleeman JI, et

al. 2009. Harmonizing the metabolic syndrome: A joint interimstatement of the International Diabetes Federation Task Forceon Epidemiology and Prevention; National Heart, Lung, andBlood Institute; American Heart Association; World HeartFederation; International Atherosclerosis Society; andInternational Association for the Study of Obesity. Circulation120: 1640-1645.doi.org/10.1161/CIRCULATIONAHA.109.192644

American College of Sports Medicine. 2018. ACSM’s Guidelinesfor Exercise Testing and Prescription, 10th ed. Philadelphia:Lippincott Williams & Wilkins.

Chenoweth D, Leutzinger J. 2006. The economic costs of physicalinactivity and excess weight in American adults. Journal ofPhysical Activity and Health 3: 148-163.

Fernandez JR, Redden DT, Pietrobelli A, Allison DB. 2004. Waistcircumference percentiles in nationally representative sampleof African-American, European-American, and Mexican-American children and adolescents. Journal of Pediatrics 145:439-444.

Finkelstein E, Fiebelkorn I, Wang G. 2003. National medicalexpenditures attributable to overweight and obesity: How muchand who’s paying? Health Affairs 3: 219-226.

Jackson AS, Pollock, ML. 1978. Generalized equations forpredicting body density of men. British Journal of Nutrition 40:497-504.

Jackson AS, Pollock, ML, Ward A. 1980. Generalized equationsfor predicting body density of women. Medicine and Science inSports and Exercise 12: 175-182.

Jackson AS, Ross RM. 1992. Understanding Exercise for Healthand Fitness. Houston, TX: CSI Software.

Kavouras SA, Panagiotakos DB, Pitsavous C, Chrysohoou C,Anastasiou CA, Lentzas Y, Stefanadis C. 2007. Physicalactivity, obesity status, and glycemic control: The ATTICAstudy. Medicine & Science in Sports & Exercise 39 (4): 606-611.

Kenney WL, Wilmore JH, Costill DL. 2015. Physiology of Sportand Exercise, 6th ed. Champaign, IL: Human Kinetics.

Morbidity and Mortality Weekly Report (MMWR). 2009.Differences in prevalence of obesity among Black, White, andHispanic adults—United States, 2006-2008. Morbidity andMortality Weekly Report (MMWR) 58: 740-744.

National Institute of Diabetes and Digestive and Kidney Diseases.2017. Overweight and Obesity Statistics.https://www.niddk.nih.gov/health-information/health-statistics/overweight-obesity. Accessed 25 August 2018.

National Center for Health Statistics. 2016. Health, United States,2016: With Chartbook on Long-Term Trends in Health.Hyattsville, MD: National Center for Health Statistics.

U.S. Department of Health and Human Services. 2001. TheSurgeon General’s Call to Action to Prevent and DecreaseOverweight and Obesity. Rockville, MD: U.S. Department ofHealth and Human Services, Public Health Service, Office ofthe Surgeon General.

U.S. Department of Health and Human Services. 2008. PhysicalActivity Guidelines for Americans. Washington, DC: U.S.Department of Health and Human Services.www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services. 2018. PhysicalActivity Guidelines for Americans, 2nd ed. Washington, DC:U.S. Department of Health and Human Services.www.health.gov/paguidelines/second-edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

U.S. Department of Health and Human Services, Centers forDisease Control and Prevention. 2018. Behavioral Risk FactorSurveillance System (BRFSS). www.cdc.gov/brfss. Accessed17 August 2018.

U.S. Department of Health and Human Services, Office ofDisease Prevention and Health Promotion. 2011. HealthyPeople 2020. www.healthypeople.gov/2020. Accessed 12August 2011.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2008. Physical ActivityGuidelines Advisory Committee Report, 2008. Washington, DC:U.S. Department of Health and Human Services.https://health.gov/paguidelines/2008/report/pdf/CommitteeReport.pdf.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2018. 2018 Physical ActivityGuidelines Advisory Committee Scientific Report. Washington,DC: U.S. Department of Health and Human Services.https://health.gov/paguidelines/second-edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

U.S. Department of Health and Human Services, U.S. Departmentof Agriculture. 2015-2020 Dietary Guidelines for Americans, 8thed. Washington, DC: U.S. Government Printing Office.

Wang Y, Beydoun MA, Liang L, Caballero B, Kumanyika SK.2008. Will all Americans become overweight or obese?Estimating the progression and cost of the U.S. obesityepidemic. Obesity 16: 2323-2330.

Wing, RR. 1999. Physical activity in the treatment of theadulthood overweight and obesity: Current evidence andresearch issues. Medicine and Science in Sports and Exercise31 (suppl 11): S547-S552.

World Health Organization. 2018. Obesity and Overweight.www.who.int/news-room/fact-sheets/detail/obesity-and-

overweight. Accessed 17 August 2018.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

2.2.3, 2.3.2, 2.5.1, 6.2.1, 6.2.2, 6.2.3, 6.2.4, 6.4, 6.4.1,6.4.2, 6.4.3, 6.4.4, 6.5.2, 6.53

CHAPTER 7Musculoskeletal and FunctionalHealth

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The prevalence of musculoskeletal disorders and relatedhealth challenges

»  The physical challenges associated with low levels ofmusculoskeletal fitness, as well as common testingmethodologies to assess musculoskeletal fitness

»  How physical activity affects bone, joint, muscle mass, andmuscle function in relationship to musculoskeletal health

»  How physical activity can influence functional and roleability

»  How exercise adaptations positively influence functionalhealth

»  The physical activity guidelines for promoting physicalactivity related to functional health, and the evidencebehind them

OPENING QUESTIONS»  Can exercise improve the strength and quality of bone tissue?»  Why is muscle quantity (muscle mass) and muscle quality

(muscle function) important for good health?

»  How much physical activity is needed for good musculoskeletalhealth?

»  What is functional health? How can functional health beimproved to reduce the risks for physical disabilities?

Have you ever watched a grandparent, aunt, or other older relativestruggle to rise from a sitting to a standing position because of a lackof upper body strength? Have you ever watched (or been) a childwho was not selected for an athletic team or pickup game for lack ofstrength? Do you want to be able to enjoy life, be as independent aspossible, and do all the things you want without physical limitationsinto old age? Each of these questions directly relates to the humanmusculoskeletal system (i.e., bones, muscles, joints, and connectivetissue) and its ability to help us do the physical things we want to do.

Although much of the scientific and popular attention on physicalactivity and health has (appropriately) focused on how exercisehelps the cardiovascular and metabolic systems (see chapter 5), weare learning that the benefits to the musculoskeletal system are justas important. Scientific evidence clearly supports the importance ofmaintaining physical activity as we age to optimize physiological

capacity, minimize physiological limitations, maintain functional androle ability, and reduce the risks of falls (U.S. Department of Healthand Human Services [USDHHS], Physical Activity GuidelinesAdvisory Committee [PAGAC] 2008, 2018). This chapter introducesthese topics and presents the scientific rationale for engaging inphysical activity for musculoskeletal health.

PREVALENCE OF MUSCULOSKELETAL DISORDERS ANDRELATED HEALTH CHALLENGESThe most common musculoskeletal disorders that result from lowphysical activity levels are osteoporosis (bone health),osteoarthritis (joint health), and low levels of the quantity andquality of muscle mass. Osteoporosis (low bone mass andstructural deterioration of bone tissue) is estimated to be a publichealth threat to 44 million Americans, or 55% of those over 50 yearsof age (National Osteoporosis Foundation 2010). Clearly establisheddiagnostic criteria for osteoporosis exist: People with a bone mineraldensity (BMD) below the normal range have the disease. Womenare much more likely than men to have osteoporosis. Of the 10million people estimated to have osteoporosis in the United States in2010, approximately 80% were women and 20% were men.

Why is osteoporosis a problem? Most important, osteoporosis andlow bone mineral density (BMD) contribute to increased bonefracture risk including fractures of the hip, vertebral column, andwrist. The risk of falling is increasingly a problem as we age, and lowBMD can accelerate the risk of fractures that are either spontaneousor secondary to a fall. In 2005, the National Osteoporosis Foundationreported that osteoporosis was related to more than 2 millionfractures in the United States in the following categories:

Hip: 297,000Vertebrae: 547,000Wrist: 397,000Pelvis: 135,000

Other sites: 675,000

Due primarily to the aging of the U.S. population, the incidence ofbone fractures resulting from osteoporosis and low BMD is expectedto increase by a million more cases by 2025, which will contribute tolower quality of life, higher disease management costs, andincreased mortality for those affected. The economic cost ofosteoporosis and low BMD associated with osteoporosis-relatedfractures was $19 billion (USD) in 2005, and has been predicted toaffect 3 million people at a cost of $25 billion by 2025.

Although there are several types of arthritis, osteoarthritis (OA) isthe most common form of joint disease and is associated with jointpain and dysfunction along with irreversible loss of articular cartilage.Osteoarthritis is often thought of as a mechanical joint diseaseaffecting primarily the weight-bearing joints (knees and hips).Clinically, OA symptoms include joint pain, swelling, stiffness, andweakness. The development of OA is associated with increaseddisability and lifestyle challenges.

Approximately 27 million U.S. adults (or ~12% of the U.S.population) are affected by this most common form of arthritis, and itis also the fifth leading cause of disability. To put this intoperspective, California is the only state in the United States(according to the 2010 U.S. Census) with more than 27 millionpeople! Women are affected with OA more than men are, especiallyrelated to the knee. By the year 2030, it has been predicted that 67million people, or 25% of the U.S. population, will suffer from OA.

The economic costs of OA are difficult to estimate because it isoften reported medically as a musculoskeletal condition, and notdifferentiated from other disease processes. Moreover, falls andfractures can occur in the absence of OA. Many of the economiccosts of OA are work related (i.e., absenteeism and presenteeism,terms used in the workplace to define decreased on-the-jobperformance as a result of health problems). In 2007, U.S. costswere estimated at more than $185 billion per year including

physician office visits, hospital and outpatient treatments, medicationuse, diagnostic tests, and other related medical treatments (Kotlarzet al. 2009). Obviously, for those who have OA and requirearthroscopic surgery, joint replacement surgery, or reconstruction,the costs can accumulate rapidly.

RISK FACTORS ASSOCIATED WITH MUSCULOSKELETALDISORDERS AND ASSOCIATED HEALTH CHALLENGESChapter 5 highlighted the major risk factors for cardiovasculardisease (CVD) and diabetes. Although a complete review of all therisk factors associated with low levels of musculoskeletal health andpoor functional health is beyond the scope of this text, we will reviewthe risk factors associated with the musculoskeletal healthchallenges of osteoporosis, osteoarthritis, and low levels of thequantity and quality of muscle mass. As you might have guessedalready, many, but not all, musculoskeletal health challenges areassociated with sedentary lifestyles or low levels of physical activity.

OSTEOPOROSISAccording to the U.S. National Osteoporosis Foundation (2010),there is an extensive list of risk factors associated with thedevelopment of osteoporosis. As with CVD and diabetes mellitus,these factors can be grouped into modifiable and nonmodifiablefactors.Modifiable Risk Factors for Osteoporosis

Physical inactivityTobacco useBeing thin or underweightAlcohol abuseLow sex hormone (estrogen or testosterone) levelsLow calcium or vitamin D intake or absorptionExcessive caffeine intake

Nonmodifiable Risk Factors for Osteoporosis

AgeSexHeredity (genetics)Ethnicity or raceHistory of fractures

Following are descriptions of the modifiable and nonmodifiablerisk factors for osteoporosis:

• Physical inactivity. People who are physically inactive are lesslikely to have optimal bone mineral density (BMD) than their moreactive peers.

• Tobacco use. Smokers reduce their ability to absorb calcium,which is important for good bone health, and smoking also tends tointerfere with estrogen and bone protection.

• Being thin or underweight. Being underweight is associated withsmall bone structure and less weight and force on bones, and maybe associated with poor nutrient intake or eating disorders.

• Age. Advancing age (men >70 years, women >50 years andpostmenopause) is associated with increased osteoporosis riskbecause of physiological changes associated with aging and boneloss.

• Sex. Women are at a higher risk for osteoporosis than men atan earlier age; however, men with lower testosterone or estrogenlevels, or both, are also at increased risk.

• Nutrition. Low calcium and vitamin D intake and availability arerisk factors for osteoporosis. Excessive alcohol and caffeine intakehave also been implicated.

• Heredity (genetics). A family history of osteoporosis canincrease the risk for developing the condition.

• Ethnicity or race. Evidence suggests that some groups havelower rates of osteoporosis than others (e.g., African Americans

have lower rates than American Caucasians, Asians, or Latinos).• Low estrogen or testosterone levels. Normal levels of sex

hormones, by sex, (i.e., estrogen and testosterone) help protectbone; therefore, women who are postmenopausal, women withamenorrhea (i.e., are not menstruating regularly), and some menwith lower testosterone levels may be at higher risk for osteoporosis.

• History of fractures. A history of fractures in adulthood mayindicate that the person already has osteoporosis.

STRENGTH TRAINING AND FRAIL OLDER ADULTSStrength training was once thought to be too dangerous andunproductive for frail older adults. A landmark study byDr. Maria Fiatarone and her colleagues at Tufts University(Fiatarone et al. 1994) was quick to disprove that notion.In this study, 100 nursing home residents who averaged87.3 years of age were randomized to a weight training ora nonexercise control group for a 10-week period. Muscularstrength and muscle mass were measured before and afterthe study. Not only did the training significantly improvemuscular strength in those who did the strength training,but muscle mass increased (2.7%) as well. The outcomeswere much better in the strength training group than inthe group that received dietary supplements alone(nonexercise). This study helped change manypreconceptions about strength training and older adults.

OSTEOARTHRITISOsteoarthritis (OA) is one of many forms of arthritis characterized byexcessive (and lasting) stiffness and swelling in the joints. Unlikeother forms of arthritis, OA is thought to result from abnormalstresses on the joints. According to the U.S. National ArthritisFoundation (2011), the primary risk factors associated with thedevelopment of OA are age, obesity, injury or overuse, genetics or

heredity, and muscle weakness. Not surprisingly, some risk factorsfor OA can be modified, whereas others cannot.Modifiable Risk Factors for OA

Physical inactivityExcessive physical activity, or overuseExcess body mass

Nonmodifiable Risk Factors for OA

AgeSexHeredity (genetics)History of joint injury

Following are descriptions of the modifiable and nonmodifiablerisk factors for osteoarthritis:

• Physical inactivity. Physical inactivity is a two-edged swordwhen it comes to OA. Some physical activity is associated with alower risk of OA, whereas too much provides excessive joint stressand may increase the risk. Physical activity helps increase muscularstrength, which is important for supporting joints (e.g., strongquadriceps for the knee joint).

• Excessive physical activity. Too much physical activity, or ahistory of athletic overtraining (i.e., excessive exercise that producesnegative effects) is associated with an increased risk of OA. Somesports and recreational activities have been found to be associatedwith the development of OA.

• Excess body mass. Overweight (i.e., high BMI) is associatedwith higher rates of OA. This is thought to also be related to jointoverload.

• Age. Joints degenerate over time. This natural degenerationmay be compounded by previous joint injury history, excessivephysical activity or exercise, or both.

• Sex. Women are at a higher risk than men for most types of OA,which is probably due in part to lower levels of quadriceps strengthon average as compared with males, which can influence OAdevelopment in the hips or knees.

• Heredity (genetics). A family history of OA may predispose aperson to developing OA.

• History of joint injury. Previous joint injuries associated withweight-bearing movement (especially at the knee) increase the riskfor developing OA.

• Occupational load. Some occupations require workers to carryheavy loads and this form of overuse may contribute to OA risk.

LOW MUSCLE MASSMusculoskeletal health is not necessarily linked to a specific diseaseprocess. Low muscle mass (also known as sarcopenia) is thought tobe an important determinant of functional health, particularly amongolder adults. Therefore, this section reviews selected factors that areassociated with low levels of functional health, specifically falls,which correlate with low levels of muscle mass quantity and quality.According to the Physical Activity Guidelines Advisory Committee(USDHHS, PAGAC 2008), the three primary risk factors associatedwith low levels of functional health are aerobic capacity, muscularstrength, and balance. Following are the major modifiable andnonmodifiable risk factors for low muscle mass, as well as otherpotential risks.Modifiable Risk Factors for Low Muscle Mass

Physical inactivityTobacco use

Nonmodifiable Risk Factors for Low Muscle Mass

AgeSex

Heredity (genetics)

Following are descriptions of the modifiable and nonmodifiablerisk factors for low muscle mass:

• Physical inactivity. Physical inactivity is associated with lowermuscle mass, particularly in aging, frail people. The “use it or lose it”principle is highly appropriate here.

• Age. Although aging is inevitable, the quantity and quality ofmuscle mass and aerobic capacity in most people can be maintainedat high levels well past the age of 65, if they maintain a normal BMI(18.5 to 25), remain physically active, and do not smoke.

• Sex. Women, on average, have a lower muscle mass than mendo, so it is even more important that they become physically active(in their youth) and remain so throughout their lives.

• Genetics (heredity). Functional health depends on genetics;however, practicing positive behaviors such as being physicallyactive, maintaining a healthy weight, and minimizing risky activitiescan increase the quantity and quality of muscle mass.

KINESIOLOGY AND MUSCULOSKELETAL HEALTHMusculoskeletal function has been repeatedly demonstrated toimprove from engaging in activities such as strength and resistancetraining. Even with moderate-intensity physical activity, most peoplesee improvements in strength (muscle mass quantity) and muscularendurance (muscle mass quality related to function). One does notnecessarily need to lift weights to see musculoskeletal benefits;other activities such as working with resistance bands, doingcalisthenics (push-ups, pull-ups, sit-ups), carrying heavy loads,climbing stairs, and heavy gardening (digging and hoeing) are alsoassociated with positive changes in strength and muscularendurance. Older sedentary adults can see improvements of 50 to100% in certain measures of strength and muscular endurance (e.g.,hand grip and leg extension and flexion) in 8 to 12 weeks.

MUSCULOSKELETAL ADAPTATIONS TO PHYSICALACTIVITY AND EXERCISEPhysiological

Increased muscular strength: Ability to move moreweight

Increased muscular endurance: Ability to sustainmuscular contractions over time

Increased O2max: Increased aerobic capacityIncreased muscle force and power: Increased amount offorce generated by the muscle when contracting,

remaining static, or elongating

Increased muscle fiber size: Skeletal musclehypertrophy can occur with or without measurable gainsin strength.

Improved neural recruitment: Recruitment of morenerves to stimulate muscle contraction

Increases in anaerobic enzymes: Increases in compoundsthat can use fuel without the need for oxygen

Increased anaerobic energy stores: Increased abilityto store fuel when needed for high power output

Improved hormone-mediated bone remodeling: Increasesin bone matrix and mineral turnover

Improved connective tissue function: Improved abilityof tissues to connect, bind, support, and anchor the

body

No change, or increase, in BMD: No change or increasein bone quality

Maintenance of, or increase in, lean muscle mass:

Increase in total muscle

Maintenance or loss of weight: Weight loss even withan increase in muscle tissue

Biomechanical

Improved economy: Ability to move more efficientlyImproved balance: Maintenance of even weightdistribution to prevent falling

Improved mobility: Increased range of motion ofmuscles and connective tissue around joints

Increased motor skill function: Improved communicationbetween the brain and muscles for smoother, more

efficient operation

Improved proprioception: Improved ability of the bodyto sense movement and space; helps in movement and

balance

Behavioral

Increased self-esteem and self-confidence: Improvedsatisfaction with or confidence in oneself,

particularly related to physical activity and

exercise

Improved self-efficacy: Improved attitudes, abilities,and cognitive skills, particularly related to

physical activity and exercise

Decreased depression and anxiety: Less moodiness,despondency, nervousness, unease, and worry

The highlight box Musculoskeletal Adaptations to Physical Activityand Exercise contains some of the long-term exercise-relatedadaptations acquired by engaging in muscle-strengthening activities,which can positively influence musculoskeletal health. The amount ofphysiological adaptation related to each of the benefits is dosedependent, meaning that low doses yield lower results and fewerchanges than do higher doses. Chapter 2 discusses physical trainingprinciples in more detail.

Although cardiorespiratory adaptations (see chapter 5) tomusculoskeletal strengthening activities are less than those seenwith aerobic (cardiorespiratory) physical activities, sedentary peoplecan increase their O2max (or O2peak) from 5 to 8% withresistance training. Those who engage in circuit training, a form ofinterval training using resistance training and aerobic exercise (seechapter 2 for more), often increase their O2max (or O2peak) byapproximately 5% (Gettman and Pollock 1981).

Increases in the rate of force (strength) development and power(time rate of work) are observed over time during physical activityand resistance training. Musculoskeletal strengthening results in theability to recruit more motor units (the nerve and the fibers itcontrols), increased individual muscle fiber size (fast and slowtwitch), increased numbers of anaerobic enzymes, and higheramounts of anaerobic energy stores. All of these factors areimportant for performing high-intensity, short-durationmusculoskeletal activity.

Connective tissue changes associated with the specific musclesused during musculoskeletal strengthening activities may includeincreases in ligament strength, tendon strength, and collagencontent. Resistance training can also cause positive hormonalchanges (e.g., up-regulation of anabolic hormone receptors) thatallow for the remodeling of bone. Further, resistance activities canincrease bone mass (or BMD) in some people, or may at least delaybone mass loss in people at risk for osteoporosis.

Exercise physiology research has clearly shown that regularparticipation in physical activity and musculoskeletal strengtheningincreases lean muscle mass (quantity and quality) and reduces bodyfat, thereby helping with weight management. Figures 7.1 through7.3 illustrate common changes in musculoskeletal fitness or functionafter physical activity or exercise training.

Figure 7.1   Motor units (i.e., the nerve plus the muscle fibers it controls)that include slow-twitch fibers (aerobic) and fast-twitch fibers (anaerobic)and the relationship between force production and motor unit recruitment.Physical activity and exercise improve the ability to increase therecruitment of motor units and therefore improve force production.Reprinted by permission from D. French, “Adaptations to Anaerobic Training Programs,” inEssentials of Strength Training and Conditioning, 4th ed., edited for the National Strengthand Conditioning Association by G.G. Haff and N.T. Triplett (Champaign, IL: HumanKinetics, 2016), 91.

Biomechanically, improved economy or efficiency (i.e., reducedenergy cost at a given workload) can be expected aftermusculoskeletal strengthening. For elderly people, this may meansimple yet important improvements in day-to-day activities. Balanceand stability are often improved by engaging in resistance trainingactivities. Improved mobility (flexibility and range of motion) andmotor skills obtained through strengthening activities can give peoplethe confidence to engage in future physical activity and exerciseactivities. Their peripheral proprioception (i.e., sense of position andmovement) response often improves as well.

Figure 7.2   Bone remodeling, progressing from left to right, in response tomechanical loading such as that from participating in regular physicalactivity and exercise.

Behaviorally, people often feel better and have more self-confidence after several weeks of participation in physical activitythat includes resistance activities. Some evidence suggests thatpeople who participate in muscle-strengthening and resistancetraining activities experience lower levels of depression and anxiety,and they also probably experience higher self-efficacy (i.e., a senseof personal accomplishment and well-being) levels.

COMMON TESTS OF MUSCULOSKELETAL FITNESS ORFUNCTIONMany tests have been developed over the years to evaluatemusculoskeletal fitness and function. Some are fairly easy to use,whereas others require a laboratory and medical personnel. Fieldtests, which can be done fairly easily and with large numbers ofpeople, may not be as accurate as clinical ones. A familiarity withsome of the common tests of musculoskeletal fitness or function(and the interpretation of their results) will help with the following:

Establishing baseline levels of strength and muscular enduranceUnderstanding the strengths and weaknesses of the scientificliterature in this areaDetermining the extent of disabilities or limitations that caninfluence the ability to engage in physical activity and exerciseDeveloping a plan for including regular musculoskeletalstrengthening activities in an overall physical activity programUnderstanding the need to seek musculoskeletal rehabilitationor medical advice

Figure 7.3   Relative responses of physiological variables to training anddetraining (see chapter 2).Reprinted by permission from S.J. Fleck and W.J. Kraemer, Designing Resistance TrainingPrograms, 4th ed. (Champaign, IL: Human Kinetics, 2014), 298.

The websites listed in the web resource and the references at theend of this chapter provide more comprehensive information onmusculoskeletal fitness and function tests, and how to successfully

administer and interpret them. This section provides a brief overviewof the most common muscle and bone assessments.

A list of assessments for strength, muscular endurance, power,balance, gait, mobility, and bone strength can be found in thehighlight box Assessments of Musculoskeletal Fitness or Function.The discussion that follows briefly describes the assessments andhow they might be used clinically. Several commercial websites offerfree performance evaluation calculators (see the e-Media section atthe end of this chapter).

Muscular strength is essentially the ability of a muscle or set ofmuscles to generate adequate force to move a predeterminedweight. People with weightlifting experience often perform muscularstrength testing with free weights or machine weights. The verycommon 1-repetition maximum (1RM) test indicates how much aperson can lift one time; 1RM can be determined for several musclegroups (e.g., arms, legs, chest) and is a useful indicator of overallmuscular strength. The 1RM value is easy to use when developing amuscle-strengthening plan. People without weightlifting experienceor who have safety issues can perform other lifts such as a 5RM or a10RM, and their 1RM can be estimated from their performance onthese lifts (see Baechle and Earle 2008).

Handgrip dynamometry is a simple static method of assessinggrip strength using commercially available devices; it is correlated toother measures of static strength. Isokinetic dynamometry is a test ofdynamic strength in which the subject performs an exercise througha range of motion at a constant speed. Because isokinetic testingrequires expensive equipment, it is most often performed in clinicaland rehabilitation settings. Photos of some common tests ofmusculoskeletal fitness or function are shown in figure 7.4.

Contrary to muscular strength, muscular endurance refers to theability of a muscle or set of muscles to repeatedly generate asubmaximal force (perform repeated contractions) or to sustain acontraction for a period of time. Muscular endurance testing can alsobe performed using free weights or machine weights (once 1RM has

been established) by lifting a weight that is a percentage of 1RM(e.g., 70%) as many times as possible. The percentage of 1RM usedto determine muscular endurance varies based on the person beingtested.

ASSESSMENTS OF MUSCULOSKELETAL FITNESS ORFUNCTION

Strength: 1RM, 5RM, 10RM, handgrip dynamometry,

isokinetic dynamometry

Muscular endurance: Number of lifts using 70% of 1RM,

push-ups, pull-ups, sit-ups, sit-to-stand tests,

sport-specific tests

Power: Wingate anaerobic power test, standing long

jump, vertical jump

Balance: One-leg stand, gait speed, Berg balance

scale

Gait: Get-up-and-go, curve course walk

Mobility: Goniometer test

Bone strength: DXA, ultrasound

Simple and common weight-bearing muscular endurance testssuch as push-up, pull-up, and sit-up (or curl-up) tests are traditionalassessments of muscular endurance, and specific protocols exist fortesting various populations. Sit-to-stand tests (e.g., the number ofrepetitions someone can complete in 30 seconds) for evaluating themuscular endurance of the elderly can be found in the research andclinical literature. Sport-specific tests for higher-fit people that assessmuscular endurance are also readily available (see the websiteslisted in the e-Media section).

Figure 7.4   Musculoskeletal fitness and function may be assessed in manyways, including (a) handgrip dynamometry, (b) 1RM, and (c) the vertical jump.

Measuring power in younger people is usually easier than in olderpeople because of the need for explosive effort (>95%). The Wingateanaerobic power test can be used in laboratory settings to determinemaximal and average muscular power. Traditional power tests suchas the standing long jump and vertical jump can provide simplemeasures of power that are easily interpreted.

Balance assessments are primarily for older people who may beat higher risk for falls (i.e., have low functional health), people whoare in physical rehabilitation programs (e.g., physical therapy), andathletes who are striving for high levels of performance (e.g.,dancers, gymnasts, martial artists). The one-leg stand is a balancetest that can be performed with the eyes open or closed; the time theperson can stand in the proper position is recorded. Gait speed on astraight or curved course can be used to determine the balanceabilities of elderly people. The Berg balance scale is a functional testthat provides a composite balance score of 14 items for evaluation ofthe elderly.

Gait assessments are also used primarily for older people toevaluate their functional health. Common tests related to gaitanalysis are the get-up-and-go assessment and various curvedwalking course assessments.

Numerous mobility (flexibility and range of motion) tests havebeen developed to evaluate people of all ages. Perhaps the mostcommon assessment of mobility is goniometry, which involves

having a professional (e.g., a physical therapist or exercisephysiologist) measure joint angles, movement limitations, or both.

The only sure way to assess bone mineral content is to surgicallyremove a piece of bone (by making an incision or inserting a needleinto a bone close to the skin’s surface) and analyzing it in alaboratory. This is obviously a painful procedure; it is most frequentlydone to diagnose bone diseases such as cancer. Technologicaladvancements have resulted in the development of BMD screeningtools that are quite accurate, painless, and fairly low cost. Bonestrength screening and assessment are common clinical andmedical assessments and best accomplished with the use of dual-energy X-ray absorptiometry (DXA). DXA is the most valid andreliable screening measure for BMD. Other techniques such asultrasound (i.e., sound waves) are available, but currently are lessaccurate than DXA.

Figure 7.5 illustrates the relationship between BMD and aging, aswell as a strategy (i.e., increased physical activity includingmusculoskeletal activities) to prevent or delay osteoporosis byincreasing peak bone mass in youth. The figure shows normal BMDloss with aging in a healthy, inactive individual and the increases andmaintenance of higher levels of BMD for a healthy, physically activeindividual with aging. Peak bone mass (or BMD) occurs on averagefor men and women by age 30 and begins to drop after menopausein women, and by age 70 in most men. Teenage girls, as apopulation, are an excellent target group to encourage regularparticipation in musculoskeletal (as well as other physical activityand exercise) activities throughout life, because they should be ableto increase their peak bone mass. This, at least theoretically, mightdelay the point at which they would develop osteoporosis orexperience negative musculoskeletal symptoms or disabilities.

Figure 7.5   Schematic illustration of a strategy to prevent or delay theonset of osteoporosis by increasing peak bone mass during youth.Reprinted by permission from C.J.R. Blimkie and O. Bar-Or, New Horizons in PediatricExercise Science (Champaign, IL: Human Kinetics, 1995), 78.

PHYSICAL ACTIVITY AND MUSCULOSKELETAL HEALTHAlthough extensive research documents the benefits of resistancetraining, particularly for athletic competition, only since the early1980s has this evidence been developed enough to make specificrecommendations for engaging in musculoskeletal activities.Historically, it was thought that the only purpose of the skeletalsystem was to provide structure for muscles; its role in physicalactivity and exercise was considered minimal. We obviously nowknow that the skeletal system is a living organ that can changesubstantially based on external stimuli, such as physical activity.Similarly, the connective tissues of muscles, tendons, and ligaments,as well as weight-bearing bones, have been found to become thickerand develop greater tensile strength in response to dynamic exercisetraining. In addition, bones’ response to resistance exercise has

been to become thicker and stronger regardless of their weight-bearing function. That is, the benefits are not all due to the constantbearing of body weight: Bone health can be improved throughphysical activity.

SCIENTIFIC EVIDENCEThere is moderate scientific evidence of an inverse relationshipbetween physical activity and exercise and the risk of hip fractures inadults (USDHHS, PAGAC 2008). The evidence of a relationshipbetween physical activity and the risk of vertebral fractures exists,but it is not as strong as that for hip fractures. There is no directevidence that regular moderate-intensity physical activity promotesthe development of OA. Participation in low or moderate levels ofphysical activity may protect against the development of OA,whereas participation in moderate-intensity, low-impact physicalactivity has been shown to decrease pain and increase function,quality of life, and mental health in people with OA, rheumatoidarthritis, and fibromyalgia (i.e., overall muscular pain and aching).The current evidence that physical activity delays the onset ofdisability from OA is weak.

Much of what we know about the effects of physical activity andexercise on bone health includes information not on activity but oninactivity. Studies have looked at BMD and bone mineral content(BMC) in astronauts who have spent multiple weeks or months inspace with zero gravity and thus no force on their skeletal systems.These studies consistently show that people subjected to theseenvironments (1) show measurable bone loss that is not uniformlydistributed across the skeleton, (2) absorb vitamin D and calcium(two micronutrients important for bone strength) less efficiently, and(3) need much more time to rebuild the lost bone than it took to loseit. Other studies have specifically looked at the effects of severaldays or weeks of complete bed rest on physiological factors like O2max. In the study results shown in figure 7.6, fitter (trained)individuals actually had greater decrements with inactivity (20 days

of bed rest) than less fit (sedentary) individuals, and the fitterindividuals required 55 days to regain their baseline fitness levels.Clearly, these conditions can accelerate the risk of osteoporosis,osteoporotic fractures, or both.

Figure 7.6   The effects of 20 days of bed rest and 55 days of retraining onO2max for five individuals.

Adapted by permission from B. Saltin, “Response to Submaximal and Maximal ExerciseAfter Bed Rest and Training,” Circulation 38, no. 7 (1968): 75.

Although the scientific evidence is never as strong as we want itto be, existing studies show fairly consistently that participation inregular physical activity and exercise can reduce the risk of hipfractures anywhere from 36 to 68%, and regular physical activity canincrease BMD consistently by 1 to 2%. These data are based onshort-term exercise training studies, most of which have been lessthan one year in duration. For this reason, the exact benefits of alifetime of physical activity participation are unknown. Further,benefits of physical activity on BMD have been found forpremenopausal women, menopausal women, and adult men.

What about physical activity for people who already have OA?Does it help? There is fairly strong evidence that people of any agewith preexisting OA seem to benefit from aerobic and resistanceexercise. Muscular strength improves, as does BMD. Women withOA may benefit more than men from resistance training becausethey likely have lower baseline strength levels. General muscular

strength benefits of physical activity are similar for men and womenacross the life span, although they diminish with older age.Information on the benefits of physical activity on the bone andgeneral muscular health of people of various races or ethnicities islacking.

How much physical activity is necessary? The effective dose ofphysical activity and exercise for musculoskeletal health variesdepending on the desired outcome (bone, joint, or muscle health).For bone health (depending on the study), four hours of walking perweek, 2 to 4 hours of moderate- or vigorous-intensity physicalactivity each week, and one hour of weekly physical activity haveeach been associated with a 36 to 41% reduction in the risk of hipfracture. Weight-bearing endurance and resistance physical activityof moderate intensity three to five days per week for 30 to 60minutes per session increases BMD. Walking-only protocols mayimprove spinal BMD (moderate evidence of bone changes).

Evidence strongly suggests an association between physicalactivity and relief from pain in people with arthritis. The suggesteddose of physical activity and exercise for adults with arthritis (toreduce pain and disability and increase function) is 130 to 150minutes per week of moderate-intensity, low-impact activity; expertssuggest 30 to 60 minutes per session, three to five days per week.Both aerobic and muscle-strengthening activities improve jointfunction and reduce pain. Progressive, high-intensity (60 to 80% of1RM) muscle-strengthening activities can preserve or increaseskeletal muscle mass, power, and intrinsic neuromuscular activation.

The effects of an accumulation of physical activity and exercisethroughout the day on musculoskeletal health have not been tested,or research is limited. The scientific evidence from randomizedcontrolled trials and laboratory animal studies has shown theintensity of loading forces to be the key determinant for skeletalresponse. Joint injuries and carrying excess body mass are moreimportant risk factors for OA than sport participation. Finally,endurance types of physical activity do not increase muscle mass,

but they may slow the rate of muscle mass loss with aging, whilepreserving function.

GUIDELINESResistance training and the options available related to muscle-strengthening activities were discussed earlier in the chapter. Thissection contains the Physical Activity Guidelines for Americansrecommendations in lay terms. The guidelines for musculoskeletalhealth have been divided into three parts: children and adolescents(ages 6 to 17), adults (ages 18 to 64), and older adults (>65 years).

Like aerobic activities (see chapter 2), muscle-strengtheningactivities should be based on the dose-response concept—or in thiscase, intensity, frequency, and repetitions. Following are definitionsrelated to resistance training:

Intensity: How much weight or force is lifted or used relative tohow much a person is able to lift or exertFrequency: How often (expressed usually per week) a persondoes muscle-strengthening activitiesRepetitions: How many times a person lifts a weight in a givenset and how many sets the person performs (related to restbetween reps and sets, or groups of repetitions)

The benefits of muscle-strengthening activities are limited to themuscle groups that are worked. Therefore, people need to work themajor muscle groups, which include the legs, hips, back, abdomen,chest, shoulders, and arms.

Bone-strengthening activities can include both aerobic andmuscle-strengthening activities, because both promote growth andstrength, particularly compared to sedentary living. Bone-strengthening activities include jumping jacks, running, brisk walking,and weightlifting. Any weight-bearing activity can count as a bone-strengthening activity—even stair climbing.

Children and adolescents should participate in muscle-strengthening activities at least three days per week, as part of the

overall recommendation of 60 minutes or more of physical activityand exercise per day. They should also participate in bone-strengthening activities at least three days per week, as part of thesame overall recommendation. Table 7.1 contains specific examplesof muscle-strengthening and bone-strengthening activities forchildren and adolescents, as well as for adults and older adults. Asshown, children and adolescents do not need to engage in formalresistance training to acquire musculoskeletal benefits. Adults andolder adults should engage in muscle-strengthening activitiesinvolving all major muscle groups at moderately to vigorously intenselevels at least twice per week to see improvements in muscularstrength and endurance.

No specific number of repetitions has been recommended forresistance training, but people should perform to the point at whichperforming another repetition without help would be difficult.Resistance training involving one set of 8 to 12 repetitions usingseveral muscle groups has increased strength, although performingtwo or three sets, with the appropriate amount of rest between sets,may be more effective. Muscular strength and endurance changesoccur progressively over time, and increases in the amount ofweight, frequency, or both, can result in greater changes.

Adults and older adults may benefit from engaging in warm-up(prior to physical activity bout) and cool-down (after physical activitybout) activities that include muscle-strengthening activities. Theseactivities slowly increase the blood flow to the working muscles,thereby helping to deliver fuel and take away metabolic waste.Adults and older adults may also benefit from performing flexibilityactivities (e.g., stretching), although no scientific evidencedocuments health benefits related to stretching, and stretching doesnot seem to reduce the risk of injury associated with physical activity.

Table 7.1   Examples of Muscle- and Bone-Strengthening Activitiesby Age Group

Population

Type of activity

Muscle strengthening Bone strengthening

Children Games such as tug-of-warModified push-ups (with knees onthe floor)Resistance exercises using bodyweight or resistance bandsRope or tree climbingSit-ups (curl-ups or crunches)Swinging on playground equipment orbars

Games such as hopscotchHopping, skipping, jumpingJumping ropeRunningSports such as gymnastics,basketball, volleyball,tennis

Adolescents Games such as tug-of-warPush-ups and pull-upsResistance exercises with exercisebands, weight machines, handheldweightsClimbing wallSit-ups (curl-ups or crunches)

Hopping, skipping, jumpingJumping ropeRunningSports such as gymnastics,basketball, volleyball,tennis

Adults andolderadults

Exercises using exercise bands, weight machines, handheldweightsCalisthenic exercises (body weight provides resistance tomovement)Digging, lifting, and carrying as part of gardeningCarrying groceriesSome yoga exercisesSome tai chi exercises

Reprinted from USDHHS, PAGA (2008).

In 2018, the Physical Activity Guidelines Advisory Committeeconcluded that there was strong scientific evidence that participationin community-based or home-based physical activity programs cansignificantly reduce the risk of injury from falls. These types ofinjuries can include bone fractures, head trauma, and soft-tissueinjury. Older adults who are at risk for falls should include balanceactivities such as backward walking, sideways walking, heel walking,toe walking, and standing from a sitting position in their physicalactivity and exercise plans at least three times per week. Combiningbalance and muscle-strengthening activities for 90 minutes perweek, along with moderate-intensity walking for 60 minutes perweek, can maintain functional health and may reduce the incidenceof falls. Emerging evidence indicates that higher-velocity resistance

movements at lower intensities may improve power in the elderlymore than lifting at higher intensities and lower velocities.

The specific combinations of type, amount, and frequency ofactivities that might reduce falls are, unfortunately, unknown.However, some evidence shows that tai chi exercises may helpprevent falls. Older adults can start balance and muscle-strengthening activities by holding on to stable supports (e.g.,furniture) and wean themselves away from the supports over time.

FUNCTIONAL HEALTHMusculoskeletal health is not necessarily linked to a specific disease,but low levels of musculoskeletal health (low muscle mass and poormuscle function) can contribute to poor functional health, functionalability, and role ability. Functional health (sometimes called health-related quality of life) is a concept that suggests that an otherwisehealthy person may live with some type of functional disability(USDHHS, PAGAC 2008, 2018) and includes two key subitems:functional ability and role ability. In a practical sense, functionalhealth includes being able to physically do the things one wants todo without pain or limitation. The concept of functional health bridgesthe gulf between the performance-related orientation of physicalactivity and the health-related orientation of public health. It is thekey reason physical activity is important.

At what age do many older people you know lose their functionalhealth? Do you think regular physical activity helps maintainfunctional health longer? Why or why not?

Functional ability refers to the capacity to perform a task,activity, or behavior independently. For example, an elderly womanwho is unable to go grocery shopping, lift and store her groceries athome (e.g., a heavy milk jug), or successfully move around a two-story house because of musculoskeletal limitations has a loss offunctional ability. Role ability, on the other hand, refers to the abilityto perform activities of daily living (ADLs) and instrumentalactivities of daily living (IADLs) (USDHHS, PAGAC 2008).

Examples include being able to play with her grandchildren orperform self-care tasks such as bathing and laundry. The loss offunctional ability and role ability would obviously impair functionalhealth, although factors other than physical changes (e.g., themental health challenges of aging) could also negatively affectfunctional health.

The prevalence of poor functional health is difficult to determine inany population because it is multifactorial and a variety of definitionsexist. However, it has been reported that the economic cost of fallinjuries of those over 65 in the United States, which are often due topoor functional health, exceeded $19 billion in 2000. As the elderlypopulation continues to grow, it is expected that the costs will reach$54.9 billion by the year 2020.

Figure 7.7 illustrates a model that links the relationships amonglifestyle behaviors, health status, exercise science principles, andoutcomes such as functional health and peak performance. Basicfunctional health should be a primary goal for everyone; beyond that,further participation in physical activity and exercise may lead tohigher levels of performance. An understanding of basic exercisescience principles is necessary for understanding how to maintainfunctional fitness, how to exercise, and how to face the challenges ofmaintaining physical activity and exercise (at least for healthbenefits), such as mobility challenges, medical management issues,and exercise rehabilitation challenges. For example, managingdisease processes (e.g., type 2 diabetes) or maximizing the benefitsof rehabilitation (after athletic injury or relapse) requires that peoplefirst maintain or regain their basic functional health; only then canthey optimize performance. A primary message to share regardingdeveloping and maintaining functional health and optimizingperformance is that research has clearly demonstrated theimportance of avoiding inactivity for maintaining and improvingfunctional health (USDHHS, PAGAC 2008).

RISK FACTORS FOR POOR FUNCTIONAL HEALTH

Many of the risk factors for poor functional health overlap with thosefor osteoporosis, osteoarthritis, and low muscle mass as discussedearlier. This is because poor functional health is often a key by-product of these (and other) chronic conditions. Functional health isnot necessarily linked to a specific disease process; however, beingphysically inactive for long periods of time reduces functional health.The basic risk factor for poor functional health is physical inactivity;existing or developing mobility challenges, medical managementissues, and rehabilitation challenges further add to the risk.

Figure 7.7   Relationships among lifestyle behaviors, health status, exercisescience principles, and outcomes such as functional health and peakperformance.

Low levels of functional health, which can lead to falls and otherdisabling conditions, correlate highly with low levels of muscle massquantity and quality. According to PAGAC (USDHHS, PAGAC 2008),the three primary risk factors associated with low levels of functionalhealth are low aerobic capacity, a lack of muscular strength, andpoor balance. In addition, cultural and social factors can affectfunctional health, including lack of social support (the absence of ahuman support network or assistance).

ASSESSMENTS OF FUNCTIONAL HEALTH STATUSSF-36 (long) and SF-12 (short)Measures multiple subdomains of functional health statusincluding physical and role function. Originated in theMedical Outcomes Study (SF-36.org 2011).

Functional Independence Measure (FIM)Measures physical and cognitive disability (Center forOutcome Measurement in Brain Injury 2011a).

Functional Assessment Measure (FAM)Meant to supplement FIM by integrating additional conceptssuch as community integration, orientation, and emotionalstatus (Center for Outcome Measurement in Brain Injury2011b).

Quality of Well-Being Scale (QWB)One of the earliest functional health status tools;measures comprehensive quality of life and focuses to alarge extent on disease symptoms (University of Californiaat San Diego Health Services Research Center 2011).

COMMON TESTS OF FUNCTIONAL HEALTHThe tests highlighted earlier in the chapter for osteoporosis,osteoarthritis, and muscle mass focus largely on physiologicalparameters. Functional health status is a complex concept thatencompasses quality of life issues such as role functioning, physicalfunctioning, social functioning, and emotional status. Because these

issues go beyond physiological concepts (although they are verymuch related to them), they are best measured using tests that focuson self-assessment or the assessment of a third party (e.g., aphysician or researcher). These tests do not isolate one aspect offunctional health (e.g., a muscle or joint), but rather, attempt tointegrate observations into broad indexes of function. The highlightbox Assessments of Functional Health Status lists some of the morecommon measures used to assess functional health status.

FITNESS RECOMMENDATIONS FOR FUNCTIONAL HEALTHFigure 7.8 shows the results from several research studiesconcerning the relationship between the amount of physical activityor exercise performed regularly and mobility limitations. Theindividuals who were in the lowest physical activity or exercisecategory were also those who needed medical evaluation due totheir mobility limitations. Figure 7.9 also shows that more activepeople were at lower odds ratios, or less risk, for functional healthproblems as measured by various functional health, ADL, or IADLoutcomes.

Figures 7.8 and 7.9 show clearly that higher levels of participationin physical activity and exercise are significantly associated withmeasures of better functional health. The diversity of methods usedin the many research studies summarized does not allow us tospeculate on a specific dose-response relationship between theamount of physical activity or exercise and functional health.However, the findings in figures 7.8 and 7.9 do illustrate that modestlevels of physical activity and exercise are associated with lower riskfor functional and role limitations.

SCIENTIFIC EVIDENCEThere is moderate scientific evidence that physical activity andexercise, at midlife and beyond, reduce the risk of moderate tosevere functional limitations (USDHHS, PAGAC 2008). There is alsoevidence that regular physical activity or exercise is safe and

improves functional ability. There is not currently enough evidence toshow that physical activity or exercise improves or maintains roleability or prevents disability in older adults who already havefunctional limitations. Strong evidence suggests that regular physicalactivity or exercise is safe and reduces the risk of falls in older adultsby 30%.

Figure 7.8   The relationship between increased physical activity levels andthe risk of mobility limitations.Adapted from USDHHS, PAGAC (2008, G-6).

Figure 7.9   The relationship between increased physical activity levels andthe risk of functional health problems as shown from several studies.Adapted from USDHHS, PAGAC (2008, G-6).

Participation in regular physical activity and exercise can preventor delay function or role limitations (or both) by 30% (moderate tostrong evidence). Risk reduction appears to be similar for men andwomen; evidence regarding relationships between physical activityand exercise and functional health for racial and ethnic groups islimited.

Moderate evidence suggests a dose-response relationshipbetween physical activity and exercise and the prevention or delay offunction and role limitations. The dose-response relationshipbetween physical activity and exercise and the prevention of falls inolder adults has not been tested. The dose of physical activity orexercise needed for prevention of falls is not known, but participationin walking activities can improve functional health. The maintenanceor improvement of functional health requires at least 30 minutes ofmoderate- or vigorous-intensity physical activity three to five daysper week, emphasizing aerobic and muscle-strengthening activities(strong to moderate evidence).

To lower the risk of falls, exercise programs should includebalance training and muscle-strengthening activities three times perweek for 30 minutes each session (strong evidence); addingmoderate-intensity walking activities two or more other times perweek is also recommended. Some evidence suggests thatparticipation in tai chi one to three or more times per week mayprevent falls.

The evidence for the effects of the accumulation bouts of physicalactivity and exercise throughout the day on functional health is notcurrently available. It is important to remember that most midlife andolder adults have very low fitness levels. For this reason, anyprogram of physical activity or exercise focused on improving ormaintaining functional health should include slow progressions in thevolume of activities to reduce the risk of adverse events.

GUIDELINESPeople who have lost some ability to perform a task of everyday life,such as climbing stairs, have a functional limitation. In older adultswith existing functional limitations, scientific evidence indicates thatregular physical activity is safe and improves functional ability. ThePhysical Activity Guidelines for Americans offer the followingguidelines for achieving or maintaining functional health in adultswith disabilities (USDHHS 2008):

Aerobic activity is recommended to be done throughout theweek in sessions lasting at least 10 minutes, at one of thefollowing levels and durations:

Moderate-intensity aerobic exercise totaling 150 minutes perweekVigorous-intensity aerobic exercise totaling 75 minutes perweekA combination of the preceding

Muscle-strengthening activity for all major muscle groups isrecommended at moderate or high intensity on two or more

days per week.

Adults with a disability who are not able to meet theserecommendations should be encouraged to avoid inactivity byperforming as much physical activity as they are able. They shoulddiscuss with their health care provider the type and duration ofphysical activity that is appropriate for their ability.

Adults with chronic conditions should engage in regular physicalactivity because doing so can improve their quality of life and reducethe risk of developing new conditions. The type and amount ofphysical activity should be determined by their abilities and theseverity of the chronic condition. The Physical Activity Guidelines forAmericans emphasize the following three messages for people withchronic medical conditions (USDHHS 2008):

Regular physical activity can confer important health benefits.Physical activity is safe if done according to abilities.People with chronic conditions should always consult with theirhealth providers about which types of physical activity areappropriate.

For many chronic conditions, physical activity provides therapeuticbenefits and is part of the recommended treatment for the condition.The Physical Activity Guidelines for Americans do not specificallyaddress therapeutic exercise or rehabilitation.

LEADER PROFILESandra M. Mahecha, MD, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?When I finished my medical training in Colombia, I wasinterested in what we knew then as the field of sportsmedicine. At the time there was no formal sports medicinespecialty in Columbia, so I went to Brazil for thecoursework and to simultaneously perform an internship ina research center—Centro de Estudos do Laboratório deAptidão Física de São Caetano do Sul (CELAFISCS), where Iwould research physical activity, exercise, andperformance. In 1994, the secretary of health in the stateof São Paulo requested a community physical activityprogram as a form of health promotion, so this is how myinterest and study began in the area. For 24 years I wasdirectly involved with the Agita São Paulo Program and thephysical activity networks, Red de Actividad Física de lasAméricas (RAFA) and Agita Mundo. After leaving Brazil, Ifollowed my dream to promote physical activity in Chile,where I currently run a physical activity promotionprogram in the most famous sports medicine clinic in thecountry, Clínica MEDS, and launched the new specialty ofsports medicine and physical activity with the UniversidadMayor and Clínica MEDS. This has been a way to continuedeveloping projects to improve the health of thepopulation through the regular practice of physicalactivity.

Did any one person have a major influence on your career?How?Without a doubt my academic, professional, and personaltraining was accomplished thanks to the support ofCELAFISCS members and the leadership of Victor Matsudo,

who knew how to lead and encourage us for this purpose inBrazil and Latin America. With his vision I was able tolearn to research with limited resources and to transformtheory into practice. In the same way, Dr. FernandoGonzález Foretic in Chile was a key person who createdopportunities, contacts, alliances, and systems ofdelivering physical activity to different sectors ofsociety.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?My primary interests are to promote physical activity invulnerable populations such as adults, frail people, andinstitutionalized older adults; I continue to be committedto implementing the SENIOR FIT program that we developedas an exercise program for active and healthy aging. Inaddition, I hope to see professionals trained in healthand exercise, not only with doctors in the specialty, butalso in clinical physiology of exercise and prescriptionof exercise programs for older adults. In addition to thisI have a strong commitment to the theory “exercise ismedicine,” and to make physical activity a part of thetraining and focus for all doctors and healthprofessionals in Chile and Latin America.

Why do you do what you do?Because it’s my dream, and it’s what I love doing. Iconsider it a small contribution to make people livebetter and happier!

What are two key issues that must be addressed by 2030?The recommendation that physical activity be included as aformal part of health care (private and public) everywherein the world, and that physical activity be encouraged inpeople with rare or little-known chronic diseases.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

The prevalence of common musculoskeletal challenges suchas osteoporosis (bone health), osteoarthritis (joint health),and low levels of the quantity and quality of muscle mass arehigh in the U.S. population.Osteoporosis (i.e., low bone mass and structural deteriorationof bone tissue) is estimated to be a public health threat to 44million Americans, or 55% of those over 50 years of age.Osteoarthritis (OA) is the most common form of joint diseaseand is associated with joint pain and dysfunction along withan irreversible loss of articular cartilage.Functional health is a concept that suggests that anotherwise healthy person may have some form of functionaldisability and includes the maintenance of functional abilityand role ability. Functional ability refers to the capacity toperform a task, activity, or behavior independently. Roleability refers to the ability to perform activities of daily living(ADLs) and instrumental activities of daily living (IADLs).Common risk factors for most musculoskeletal disorders arephysical inactivity, overweight, sex, heredity, and age.The physiological, biomechanical, and psychological benefitsof participating in physical activity and exercise onmusculoskeletal health are numerous.Common musculoskeletal tests can be used to determinelevels of strength, muscular endurance, power, balance, gait,and mobility.Youth should engage in muscle-strengthening activities thatinclude the major muscle groups at least three days perweek, and adults should participate at least two days perweek.Common risk factors for low levels of functional health arephysical inactivity, low physical fitness, tobacco use, age, sex,and heredity or genetics.

Simple tests of functional health address muscular strength,muscular endurance, balance, gait, and mobility.Moderate levels of physical activity or exercise areassociated with lower risk for functional and role limitations.Participation in regular physical activity and exercise canprevent or delay function and role limitations and reduce therisk of falls in older adults by 30%.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYBaechle TR, Earle RW, eds. National Strength and Conditioning

Association. 2008. Essentials of Strength Training andConditioning, 3rd ed. Champaign, IL: Human Kinetics.

Center for Outcome Measurement in Brain Injury. 2011a.Introduction to the FIM. www.tbims.org/combi/FIM. Accessed11 January 2019.

Center for Outcome Measurement in Brain Injury. 2011b.Introduction to the Functional Assessment Measure.www.tbims.org/combi/FAM. Accessed 11 January 2019.

Fiatarone MA, O’Neill EF, Ryan ND, et al. 1994. Exercise trainingand nutritional supplementation for physical frailty in veryelderly people. New England Journal of Medicine 330: 1769-1775.

Gettman LR, Pollock ML. 1981. Circuit training: A critical review ofits physiological benefits. Physician and Sportsmedicine 9: 44-

60.Kotlarz H, Gunnarsson CL, Fang H, Rizzo JA. 2009. Insurer and

out-of-pocket costs of osteoarthritis in the U.S. Arthritis andRheumatism 60 (12): 3546-3553.

National Arthritis Foundation. 2011. www.arthritis.org. Accessed11 January 2019.

National Osteoporosis Foundation. 2010. www.nof.org. Accessed11 January 2019.

SF-36.org. 2011. www.sf-36.org. Accessed 11 January 2019.Tosteson AN, Melton LJ, Dawson-Hughes B, Balm S, Favus MJ,

Khosla S, Lindsey RL. 2008. Cost-effective osteoporosistreatment thresholds: The United States perspective.Osteoporosis International 19: 437-447.

University of California at San Diego Health Services ResearchCenter. 2011. Quality of Well-Being Scale–Self Administered(QWB-SA). https://hoap.ucsd.edu/qwb-info. Accessed 11January 2019.

U.S. Department of Health and Human Services. 2008. PhysicalActivity Guidelines for Americans. Washington, DC: U.S.Department of Health and Human Services.www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services. 2018. PhysicalActivity Guidelines for Americans, 2nd ed. Washington, DC:U.S. Department of Health and Human Services.www.health.gov/PAGuidelines/second-edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2008. Physical ActivityGuidelines Advisory Committee Report, 2008. Washington, DC:U.S. Department of Health and Human Services.https://health.gov/paguidelines/2008/report/pdf/CommitteeReport.pdf.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2018. 2018 Physical ActivityGuidelines Advisory Committee Scientific Report. Washington,DC: U.S. Department of Health and Human Services.https://health.gov/paguidelines/second-edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

2.2.3, 2.3.2, 2.5.1, 6.2.1, 6.2.2, 6.2.3, 6.2.4, 6.4, 6.4.1,6.4.2, 6.4.3, 6.4.4, 6.5.2

CHAPTER 8Cancers

OBJECTIVES

After completing this chapter, you should be able to discuss thefollowing:

»  The definition of cancer and which types are affected byphysical activity

»  The prevalence of cancers affected by physical activity»  Possible mechanisms by which physical activity can lower

cancer risk»  Physical activity guidelines for cancer prevention»  How physical activity can be a part of cancer survivorship

OPENING QUESTIONS»  What is cancer, and how can physical activity play a role in

its prevention?

»  What evidence exists that shows that physical activity canreduce cancer risk?

»  How much physical activity is sufficient to reduce cancerrisk?

»  How can physical activity help people who have survived about with cancer?

Just the mention of the word cancer evokes many images andemotions for many people. Most people have known a relative,friend, or acquaintance who has had, is currently diagnosed with, orhas died from some type of cancer. Although referring to cancer as adisease in the singular is convenient, many types exist, and they areunique. Cancer is actually a group of diseases, each with its ownrisks, etiologies, and pathologies. Cancers are defined as diseaseswith processes associated with uncontrolled abnormal cell growthand proliferation. Many cancers can recur after successful treatmentor can spread to organs and systems other than their origin (alsoknown as metastases). Many types of cancer are rapidly fatal,

whereas others offer a very positive prognosis, particularly whendiagnosed early.

Although much of the work in the area of physical activity andhealth has focused on the cardiovascular system and traditionalphysiological responses to exercise training (see chapters 2 and 5),in the past three decades, substantial evidence has emergeddemonstrating that physical activity plays an important role inpreventing certain cancers. Early physical activity and cancer studiesestablished strong evidence determining that regular physical activityhelps to prevent colon cancer and breast cancer. However, duringthe past decade, strong evidence has now emerged linking physicalactivity to the prevention of more cancers. The 2018 Physical ActivityGuidelines Advisory Committee Report concluded that in addition tocolon and breast cancer, regular moderate- to vigorous-intensityphysical activity reduces the risk of developing bladder,endometrium, esophagus, kidney, and stomach cancers. Theproposed physiological mechanisms of action by which physicalactivity contributes to cancer prevention are intriguing because theyinvolve systems in the body that exercise physiology research hasnot focused on. In addition to questions of primary prevention, agrowing body of evidence supports a role for physical activity inimproving cancer prognoses and the for the quality of life of peoplewho have cancer (U.S. Department of Health and Human Services[USDHHS], Physical Activity Guidelines Advisory Committee[PAGAC] 2018).

PREVALENCE OF CANCERSDifferent cancers have varied causes in people. Many cancers areidiopathic—meaning that the cause in a given person may never beknown. The concepts of risk factors and probability have helped ourunderstanding of cancers. For example, although cigarette smokingis one of the most insidious risk factors for lung cancer and theprobability of cancer is much higher among cigarette smokers ascompared to non-smokers, some people who have never smoked a

cigarette are diagnosed with lung cancer. Cancers are caused byboth internal factors (e.g., heredity, immune dysfunction, andabnormal metabolism) and external factors (e.g., behaviors such assmoking and a sedentary lifestyle, pollution, and radiation exposure).These factors can act alone or in synergy over time to produceuncontrolled cell growth and proliferation.

Evidence is very clear that the interaction between theenvironment and genetics is a possible trigger for cancerous cellchanges. For example, a person may have a family history (heredity)of a certain type of cancer, thus possibly carrying a genetic code thatmay increase cancer risk. That genetic disposition toward cancermay never be expressed if it does not come into contact with anenvironmental exposure (e.g., cigarette smoke); such contact,though, may trigger the expression of the gene, causing the cells tobecome cancerous.

Cancers were the second leading cause of death in the UnitedStates in 2017, affecting 40% of men and 38% of women during theirlifetimes. Only about 10 to 15% of cancers are linked to heredity; theremaining cases are thought to be related to external factors such aslifestyle or environmental factors. In the United States 1,620 peopleper day were estimated to die from cancers in 2015. Canceraccounts for 23% of all deaths in the United States (Centers forDisease Control and Prevention 2016). Globally, cancer killed anestimated 9.6 million people in 2018 (World Health Organization2018), and the rate is expected to increase to 23.6 million as a resultof the growth and aging of the world’s population (National CancerInstitute 2018b).

Notably, research has demonstrated that many cancers may bedue to health behaviors and, thus, are theoretically preventable. TheAmerican Cancer Society (2017) estimated that 45% of the total587,521 U.S. deaths from cancers in 2014 were related to lifestylefactors such as overweight and obesity, physical inactivity, unhealthyeating, and smoking. Lee and colleagues (2012) estimated that 10%

of breast and colon cancer cases globally were due to physicalinactivity (i.e., not meeting physical activity guidelines).

The economic burden of cancer is, not surprisingly, a complicatedtopic. Different cancers have different health effects—some arerapidly fatal, others are treatable but carry a long burden of illness,and still others are curable if diagnosed early. Thus, direct costs (i.e.,how much money is needed for treating the disease in the hospital,and how much money is needed to pay for physicians, nursing homeservices, and pharmaceuticals) as well as indirect costs (e.g.,changes in health-related quality of life, lost productivity due todisability and death) differ by cancer type. Age is also an importantissue. Cancers that occur later in life, on a population level, cost lessthan those in younger people. Cancers occurring in countries withmedical care delivery systems that are different from that of theUnited States have different economic costs than similar cancers inthe United States.

Many risk factors for cancers are modifiable. What are thebarriers to reducing these risks?

The American Cancer Society (2015) estimated that the economiccosts due to direct medical care of all cancers in 2015 was $80.2

billion (USD). This estimate does not include the costs resulting fromlost productivity among people living with cancer, or costs due to lostproductivity among people who died from cancer. Clearly, theeconomic burden, in addition to health and social burdens, isimportant to address as a public health problem.

Because cancers are such a significant health burden, andbecause disease surveillance is so central to public health, manyuseful sources of cancer statistics are available. These statistics areimportant in many ways, but one key way is to help us distinguishnew cases of cancer (incidence) from existing cases (prevalence).Because more people are living longer with cancers than at anyother time in history, which is due to impressive advances in therapy,the number of existing cases of cancers is on the rise (prevalence). Ifwe could not distinguish these existing cases from the new cases(incidence) we would incorrectly assume that cancer is an increasingproblem simply because more people are living longer with cancer.

One excellent resource for cancer information in the United Statesis the National Cancer Institute, one of the institutes at the NationalInstitutes of Health (NIH). The Cancer Surveillance Epidemiologyand End Results (SEER) program has been operating since theearly 1970s and is the definitive web resource for cancer mortality,incidence, and prevalence data by sites affected and overall(http://seer.cancer.gov).

CANCER RISK FACTORSBefore considering the risk factors for cancers, we should have anunderstanding of how cancer starts and progresses in general.Despite multiple types of cancers with various etiologies, the processby which normal cells change and become cancerous is thought tobe common to all cancers. In this multistage model ofcarcinogenesis, outlined in figure 8.1, a subset of normal cellsbecomes initiated for a cascade toward uncontrolled proliferation instage 1. This initiation can be the result of a genetic mutation, aspontaneous change, or an external cause. The genetic material is

altered, which makes the affected cells more likely to grow morerapidly than unaffected cells.

In the second stage of the multistage process of carcinogenesis,promotion, some of these initiated (converted) cells becomeprecancerous through additional genetic changes as a result of thealtered state they entered in the initiation stage. The promotion stageis characterized by the rapid proliferation of these altered cells.

Figure 8.1   Multistage model of carcinogenesis.Adapted from Rogers et al. (2008).

Some of the cells that have proliferated during the promotionstage will progress to the third stage of progression. In this stage,proliferating precancerous cells become full, invasive tumors, andcancer is subsequently diagnosed.

Why is this model important? The multistage model ofcarcinogenesis, which includes initiation, promotion, andprogression, allows us to hypothesize about and study the possiblemechanisms by which physical activity and other factors mayinterrupt this process and prevent cancers. Although they are stillworking largely with animal models, researchers are aggressivelystudying how physical activity may affect (and prevent) key geneticchanges and their cellular expressions at each of these three stages(Rogers et al. 2008).

A list of general risk factors associated with developing cancersfollows. Specific cancers may have additional risk factors that cancause cellular damage internally (e.g., mutations and immuneconditions), such as hormonal regulation or nutrient metabolism, orexternally, such as tobacco use, chemicals, and sun exposure. Asdiscussed earlier, even though heredity is listed here as anonmodifiable risk factor, how inherited genes are expresseddepends on interactions with environmental exposures.Modifiable Risk Factors for Cancer

Physical inactivityObesityTobacco usePoor nutrient intakeExcessive sun exposureToxic environmental exposure

Nonmodifiable Risk Factors for Cancer

AgeHeredity (genetics)Sex

Following are descriptions of the modifiable and nonmodifiablerisk factors for cancer:

• Physical inactivity. Physical inactivity is emerging as animportant risk factor for several prevalent cancers; meeting physicalactivity guidelines may lower the risk of developing these cancers.

• Obesity. As with CVD risk, having a BMI greater than or equal to25 kg/m2 (overweight) or 30 kg/m2 (obesity) significantly increasesthe risk of most cancers.

• Tobacco use. Chronic smoking is associated with lower levels ofaerobic capacity and functional health. Tobacco use was associated

with 169,000 cancer deaths in 2009 and is the main risk factorassociated with cancers of the lung and bronchus.

• Poor nutrient intake. The consumption of a diet that is low inessential nutrients (e.g., those found in fresh fruits and vegetables),practicing risky behaviors (e.g., excessive alcohol intake), or both,can increase the risk of cancers.

• Sun exposure. Excessive exposure to the sun’s rays and indoortanning (i.e., nonionizing radiation) are the primary risk factorsassociated with skin cancers.

• Toxic environmental exposure. Long-term exposure toenvironmental toxins such as chemicals, ionizing radiation, andinfectious diseases can increase the risk of most cancers.

• Age. The risk of developing cancer increases the longer onelives because most cancers develop over time from damaged genes.The majority of cancers (>70%) occur in adults who are over 55years of age.

• Heredity (genetics). Although cancer risk depends somewhat ongenetics, engaging in positive behaviors such as being physicallyactive, eating healthily, maintaining a healthy weight, and minimizingrisky activities can lessen overall risk by improving functions such ascirculation, ventilation, bowel transit time, energy balance andimmune function, and DNA repair (Thune and Furberg 2001).

• Sex. Some cancers are sex specific. Prostate cancer in menand reproductive system cancers in women (ovarian, endometrial)are examples of sex-specific cancers.

KINESIOLOGY AND CANCERSAs noted in the 2018 PAGAC, a relationship between physicalactivity and reduced cancer risk has been found consistently forbreast and colon cancers over the past two decades (see table 8.1).More recently, it has been determined that there is also strongevidence linking physical activity to the prevention of cancers of thebladder, endometrium, esophagus, kidney, and stomach.

Additionally, there is some evidence suggesting an associationbetween regular physical activity (as compared to inactivity) and alowered risk for lung cancer; however, this evidence is not yetconclusive. Emerging research is currently studying potential linksbetween physical activity and blood, head and neck, pancreas,prostate, and ovary cancers, but to date, little evidence supportsrelationships between physical activity and risks for other cancers,beyond those cancers mentioned in this chapter.

Table 8.1   Estimated New Cases and Deaths per Year (2018) fromCancers for Which Physical Activity is a Protective Factor

Type of cancer

Estimated new casesnumber (% of all newcancer cases)

Estimated deathsnumber (% of allcancer deaths)

Bladder 81, 190 (4.7%) 17,240 (2.8%)

Breast (female) 266,120 (15.3%) 40,920 (6.7%)

Colon and rectum 140,250 (8.1%) 50,630 (8.3%)

Endometrium (uterine) 63,230 (3.6%) 11,350 (1.9%)

Esophagus 17,290 (1.0%) 15,850 (2.6%)

Kidney & renal pelvis 65,340 (3.8%) 14,970 (2.5%)

Stomach (gastric) 26,240 (1.5%) 10,800 (1.8%)

Total for cancers for which PAis a risk factor

659,660 (38.0%) 161,760 (26.5%)

Total for all cancers 1,735,350 (100%) 609,640 (100%)

Data from the National Cancer Institute (2018).

The positive effects of physical activity for cancer survivorsare becoming clearer each year with new research.

The earliest and strongest evidence of a link between physicalactivity and cancer showed an inverse relationship between cancerof the colon and physical activity. Today, there is extensive andstrong evidence demonstrating that high amounts of recreational,occupational, and total physical activity help prevent thedevelopment of colon cancer. Moreover, Harris and colleagues(2009) and the World Cancer Research Fund International andAmerican Institute for Cancer Research (2011) have found strongevidence indicating that association between colon cancer and

physical activity is best described as a dose-response. This meansthat the higher the level (dose) of regular physical activity, the lowerthe risk of developing colon cancer. Finally, there is sufficient andstrong evidence demonstrating that both men and women benefitfrom the positive effects of physical activity on colon cancer riskreduction. Many studies using various designs and types ofparticipants have been conducted over the years. The most recentlypublished meta-analysis (a study compiling findings from the beststudies of a given topic) on colon cancer and physical activity wasconducted by Liu and colleagues (2016). They concluded that, aftercontrolling for the differences in study design and other factors, thepeople who were most physically active had a 19% lower risk ofdeveloping colon cancer than those who were least active.

The fact that higher levels of physical activity are associated withlower risks of breast cancer is an exciting one, particularly given theprevalence of breast cancer among women. About one in eightwomen living today will be diagnosed with breast cancer during herlifetime. With recent time trends for the disease being relativelystable, breast cancer is clearly an important health problem toaddress.

Like with colon cancer, an extensive body of various scientificstudies have been conducted over the years, demonstrating a clearlink between physical activity and breast cancer risk. A recent meta-analysis by Wu and colleagues (2017) found the average risk ofbreast cancer to be 10 to 15% lower among the most physicallyactive women compared to similarly inactive women. The amount ofphysical activity needed to reduce the risk of breast cancer has beenestimated to be the equivalent of brisk walking 45 to 60 minutes ormore per day, five or six days per week (McTiernan 2008). Recentstudies have examined the protective effect of physical activity onbreast cancer risk reduction by looking separately at pre- versuspost-menopausal women. Wu and colleagues found that the mostphysically active pre-menopausal women have a 14 to 31% lowerrisk of developing breast cancer than inactive pre-menopausal

women. Likewise, the most physically active post-menopausalwomen have an 8 to 13% lower risk of developing breast cancerthan their inactive counter parts. These findings are interesting,because they reveal that the risk reduction for breast cancer due tophysical activity may be greater among pre-menopausal women.However, other researchers have conducted similar studies, findingno substantial differences in risk of breast cancer by menopausalstatus. The one clear message is that engaging regularly in physicalactivity helps all women, regardless of life-stage, in preventing breastcancer. Moreover, strong evidence from several studies is also nowavailable demonstrating a dose-response relationship betweenlevels of physical activity and breast cancer risk reduction: The morephysically active a woman is, the lower her risk of developing breastcancer. The field of study of cancer and physical activityepidemiology has evolved rapidly over the past 10 years. It is nowwell established that physical activity is a critical protective factor fora variety of cancers. Strong evidence from several meta-analyses isnow available quantifying the protective effects of physical activity onother cancers beyond those of the colon and breast sites. Keimlingand colleagues (2014) report a 20% lower risk of bladder canceramong highest versus lowest activity groups. Keum and colleagues(2014) found that women with the highest levels of physical activityhad an 18% lower risk of endometrial (uterine) cancer than those inthe most inactive category. Behrens and colleagues (2014)conducted a comprehensive meta-analysis of the effect of physicalactivity on esophageal cancer and found that highly active peoplehave a 21% lower risk of developing esophageal adenocarcinoma. In2013, Behrens and colleagues also examined the evidence on theeffect of physical activity on renal cancer (of the kidney). Theyestimated a 12% lower risk of kidney cancer among individuals withthe highest levels of physical activity, as compared to those with thelowest levels. Finally, in 2014, Singh and colleagues reported a 19%lower risk of gastric (stomach) cancer among very active people incontrast to those with very low levels of physical activity. Other

studies are underway examining the potential role of physical activityon preventing even more cancers.

Friedenreich and Cust (2008) showed that all types of physicalactivity were associated with a lower risk of breast cancer—aremarkably consistent finding. Women who were more physicallyactive in their jobs or who had a measurable amount of physicalactivity while traveling had a lower risk of breast cancer. Womenparticipating in recreational physical activity seemed to have an evenlower risk. Why might this be?

Although strong scientific evidence supports a dose-responserelationship between physical activity and lower risk of severalcancers, the specific physiological mechanisms by which this lowerrisk might be operating remain under study. In the last 15 years,researchers have started to study the biological mechanisms of, andlinks between, the specific dose-response relationships betweenphysical activity and cancer risks. Some of the chronic exercise-related adaptations that have been reported to lower the risks forcancers are shown in the highlight box Potential MechanismsThrough Which Physical Activity Lowers Cancer Risk.

PHYSICAL ACTIVITY EXPOSURE IN CANCER STUDIESCancer is an extremely difficult disease to study in free-living populations. This is especially true in studies ofphysical activity exposure and cancer risk. The multistagemodel of carcinogenesis can occur fairly rapidly (e.g.,over the course of a few years) or over a lifetime. This

means that knowing when the exposure to a risk factor suchas physical inactivity occurred is very important. Forexample, several researchers have hypothesized thatphysical activity may be more important for cancerprevention in certain periods of life than in others(e.g., it may be more important during early adulthoodthan during later adulthood, which is closer to when thedisease develops). Others take the contrary view that aconstant and sustained exposure to physical activity is

most important—that lifetime exposure to physical activityconfers the lower risk. Either way, long-term studies thatfollow people over their lifetimes are critical foranswering these questions. What do you think? Would you bewilling to be followed throughout your life to participatein such a study?

Most of the contributions of kinesiology to our understanding ofcancer mechanisms come from exercise physiology. Researchlaboratories around the world have focused attention on howexposure to physical activity may block key steps in the multistagecarcinogenesis process. Biomechanical and behavioral factors,although important, have not been identified as central to themechanisms of physical activity that affect the development ofcancer.

POTENTIAL MECHANISMS THROUGH WHICHPHYSICAL ACTIVITY LOWERS CANCER RISK

Avoidance of weight gain or weight loss

Reduced insulin resistance

Lower systemic low-grade inflammation

Lower colon transit time

Lower production of sex hormones

Improved immune function

The scientific literature seems to support at least six likelyexplanations—through two different pathways—of how physicalactivity reduces the risk of cancers. One pathway is an indirect one:Physical activity affects body composition and adiposity. Thesechanges in body composition lower cancer risk indirectly bychanging factors associated with higher body fatness, such aspositively affecting biomarkers of systemic inflammation (a marker

for several types of chronic disease including cancers), improvinginsulin resistance (i.e., improving the ability of the hormone insulinto clear glucose from the body), increasing blood insulin levels, andlowering the production of sex hormones (estrogens andandrogens).

Physical activity can also reduce the risk of cancer directly (i.e.,not through reducing adiposity). The direct physiological effects ofphysical activity on skeletal muscle improve insulin resistance.Physical activity has also been shown (independent of adiposity) toimprove levels of sex steroid hormones (androgens and estrogens),improve biomarkers of low-grade inflammation, and improve immunefunction. Further, physical activity can work mechanically to reducecolon transit time, thus reducing the time potential carcinogeniccompounds are in contact with the digestive system. This is one ofthe key hypothesized mechanisms for physical activity preventingcolon cancer.

It is fairly clear that sex hormones are important in cancer risk.Higher levels of circulating estrogens and androgens place womenat higher risk of breast cancer. This appears to be especially true forpostmenopausal women. Exercise training has been shown todecrease circulating sex hormones directly and through fat loss. Thepositive effects of physical activity on sex hormones can be expectedas a result of moderate-intensity as well as vigorous-intensityphysical activity.

Higher insulin resistance has been associated with several typesof cancer, and insulin has been shown to increase cell proliferationcoincident with the multistage model of carcinogenesis (see figure8.1). Physical activity and exercise very clearly lower insulinresistance (allowing for glucose to be cleared from the body moreefficiently) via improved cellular metabolism both acutely (i.e.,immediately after a single exercise bout) and chronically (i.e., amongthose who are habitually physically active). Interestingly, this effecthas been shown for aerobic physical activity as well as resistancetraining.

The interrelationship among immunity, cancer, and physicalactivity is a complicated topic that researchers are only just nowstarting to investigate. Because of the uncontrolled differentiationand multiplication of cells that characterize most cancers, the body’simmune system has long been a target for understanding cancerprevention and treatment. This is because we normally depend onthe immune system to isolate and eliminate foreign or abnormalcells.

Small, short-term exercise training studies have been shown toincrease individual markers of immune function, and this responsehas been maintained for several hours after the cessation ofexercise. Further, a positive dose-response association betweenphysical activity intensity and immune function has been shown;more improvement has been observed with higher-intensity activity.The longer-term association with chronic exercise is unclear.However, bouts of vigorous-intensity exercise (such as thoseperformed by elite athletes who may overtrain) over time mayactually lower immune function and increase the risk of acuteinfections such as those of the upper respiratory tract. Clearly, muchresearch is needed on this promising topic.

SCREENING FOR EARLY DIAGNOSIS OF CANCERScreening is an extremely effective way to catch severaltypes of cancers early. A variety of regular screeningtests are used to detect precancerous growths and stage 1cancers. (Cancer occurs in four stages: stage 1 is early-stage cancer, and stage 4 is late-stage, or advanced). Asnoted in “Cancer Facts and Figures” (American CancerSociety 2018), cancers of the cervix, colon, and rectumcan be prevented by removing precancerous tissue. Cancersof the breast, colon, rectum, cervix, prostate, oralcavity, and skin can also be diagnosed through screening.Self-screenings for many cancers (e.g., breast and skin)are valuable for personal awareness and may result in theearly detection of disease.

PHYSICAL ACTIVITY AMONG CANCER SURVIVORSIs there a benefit to being physically active after being diagnosedwith cancer, perhaps during and after treatment? With improvedcancer treatments and earlier, more effective diagnostic techniques,more and more people are living with cancer. In 2016, an estimated15 to 16 million people in the United States were living with cancer orhad survived a bout of cancer. This number is expected to becomelarger, and increase to about 20 million cancer survivors by 2026(National Cancer Institute, 2018b).

A cancer diagnosis is a difficult situation filled with manypsychological and physiological changes—as a result of both thedisease and the therapeutic regimens used to control the disease.Chemotherapy, radiation, and surgery are standard cancertreatments, and all can negatively affect the body in the quest toreduce or eliminate a cancerous tumor. Hormone therapy and steroidtreatments that accompany some cancer treatments can also havedeleterious effects. Issues such as fatigue, lymphedema (i.e.,localized fluid retention secondary to radiation therapy),cardiorespiratory fitness, muscular strength and endurance, qualityof life, self-esteem, and safety (i.e., risk of adverse events) are mostimportant to cancer survivors.

In 2010, Speck and colleagues published a comprehensive reviewof studies of cancer survivors (n = 6,838). These researchersreviewed 82 studies that examined some effect of exercise trainingor physical activity during and after cancer treatments.Overwhelmingly, breast cancer has been the cancer most frequentlyexamined for benefits of physical activity. Because cancers areunique diseases, however, the effects of physical activity on breastcancer survivors may not be attributable to survivors of colon cancer,endometrial cancer, prostate cancer, or other types of cancer.

A listing of the health benefits of physical activity for cancersurvivors is shown in table 8.2. Factors are categorized according towhen their effects were studied: during or after cancer treatment.Although dozens of health and physiological outcomes have been

investigated, the factors listed in the table are those that have beenconsistently shown to result from increased exercise or physicalactivity across several studies.

Table 8.2 suggests that physical activity has some consistentpositive effects on several physical and psychological parametersamong cancer survivors. Clear and substantial gains in upper andlower body strength can be expected among cancer survivors aftertreatment, and small to moderate gains can be expected even duringtreatment. Although observed effects are not large for otherphysiologic outcomes, this emerging evidence gives substantialcredibility to the belief that physical activity programming should bepart of cancer survivors’ therapy.

PHYSICAL ACTIVITY GUIDELINES FOR CANCERPREVENTIONAt least 300 years ago, scientists first suggested that physicalactivity plays a role in cancer prevention; however, specificmechanisms of how this may happen and recommendations aboutthe levels required for prevention have been articulated only in thepast 15 years or so.

Table 8.2   Summary of Physical Activity Effects Among CancerSurvivors

ParameterImprovement after cancertreatment

Improvement during cancertreatment

Upper body strength Large Small to moderate

Lower body strength Large Small to moderate

Breast cancer–specificconcerns

Large —

Cardiorespiratoryfitness

Small to moderate Small to moderate

Fatigue Moderate Small to moderate

Overall quality oflife

Small to moderate Small to moderate

Anxiety — Small to moderate

Self-esteem — Small to moderate

Physical activityparticipation

Small to moderate Small to moderate

Symptoms and sideeffects*

Small to moderate —

*Symptoms and side effects include nausea, lymphedema, and pain.Data from Speck et al. (2010).

SCIENTIFIC EVIDENCEThe Physical Activity Guidelines Advisory Committee (USDHHS,PAGAC 2018) noted strong scientific evidence of an inverserelationship between participation in physical activity and exerciseand the risk of breast, colon, bladder, endometrial, esophageal,kidney, and stomach cancer. The strongest evidence, includingevidence of a dose-response relationship, is for breast and coloncancer. Participation in regular physical activity and exercise canlower the risk of colon cancer by 19% and the risk for breast cancerby 12%. The association is strong regardless of sex or age andmoderate when race and ethnicity are taken into consideration.

LEADER PROFILEAndrea Ramirez Varela, MD, MPH, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?I entered the field of medicine in 2004 with the goal ofnot only becoming a dedicated physician who treats diseasebut one who also understands that health and disease occurin the complex interplay between individual, biological,environmental, and socioeconomic factors.

After being exposed to the different specialty areas ofmedicine, I sought out experiences that would help mechoose the field that would allow me to best serve mycountry (Colombia) and make a difference by helpingimprove health conditions. Specifically, I worked as ateaching assistant for the undergraduate epidemiologycourse at Universidad de los Andes, in Bogotá, Colombia,and I volunteered at three health care brigades, whichaimed to prevent illness through health education andprovide medical consultation to treat common diseases.

In 2010, I graduated from the Universidad de los AndesSchool of Medicine. By this point, I was certain that Iwanted to dedicate the rest of my medical career and lifeto disease prevention and health promotion.

Medical programs in Colombia require a year of socialservice after graduating, which can be done in a clinicalsetting or by doing research. I chose research in the areaof chronic disease prevention. Cardiovascular disease iscurrently the leading cause of death in Colombia whilecancer is now one of the top 10 causes of death. For ayear I worked on various public health research projects,including coordinating the Colombian site for theInternational Physical Activity and the EnvironmentNetwork (IPEN), a multicountry study directed by Dr. James

Sallis of the University of California, San Diego. Theobjective of the IPEN project was to determine theassociation between built-environment characteristics andphysical activity in adults in 14 countries worldwide. Imanaged the ethical component of the project, supervisedthe fieldwork, made cultural adaptations to the studyinstruments (e.g., surveys such as the InternationalPhysical Activity Questionnaire [IPAQ] and theNeighborhood Environment Walkability Scale,accelerometers, and anthropometric measurement tools),conducted built-environment measurements, managed dataquality control, conducted statistical analyses, andprepared manuscripts for publications. My goal in theproject was to gain the skills necessary to work as aspecialist and researcher in future preventive medicineprojects. This experience showed me that prevention aloneis a highly effective intervention to maintain humanhealth.

In 2011, I became the project manager for the Colombiansite of the International Study of Childhood Obesity,Lifestyle and Environment (ISCOLE), led by PeterKatzmarzyk from the Pennington Biomedical Research Centerin Baton Rouge, Louisiana. The project aimed to determinethe relationship between lifestyle characteristics,obesity, and weight gain in 10-year-old children across 12countries. I was excited to be part of this project due toits focus on childhood obesity, which is a growing problemin Colombia, despite the lingering prevalence of childhoodundernutrition. The project gave me important insight intothe ethical aspects of research involving children,measures of the built environment around schools, and howto apply food frequency questionnaires. The experiencealso made my career choice of preventive medicine morepronounced.

In addition to my work in clinical and communitysettings, I was involved in coordinating short researchcourses as part of a capacity-building project led by Dr.Michael Pratt of the Centers for Disease Control andPrevention (CDC). I helped coordinate the course inSantiago, Chile, in January 2011, and co-taught a workshopon physical activity measurement using accelerometers. Iwas also part of the CDC think tank on Physical Activityand Behavior Change, which took place in December 2011 in

Bogotá, Colombia. Also, in September 2012, I participatedas an organizer and speaker for a national course led bythe CDC, Universidad de los Andes, and Coldeportes, agovernment entity in Colombia. The course content includedpolicies and programs for chronic disease preventionthrough physical activity, and was an excellent example ofcooperation between government, private, and academicinstitutions to train physical activity promotersthroughout the country.

In 2013, I received a scholarship to attend the PhysicalActivity and Public Health Course for Practitionersdirected by Dr. Russell Pate in Utah, then started aMaster of Public Health program at Universidad de losAndes. In 2014, I began working as the coordinator of theGlobal Observatory for Physical Activity—GoPA!.

Early in 2015, I moved to Brazil and started a PhDprogram in epidemiology in the Postgraduate Program inEpidemiology at Universidade Federal de Pelotas (UFPeL),supervised by Dr. Pedro Hallal from UFPeL and Dr. MichaelPratt from University of California, San Diego. Mydoctoral research was based on the GoPA! project and fromthat moment physical activity surveillance became my mainarea of research.

During 2017, I was a research scholar in the Departmentof Family Medicine and Public Health at University ofCalifornia, San Diego. During my PhD program I

participated as a research assistant in the 2016 Lancetseries on physical activity, and as a speaker in globalresearch and practice courses for physical activity andpublic health in Mexico, Brazil, and Colombia.

Did any one person have a major influence on your career?How?Working in the physical activity and public health fieldhas allowed me to meet not only outstanding researchersbut also wonderful friends. I would like to acknowledgeMichael Pratt and Pedro Hallal, my PhD supervisors, whohave taught and mentored me over many years. Their vision,support, and motivation helped incredibly on my path tobecoming an epidemiologist and researcher. Mike andPedrinho are visionaries who believe in the leadership ofLatin American women in the physical activity and publichealth field.

It has been a great pleasure to work with them and Ilook forward to doing so for many more years. IsaacNewton’s quote describes the major influence Mike andPedro have had on my career: “If I have seen further thanothers, it was only by standing upon the shoulders ofgiants.”

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?My research interests are global physical activityepidemiology and surveillance; global public healthcapacity for chronic disease prevention and physicalactivity promotion; and translation research, especiallyin Latin America.

I translate research into practice in my daily work. Thecollaboration and work that is done with every countryrepresentative in GoPA! allows me to disseminate and putinto practice new and acquired knowledge with the GoPA!community. Furthermore, I am in frequent contact with theGoPA! and the International Society for Physical Activityand Health (ISPAH) network at the local and regionallevels.

Why do you do what you do?I am passionate about my work and research area. I feelvery excited and enthusiastic about being in contact withand learning from people all around the world.

What are two key issues that must be addressed by 2030?

1. Capacity building (i.e., the process of developingknowledge and skills among individuals and

organizations to carry out self-sustained public

health research and practice in their own settings),

funding opportunities and research positions favoring

women as principal investigators, studies on

interventions, policy, translation, and scalability.

2. Stronger and more integrated and multidisciplinarycollaboration between policy makers and researchers,

as is being done by global initiatives like GoPA! and

Global Action Plan for Physical Activity (GAPPA).

A substantial amount of evidence indicates a dose-responseassociation between physical activity and exercise and a lower riskof developing colon or breast cancer, which is consistent with therecommendation of 30 to 60 minutes of moderate- to vigorous-intensity physical activity every day. Data for this effect are strongestin relation to aerobic leisure time (recreational) physical activity. Agrowing body of strong evidence suggests that breast cancersurvival (i.e., quality of life and fitness) is associated withparticipation in regular physical activity and exercise.

GUIDELINESThe levels of physical activity associated with cancer risk reductioncan be attained by following the Physical Activity Guidelines forAmericans as described for cardiorespiratory health (see chapter 5)and musculoskeletal health (see chapter 7). Adults should engage in150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic activity per week, or an equivalent amount of mixedmoderate-intensity and vigorous-intensity aerobic activity. Theyshould also try to participate in muscle-strengthening activitiesinvolving the major muscle groups on two days or more per week.

Cancer survivors who engage in physical activity and exercisecan reduce their risks for new chronic diseases, and participationmay reduce the adverse effects of cancer treatment. Cancersurvivors should consult with their health care providers to verify thattheir physical activity or exercise plans are consistent with theircurrent physical abilities and health status.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

Cancers are disease processes associated with uncontrolledabnormal cell growth and proliferation. Cancers are causedby both internal factors (e.g., heredity, immune dysfunction,abnormal metabolism) and external factors (e.g., behaviorssuch as smoking and a sedentary lifestyle, radiationexposure). These factors can act alone or in synergy overtime to produce carcinogenesis.Common risk factors for most cancers include age, physicalinactivity, obesity, heredity, sex, tobacco use, sun exposure,and poor nutrient intake.The risk of colon, breast, bladder, endometrial, esophageal,kidney, and stomach cancer can be reduced by participatingin at least 150 minutes of moderate-intensity physical activityper week. More physical activity results in higher riskreduction for breast and colon cancer.Cancer survivors who engage in physical activity andexercise can reduce their risks for new chronic diseases, andparticipation may reduce the adverse effects of cancertreatment.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYAmerican Cancer Society. 2017. More than 4 in 10 Cancers and

Cancer Deaths Linked to Modifiable Risk Factors (2014).https://www.cancer.org/latest-news/more-than-4-in-10-cancers-

and-cancer-deaths-linked-to-modifiable-risk-factors.html.Accessed 14 October 2018.

American Cancer Society. 2018. Cancer Facts and Figures 2018.https://www.cancer.org/research/cancer-facts-statistics/all-cancer-facts-figures/cancer-facts-figures-2018.html. Accessed14 October 2018.

American Cancer Society. 2015. Economic Impact of Cancer.https://www.cancer.org/cancer/cancer-basics/economic-impact-of-cancer.html. Accessed 20 October 2018.

Behrens, G., & Leitzmann, M. F. 2013. The Association BetweenPhysical Activity and Renal Cancer:Systematic Review andMeta-analysis. British Journal of Cancer 108(4): 798.

Behrens G, Jochem C, Keimling M, Ricci C, Schmid D, LeitzmannMF. 2014. The association between physical activity andgastroesophageal cancer: Systematic review and meta-analysis. European Journal of Epidemiology 29 (3): 151-170.

Centers for Disease Control and Prevention. 2016. LeadingCauses of Death. https://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm. Accessed 14 October 2018.

Friedenreich CM, Cust AE. 2008. Physical activity and breastcancer risk: Impact of timing, type and dose of activity andpopulation subgroup effects. British Journal of Sports Medicine42: 636-647.

Harris DJ, Atkinson G, Batterham A, George K, Tim Cable N,Reilly T, Haboubi N, Renehan AG, Colorectal Cancer, Lifestyle,Exercise and Research Group. 2009. Lifestyle factors andcolorectal cancer risk: A systematic review and meta-analysisof associations with leisure‐time physical activity. ColorectalDisease 11 (7): 689-701.

Keimling M, Behrens G, Schmid D, Jochem C, Leitzmann MF.2014. The association between physical activity and bladdercancer: Systematic review and meta-analysis. British Journal ofCancer 110 (7): 1862.

Keum N, Ju W, Lee DH, Ding EL, Hsieh CC, Goodman JE,Giovannucci EL. 2014. Leisure‐time physical activity andendometrial cancer risk: Dose–response meta‐analysis ofepidemiological studies. International Journal of Cancer 135(3): 682-694.

Lee IM, Shiroma EJ, Lobelo F, Puska P, Blair SN, Katzmarzyk PT,Lancet Physical Activity Series Working Group. 2012. Effect ofphysical inactivity on major non-communicable diseasesworldwide: An analysis of burden of disease and lifeexpectancy. The Lancet 380 (9838): 219-229.

Liu L, Shi Y, Li T, Qin Q, Yin J, Pang S, Nie S, Wei S. 2016.Leisure time physical activity and cancer risk: Evaluation of theWHO’s recommendation based on 126 high-qualityepidemiological studies. British Journal of Sports Medicine 50(6): 372-378.

McTiernan A. 2008. Mechanisms linking physical activity withcancer. Nature Reviews Cancer 8: 205-211.

National Cancer Institute. 2011. Probability of Breast Cancer inAmerican Women.www.cancer.gov/cancertopics/factsheet/detection/probability-breast-cancer. Accessed 18 October 2018.

National Cancer Institute. 2018a. Cancer Stat Facts.https://seer.cancer.gov/statfacts. Accessed 18 October 2018.

National Cancer Institute. 2018b. Cancer Statistics.https://www.cancer.gov/about-cancer/understanding/statisticsAccessed July 16 2019

Rogers CJ, Colbert LH, Greiner JW, Perkins SN, Hursting SD.2008. Physical activity and cancer prevention: Pathways andtargets for intervention. Sports Medicine 38: 271-296.

Singh S, Varayil JE, Devanna S, Murad MH, Iyer PG. 2014.Physical activity is associated with reduced risk of gastriccancer: A systematic review and meta-analysis. CancerPrevention Research 7 (1): 12-22.

Speck RM, Courneya KS, Masse LC, Duval S, Schmitz KH. 2010.An update of controlled physical activity trials in cancersurvivors: A systematic review and meta analysis. Journal ofCancer Survivorship 4: 87-100.

Thune I, Furberg AS. 2001. Physical Activity and Cancer Risk:Dose-Response and Cancer, all sites and site-specific.Medicine & Science in Sports and Exercise 33: S530-S550.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2008. Physical ActivityGuidelines Advisory Committee Report, 2008. Washington, DC:U.S. Department of Health and Human Services.https://health.gov/paguidelines/2008/report/pdf/CommitteeReport.pdf.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2018. 2018 Physical ActivityGuidelines Advisory Committee Scientific Report. Washington,DC: U.S. Department of Health and Human Services.https://health.gov/paguidelines/second-edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

World Cancer Research Fund International, American Institute forCancer Research. 2011. Continuous Update Project Report:Food, Nutrition, Physical Activity, and the Prevention ofColorectal Cancer. http://wcrf.org/sites/default/files/Colorectal-Cancer-2011-Report.pdf. Accessed 11 October 2018.

World Health Organization. 2018. Cancer: Key Facts.https://www.who.int/news-room/fact-sheets/detail/cancer.Accessed July 16 2019.

Wu Y, Zhang D, Kang S. 2013. Physical activity and risk of breastcancer: A meta-analysis of prospective studies. Breast CancerResearch and Treatment 137 (3): 869-882.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST

This chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.4.2, 2.1.1, 2.2.1, 2.2.3, 2.3.3, 3.2.1, 3.2.2, 6.1.4,6.1.5, 6.2.1, 6.4.1, 6.4.3

CHAPTER 9Brain Health

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The prevalence and economic costs of brain and mentalhealth disorders and related health challenges

»  The factors associated with common brain and mentaldisorders, and how they are generally assessed

»  How physical activity affects cognition, quality of life,depression, anxiety, and sleep

»  The relationship of physiological adaptations to mentalhealth

»  The physical activity guidelines and supporting evidencerelated to brain health

»  Physical activity recommendations for brain health

OPENING QUESTIONS»  Can regular physical activity have a positive effect on brain

health? If so, how?

»  Can regular participation in physical activity prevent age-related declines in cognitive function and dementia?

»  Can physical activity help improve our quality of life?»  What are the associations among physical activity, mood,

depression and anxiety?

»  Does participation in regular physical activity improvesleep?

»  How much physical activity is consistent with good brain andmental health?

Have you ever noticed that exercising helps you forget about aproblem that was causing you a great deal of mental stress, at leastfor a little while? Do you feel calmer or happier after a visit to thegym? What factors in your life cause you stress? Does regularphysical activity and exercise help reduce or control your stresslevels? Have you noticed that you tend to focus better in school rightafter having exercised? Have you ever known someone who wasaddicted to exercise and noticed the adverse psychological effects ofthat addiction? All of these questions are related to the relationshipbetween being physically active and good mental health.

Because so much attention has been focused on the physicalhealth benefits of physical activity, we know much less about brainand mental health benefits. Although most people may assume thatphysical activity enhances mental well-being, evidence of thebiological mechanisms that explain the effects of physical activity on

brain health have only begun to emerge more strongly over the past10 years. The scientific evidence does support the importance ofmaintaining physical activity for several aspects of brain health,including cognition (e.g., attention or memory) and conditionsassociated with cognitive decline (e.g., Alzheimer’s), quality of life,mood-related disorders (anxiety, depression), and sleep quality.(U.S. Department of Health and Human Services [USDHHS],Physical Activity Guidelines Advisory Committee [PAGAC] 2018).This chapter addresses the concepts related to physical activity andbrain health at large, and gives background information on thescientific evidence concerning the relationships between physicalactivity and brain health.

PREVALENCE AND ECONOMIC COSTS OF BRAIN HEALTHDISORDERSWhat is brain health and is it the same as mental health? The 2018Physical Activity Guidelines Advisory Committee adopted the termbrain health in preference to mental health. The term brain healthencompasses both the behavioral and biological aspects of thebrain, as well as the more subjective experiences that result from thebrain’s function. Therefore, brain health refers to aspects typicallythought of as being part of mental health (i.e., those referring to themind and its well-being, such as anxiety), as well as to conditionsknown to result primarily from physical and chemical reactions in thebrain (e.g., schizophrenia). When thinking specifically about mentalhealth, we may each have different ideas about the definitions of“good” mental health and “bad” mental health. The World HealthOrganization (WHO) has defined mental health as a state of well-being in which every individual realizes his or her own potential, cancope with the normal stresses of life, can work productively andfruitfully, and is able to make a contribution to her or his community(WHO 2014).

Brain health as a whole is an essential part of overall health andwell-being, and brain and mental disorders or problems can limit

people’s ability to obtain or maintain functional health. The numberand types of brain and mental disorders are numerous and theirprevalence increases as people age. Such disorders includeemotional and behavioral symptoms as described in the Diagnosticand Statistical Manual of Mental Disorders, Fifth Edition (AmericanPsychiatric Association 2013) and the International Classification ofDiseases (ICD) (WHO 2018). Common brain and mental healthdisorders include schizophrenia, dementia, depression, anxietydisorders, substance dependence, and substance abuse. Thematerial in this chapter is limited to common brain and mental healthdisorders and problems that have been addressed by a strong oremerging body of research in the relevant literature.

Understanding the prevalence of common brain and mental healthdisorders is difficult largely due to the cultural stigma associated withbeing diagnosed with these conditions, difficulties people may havein seeking treatment, and differences in assessing the severity of adisorder. Other issues, such as a lack of health insurance, furthercompound the problem of getting stable national and internationalestimates of the scope of the problem. The best informationavailable in the United States suggests that common mental healthconditions affect 18.3% of American adults in any one year(USDHHS, National Institute of Mental Health [NIMH] 2016). Thispercentage was the equivalent of 44.7 million Americans in 2016.

Brain and mental health disorders were one of the five most costlymedical conditions in the United States from 1996 to 2006 (Soni2009). The number of people associated with these costs almostdoubled from 19.2 million to 36.2 million in 10 years. ForAlzheimer’s disease alone, the Alzheimer’s Association estimatedhealth care costs of $259 billion (USD) in 2017. Given the projectedpopulation growth patterns for Americans over the age of 65 in thenext few decades, it is expected that costs resulting from Alzheimer’sdisease and other types of dementia may account for about $758billion in 2050. Similarly, the total economic costs of major

depressive disorder alone were estimated at $210.5 billion dollarsper year in the United States in the year 2000.

The largest component of the economic burden resulting frombrain and mental health disorders (50%) is derived from lost workproductivity due to depression (Greenberg et al. 2015). In 1990, theestimated economic cost of anxiety disorders in the United Stateswas $46.6 billion, which accounted for 31.5% of the totalexpenditures for mental illness (Dupont et al. 1996). Obviously, thosecosts have most likely increased dramatically, although the actualcosts in today’s dollars have not been reported.

COMMON BRAIN HEALTH CONDITIONSFollowing are common brain disorders or problems that have beenstudied in relation to physical activity:

Cognition and age-related decline in cognitive functionMood disordersAnxiety disordersPsychological distressLow self-esteemEating or exercise-related disordersSleep disorders

Basically, cognitive function refers to our ability to think. Itbroadly encompasses our brain’s ability to process, select,manipulate, or store information. Our ability to perform well at school,to learn new concepts and remember key information, and to stay ontask without losing focus are a reflection of good cognitive health.

Age-related decline in cognitive function refers to negativechanges that occur over time in the ability to process, select,manipulate, or store information— affecting both behavior andfunctional ability. Central nervous system (CNS) disordersassociated with genetics and aging that have been linked to brainand mental health disorders include multiple sclerosis and dementia

(i.e., a loss of brain function that affects memory, thinking, language,judgment, and behavior—Alzheimer’s and Parkinson’s areconsidered types of dementia).

Mood disorders include depression, bipolar or manic–depressivedisorders, medical conditions related to mood changes, andsubstance-induced mood disorders (American PsychiatricAssociation 2013). Depression can be classified as mild (also knownas dysthymia) or as major depressive disorder (MDD). Dysthymia,defined as having mild depression symptoms for the past two years,affects 1.5% of the U.S. adult population. In addition, 6.7% of U.S.adults and 12.8% of adolescents (ages 13 to 18) experienced atleast one episode of MDD in 2016. Adolescents in the United Stateshave a lifetime combined prevalence of 11.2% for dysthymia andMDD (USDHHS, NIMH 2011, 2017a, 2017,).

The symptoms of depression are diverse and can include difficultyconcentrating and making decisions, a loss of interest in hobbies andactivities, feelings of hopelessness and helplessness, insomnia, andeven thoughts of suicide. The worries that are accompanied bydepressive symptoms can also lead to physical symptoms such asfatigue, headaches, muscle tension and aches, trembling, twitching,irritability, sweating, hot flashes, and difficulty swallowing.Depression can leave a person emotionally numb or suicidal, andmay be related to other factors such as abuse of alcohol or drugs,phobias, obsessions, and preoccupation with physical challenges.Periodic feelings of mild depression are normal for us all, and can becaused by grief or a medical condition. However, depression ormood disorders that persist beyond two months may indicate majormood change problems.

Anxiety can be broadly defined as a condition of nervousness,uneasiness, or apprehension about a future event or events. Anxiety,although a predictable part of everyday life, over time can become amental disorder that can hinder daily functional abilities. Anxiety isusually classified as either state anxiety or trait anxiety. Stateanxiety refers to a person’s existing or current emotional state, and

refers to the type of temporal anxiety (unpleasant feelings) a personexperiences when going through specific situations in her life. Stateanxiety is something that goes away after the situation that provokedit passes by. For example, if a car is about to hit a person while he iscrossing the road, he might experience state anxiety. However, thisfeeling of anxiety goes away once he realizes the car did not hit himand he is safe and can go back to his usual routine. Trait anxiety isspecific to a person’s personality and has been described in generalas type A (aggressive, high-stress personality) or type B (low-key,low-stress personality). Chronic anxiety disorders can lead tospecific phobias, social phobias, panic disorders, obsessive-compulsive disorder, or posttraumatic stress disorders.

Psychological distress refers to mental stressors that are notcongruous with good health. Feelings you may have when you aresick or facing medical situations such as surgery are examples ofdistress. In subjects of exercise studies, psychological distress isoften measured subjectively as a lack of well-being. Higher reportedlevels of well-being are usually associated with a higher quality oflife.

Self-esteem refers to feelings of self-worth and value that caninfluence mental health positively. For example, studies show thatpeople who begin an exercise program may experience higher self-esteem than nonexercisers. Further, more experienced exercisersmay maintain higher levels of self-esteem over time if they continueto exercise compared to people who stop exercising. However, ifadverse events such as injury or the adoption of addictive behaviors(e.g., compulsive running, exercise addiction, disordered eating)occur, self-esteem levels may drop or become inconsistent with goodmental health. Other addictive behaviors that are associated withlower levels of mental health are anorexia nervosa (limiting foodintake and becoming excessively lean), bulimia (bingeing andpurging), and muscle dysmorphia (a preoccupation withmuscularity).

Sleep disorders refer to alterations in the way one sleeps thataffect health and quality of life. Sleep disorders include insomnia(difficulty sleeping at night), sleep apnea (abnormal breathingpatterns while sleeping), restless legs syndrome (a sleepmovement disorder characterized by the urge to move one’s legswhile trying to fall asleep), narcolepsy (extreme sleepiness duringthe day), and many others.

RISK FACTORS ASSOCIATED WITH BRAIN HEALTHDISORDERSA full review of the risks associated with brain health disorders isbeyond the scope of this text; however, descriptions of some of therisk factors associated with common brain health are provided here.Many brain health disorders are associated with sedentary lifestylesor low levels of physical activity.

Numerous risk factors are associated with brain and mentaldisorders. Although each disorder has its own unique risk factors,several consistent themes appear across major mental healthdiagnoses.Modifiable Risk Factors for Brain and Mental Health Disorders

Physical inactivitySubstance abuse (including alcohol)Low self-esteemDistressNegative lifestyle behaviors

Nonmodifiable Risk Factors for Brain and Mental HealthDisorders

AgeSexHeredity (genetics)Undergoing traumatic experiences

Chronic medical conditions

Following are descriptions of the modifiable and nonmodifiablerisk factors for mental disorders:

• Physical inactivity. For some brain health conditions, a certainamount of physical activity appears to be very helpful, although toomuch exercise may aggravate existing mental health problems.

• Substance abuse. The abuse of any legal or illegal substance,particularly over a period of years, can lead to brain and mentalhealth disorders.

• Low self-esteem. Negative feelings of one’s capabilities, goals,accomplishments, place in the world, and relationships with otherscan have a major effect on mental health.

• Distress. Perceptions of the various stressors in life and theability to cope with them can positively or negatively affect thefunction of the central nervous system (CNS) and the adoption ofpositive or negative health behaviors.

• Negative lifestyle behaviors. Overcoming negative lifestylebehaviors by adopting positive ones can improve mental health.

• Age. Many brain health disorders (e.g., major depressivedisorder) are more commonly seen in younger adults; older adultsappear to be less affected, with the exception of those who becomechallenged to maintain their functional health.

• Sex. Women are at a higher risk for various brain and mentalhealth disorders (e.g., major depressive disorder) than men.

• Heredity (genetics). A family history of brain health disordersmay predispose a person to these conditions.

• Traumatic experiences and medical conditions. Traumaticexperiences and poor health conditions are known risk factors forbrain and mental disorders, most of which are nonmodifiable by theindividual. Previous suicidal thoughts are also a nonmodifiable riskfactor for future episodes. Age, self-esteem, genetics, and currenthealth status all affect how people cope with life stresses, how they

cope with the risk of suicidal thoughts, and how they respond tomedical treatments such as surgery and mental health therapy.

PHYSICAL ACTIVITY AND BRAIN HEALTHPrior to a discussion of the physiological mechanisms that mayexplain the observed relationship between physical activity andsome brain health disorders, it is helpful to conceptualize the breadthof work in the area. Perhaps more than any other health outcome inthis text, the bulk of the scientific work related to physical activity andbrain health has addressed physical activity as a possible treatmentfor the disorder. For example, does an exercise program improve thesense of well-being among people diagnosed with trait anxiety? Howmuch improvement might be expected? How long will theimprovement last? Does it depend on the dose (i.e., the amount) ofphysical activity? Can physical activity have an additive effect in anexisting treatment regimen—that is, can physical activity or exerciseimprove the effects of a standard treatment for a brain healthdisorder?

These questions do not address the issue of whether physicalactivity can prevent some brain health disorders from occurring at all.Clearly, preventing a disease is preferable to treating it once it hasbeen diagnosed (this is a central tenet of public health). However,less research has been conducted on the preventive role of physicalactivity in brain health disorders. Dunn and Jewell (2010) created auseful framework for conceptualizing existing (and future) studies ofphysical activity as a treatment modality for mental health disorders.This framework takes into account the three ways exercise andphysical activity may be used with people that already have a brainor mental health disorder: as a monotherapy (i.e., the sole treatmentunder investigation), as an augmentation therapy (i.e., to add toexisting treatments such as prescription drugs), or as an adjuncttherapy (i.e., having health benefits other than helping to treat thedisease). These three distinctive types are then placed into a 3-by-3table with the following lengths of effects: acute (short-term) effects

(the kind one might see with a standard laboratory-based exercisetraining study), continuation effects (moderate-term effects that mightbe expected when patients begin to exercise on their own), andmaintenance effects (longer-term effects that might signify theeffectiveness of the physical activity behavior in controlling thecondition under study).

The framework in figure 9.1 is particularly useful because it helpsus explore and categorize the physiological and behavioral effectsthat may be at work as mechanisms for any associations betweenphysical activity and brain or mental health outcomes. Acuteexercise-related adaptations are most likely to be initially apparent inshort-term training studies. The extent of physiological adaptations,as with other health outcomes, are likely dose dependent—that is,higher doses and intensities of physical activity result in greaterphysiological changes (see chapter 2). These adaptations shouldremain with a continued dose of exercise into the continuation andmaintenance periods, but behavioral changes should also beapparent as the exercise training theoretically evolves into aphysically active lifestyle.

Figure 9.1   Framework for the conceptualization of scientific research onphysical activity and brain health.Based on Dunn and Jewell (2010).

What physiological adaptations resulting from physical activitymay explain the association with some brain health disorders? Asnoted in previous chapters, even moderate-intensity physical activityresults in improvements in strength and muscular endurance, O2max, force, and power in most previously sedentary people. Theextent of these adaptations can be expected to correlate closely withthe dose of exercise: The higher the dose and the more intense thephysical activity, the greater the physiological response. Tounderstand the impact of these changes, we must also understandtheir effects on the brain and nervous system—the center of mostmental health disorders.

The physiological adaptations that result from physical activityhave been shown to improve cerebral capillary growth anddevelopment (also called angiogenesis), brain blood flow, andoxygenation. A popular hypothesis is that this increase in cerebralblood flow increases cerebral metabolism, and that this increasedcerebral activity (particularly in older adults) may be partially

responsible for a protective effect of physical activity against mentalhealth disorders (Deslandes et al. 2009). Other related hypothesesinclude the notion that exercise improves the regulation ofneurotransmitters (i.e., chemical substances that assist in thetransfer of nerve impulses across synapses), the growth andmaintenance of brain nerve cells, and the ability of nerves to conductimpulses across synapses.

Somewhat distally related to the physiologic adaptations are thebiomechanical improvements that result from physical activity.Biomechanically, people can expect to see improved economy orefficiency (i.e., reduced energy cost at a given workload) afteraerobic and musculoskeletal strengthening activities. Improvementsin balance, stability, mobility (flexibility and range of motion), andperipheral proprioception (i.e., sense of position and movement) canalso help people develop or maintain positive levels of self-esteemand well-being. The central hypothesis is that the development ofmotor skills allows people to participate in a greater variety ofphysical activity and exercise activities with more confidence, andthat these increases in self-efficacy can result in positive changes inmental health for some people.

Regular physical activity has measurable and substantialpositive effects on mental health.

How intense does physical activity need to be to have an effect onthese physiological markers of brain health? The answer certainlyvaries with the marker, but the best evidence from neurobiologystudies is that light physical activity (strolling, performing activities ofdaily living) is not enough to elicit the necessary physiologicalresponses. The physical activity must be ≥3.0 METs (i.e., moderateor vigorous intensity; see chapter 2) to generate the physiologicalstimulus necessary to promote mental health.

PHYSICAL ACTIVITY AND BRAIN COGNITIVE FUNCTIONPhysical activity may also affect brain cognitive function in peoplewithout any diagnosed brain health disorder. Many have wondered:Can physical activity make us smarter or help us remember thingsfor longer? Do people who are more physically active have bettercognitive function than similar, but inactive people? Do physicallyactive children do better in school than inactive children? Clearly,

these questions are associated with brain health becausecompromised brain cognitive function may be a subclinical precursorto more serious mental disorders.

Brain cognitive function outcomes that researchers haveinvestigated for an association with physical activity are shown infigure 9.2. This is not an exhaustive list, and studies have variedfrom single-bout exercise studies to short-term training studies. Thetopics highlighted in this figure are some of the most promising areasof current research in this field. The 2018 Physical ActivityGuidelines Advisory Committee Report concluded that there isstrong evidence demonstrating that short bouts of exercise have atransient benefit for cognition (i.e., it only lasts for a brief amount oftime after performing the exercise), which includes improvements inattention, memory, and processing speed. Studies have shown thatstronger effects occur among young children (prepuberty) andamong older adults. This is probably why some teachers or parentsreport that their student or child tends to be more attentive or to learnmore effectively just after having engaged in active play for a shortwhile. It is important to note that strong evidence currently exists ofthese positive effects on conditions for short bouts of exercise only(as compared to longer duration bouts), but it does not mean thatthat longer bouts of exercise would not be equally beneficial. This issimply an artifact of the way in which the experiments have beenperformed: Investigators asked study participants to perform shortbouts of exercise, then measured these aspects of cognitionimmediately after. More research examining the effects of sustainedand regular physical activity on cognitive outcomes is needed.

TESTING FOR BRAIN AND MENTAL HEALTHDISORDERSTests to evaluate, diagnose, and treat brain and mentalhealth disorders are typically conducted by physicians orresearchers with expertise in the area. Screening tests

(to identify cases to refer for more extensive diagnosticworkups) are often used as the first step in evaluatingmental health disorders. These tests range from self-administered questionnaires to in-person evaluations andobservation studies. An example of a simple mood disorderscreening assessment is the Profile of Mood States (POMS),which is a questionnaire-type instrument that assessesfluctuating mood states on key markers such as tension-anxiety, anger-hostility, fatigue, inertia, vigor-activity, and confusion-bewilderment. The POMS has beenused in a variety of clinical mental health settingsincluding those involving the relationships betweenphysical activity and exercise interventions orparticipation levels.

Cognitive function declines rapidly in older adults. Withpopulations in developed countries aging rapidly, questions of howphysical activity and exercise affect brain function become extremelyimportant as we seek to keep our parents and grandparentsfunctionally independent and mentally healthy for as long aspossible. There is strong evidence demonstrating that regularphysical activity helps prevent age-related cognitive decline,including preventing the development of dementia, and in particularAlzheimer’s disease. It is estimated that globally, 13% of all cases ofAlzheimer’s are a result of physical inactivity. In the United States,this estimate is 21%. Thus, regular participation in physical activitycould be an effective strategy to prevent numerous cases of thiscondition.

Figure 9.2   Brain function outcomes in youth and adults that have beeninvestigated for associations with physical activity and exercise.

PHYSICAL ACTIVITY, SLEEP, AND QUALITY OF LIFEQuality of life can be broadly defined as one’s satisfaction with life.Feeling satisfied with life—including feelings of accomplishment, lackof stress, and overall happiness—constitutes an importantcomponent of mental health. The broad term quality of life includesaspects related to physical and mental health as well as aspects thatgo beyond health, such as economic well-being. Figure 9.3 showsthe main concepts included under the umbrella of quality of life.Quality of life is known to be associated with several health and well-being outcomes. As such, many have wondered if leading aphysically active lifestyle helps us achieve better quality of life. Thereis strong evidence demonstrating that higher amounts of regularphysical activity are associated with positive perceptions of one’squality of life. For older adults in particular, physical activity cancontribute to improving health-related quality of life, in part, byhelping them maintain their physical function and independent

mobility, which in turn leads to better perceptions of their health-related quality of life (USDHHS, PAGAC 2018).

Recent years have also seen a substantial increase in the amountof research studies documenting the effects of physical activity onsleep disorders and sleep quality at large. There is sufficientevidence showing that physical activity, through acute bouts as wellas regular bouts of physical activity, can improve several sleepoutcomes among adults. In particular, acute bouts of physical activitycan help improve onset latency (how fast you are able to fall asleep),total sleep time, and how fast you can wake up in the morning.Meanwhile, being physically active on a regular basis can help inachieving a better quality sleep (USDHHS, PAGAC 2018).

Figure 9.3   Physical and mental health under the umbrella of quality oflife.From USDHHS, PAGAC (2018).

PHYSICAL ACTIVITY AND DEPRESSION AND MOOD DISORDERSOne may also wonder if physical activity can help prevent or managecertain mood-related conditions such as anxiety or clinicaldepression. More specifically, the evidence shows that anxiety isreduced when performing short, acute bouts of exercise. Thereduction in anxiety as a result of these acute bouts of activity occursin the period of time immediately after the exercise took place. Thismay be why you sometimes feel like going for a run or swimming afew laps when you are feeling overly anxious or stressed. In terms ofdepressive mood symptoms and clinical depression, it has beenfound that regular physical activity can help reduce the risk ofdeveloping depression. Now it is also known that physical activity

can help reduce the symptoms of depression among people thathave already been diagnosed with major depression.

PHYSICAL ACTIVITY GUIDELINES FOR BRAIN HEALTHScientific evidence supports the assertion that physical activitylowers the risk of (1) dementia including Alzheimer’s disease, (2)anxiety symptoms, (3) anxiety disorders, (4) depressive symptoms,(5) major depressive disorder, and (6) age-related decline incognitive function. There is moderate evidence suggesting thatphysical activity interventions may constitute an effective treatmentfor improving cognitive function among people with dementia,including Alzheimer’s disease, and other disorders that impaircognitive function, such as ADHD or Parkinson’s disease. Physicalactivity is recommended only as an adjunct therapy to othertreatment modalities (Blake 2012).

Figure 9.4   Physical activity and feelings of distress—prospective cohortstudies 1995-2007.Adapted from USDHHS, PAGAC (2008, G8-7).

Figure 9.4 is a summary of recent research on the dose-responserelationship between physical activity and exercise and feelings ofdistress. As shown, modest levels of physical activity (as comparedto lower levels of physical activity) are associated with significantlylower odds of distress, or higher odds of well-being. The data in thisfigure provide more evidence of the public health benefits of physicalactivity; the brain health benefits are not limited only to athletes andpeople who exercise at the highest levels.

How does participation in physical activity help maintain orimprove self-esteem?

Although scientific evidence through extensive research on thehealth benefits of physical activity and exercise on many physicalhealth outcomes exist, only since the 1980s have positiverelationships between physical activity and brain health begun toemerge in the literature. The development of new exercise sciencetechnologies and techniques along with the greater public healthemphasis on the management of brain and mental health disordersshould help us optimize physical activity and exercise interventionsfor those with mental health disorders.

SCIENTIFIC EVIDENCE

The 2018 PAGAC noted strong scientific evidence that physicalactivity has positive effects on four major components of brainhealth: cognitive function (including improved memory and attentionin prepubertal children and older adults, and risk reduction fordementia and Alzheimer’s), quality of life, mood disorders (includingdepression and anxiety), and sleep (including onset latency, totalsleeping time, wake time after sleep, and overall sleep quality)(USDHHS, PAGAC 2018).

Participation in regular physical activity and exercise can lowerthe risk for depression, distress and lack of well-being, and dementiaby 20 to 30%. Risk reduction for men and women appears to besimilar, and there is limited evidence that blacks, Hispanics, andwhite Caucasians benefit alike.

The dose of physical activity or exercise needed to reduce the riskof dementia (including Alzheimer’s), and to ameliorate mental healthdisorders (e.g., depression and distress) is three to five days perweek of 30- to 60-minute sessions of moderate-to-vigorous activities(moderate evidence). Scientific evidence of a dose-responserelationship between physical activity and exercise, lessenedanxiety, and improved sleep patterns is currently insufficient.

There is some scientific evidence that physical activity or exercisemay reduce the onset, progression, or adverse impact of centralnervous system (CNS) disorders such as multiple sclerosis andParkinson’s disease.

LEADER PROFILEJames (Jim) Sallis, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?I have always been interested in staying healthy—even as ateen, my pediatrician pronounced me fit. I would ask, “Isthere anything I should do to stay healthy?” He told me,“No, you’re fine.” I did not find that satisfactory. Todaythat would be close to malpractice, but things weredifferent in the early 1960s. For some reason, I had anearly recognition of the importance of preventingproblems.

When I was in graduate school studying psychology, myintention was to help people be mentally healthy. But atthat time the fields of behavioral medicine and healthpsychology were coming into existence, and those subjectareas resonated with my personal interest in stayinghealthy, so I decided to shift my focus to physicalhealth. I was fortunate to be accepted into a clinicalpsychology internship program at Brown University, whichwas a major center (then and now) for behavioral medicine.This was 1980, just after the publication of RalphPaffenbarger’s landmark papers on physical activity andhealth. Mass media covered the “fitness revolution,” and Idecided to become more active. One of my supervisors,Michael Follick, happened to mention to me, “There mightbe something to this exercise thing. It could be worthstudying.” For some reason that hit me like a bolt oflightning. It changed the course of my life because Idecided to apply for a postdoc with the Stanford Five-CityProject. Stanford University was (and is) a major centerfor physical activity research, with Ralph Paffenbarger,Bill Haskell, and Peter Wood being among the leaders.

Fortunately, I was able to secure a postdoc, and it setthe course for my career.

Did any one person have a major influence on your career?How?While I have had several influential mentors and learnedfrom many phenomenal and generous people, I want to singleout Bill Haskell. He helped me develop the ideas for myfirst papers on physical activity and guided me in theanalysis and writing of them. Bill and everyone else onthe team at Stanford were extremely gracious in letting mewrite several papers using Five-City Project data. I’msure it was Bill who recommended me to attend the veryfirst conference on physical activity and public health.It was organized by Ken Powell at the Centers for DiseaseControl and Prevention (CDC) in 1983. At the meeting inAtlanta, I met many leaders and soon-to-be leaders in thisnew field, creating an instant network with colleaguesthat grew into friendships. The meeting centered arounddiscussions of initial drafts of papers that attempted todefine this new field, and I was invited to coauthor two

of them. The resulting special issue in Public HealthReports in 1985 was a seminal publication that played alarge part in my transition from complete unknown to beingassociated with the leaders. So, I am grateful to Bill forgiving me that golden opportunity.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?My interests for the past 20 years have been performingresearch to understand how environments and policiesaffect physical activity for good or ill, and encouragingothers to study these big questions. It became obvious tome that some places are designed to make physical activitypleasant, fun, and safe, and some places are designed toachieve the opposite. In the United States, it seems likemuch more effort and money has been devoted to the latter.Thus, I believe we will not make an effect on physicalactivity until we invest more in excellent sidewalks andsafe bicycle facilities, reduce spending on roads, ensureevery neighborhood has parks and playgrounds designed forpeople to do multiple activities, provide physical

activity throughout the day at schools and early care andeducation settings, and change zoning laws to require morewalkable neighborhood designs.

In my training I was taught nothing about how tocommunicate research findings to the people who can usethem to improve practice and policy. Over the years I havelearned to write research briefs in lay language, developrelationships with decision makers in a wide range offields, present at practitioner conferences, findopportunities to meet directly with decision makersincluding elected officials, and work closely withadvocacy groups who have expertise in using research toinform practice and policy. Though these activities arerarely encouraged by universities, research translationactivities have been extremely rewarding.

Why do you do what you do?I work in physical activity because it is one of theworld’s most important public health problems, and it isreceiving too little attention and stimulating too littleaction to improve the situation. I want to use my time andenergy to research what I consider to be meaningful topicsand use the results to make as big a positive impact aspossible.

What are two key issues that must be addressed by 2030?The biggest problem in the field of physical activity andpublic health is the persistently low level of funding forresearch, programs, and policy advocacy. Physical activityis a low priority in every public agency I am aware of,resulting in inadequate funding. I do not have an answerabout how to increase funding by government, non-governmental organizations, foundations, or privatebusiness, so solving this problem will be the challengefor the next generation.

Creative research has generated many interventionstrategies with evidence of effectiveness, yet virtuallynone of these interventions are routinely implemented inthe United States or elsewhere. A big reason for thisfailure is the problem I just previously described. Wemust develop strategies for implementing evidence-basedintervention strategies, aimed at supporting individuals,improving environments, and changing policies, that reachall members of the population on an equitable basis.

GUIDELINESThe 2018 Physical Activity Guidelines Advisory Committee ScientificReport presents substantial evidence demonstrating that physicallyactive adults have a lower risk of depression and cognitive decline(i.e., decline in thinking, learning, and judgment skills, and reducedrisk of dementia including Alzheimer’s disease). Physical activity alsoimproves quality of sleep as well as quality of life, and acute bouts ofphysical activity have positive effects on anxiety. Among children andolder adults, acute bouts of physical activity positively contribute tobetter memory and attention. Brain health benefits have been foundin people who do aerobic activities or a combination of aerobic andmuscle-strengthening activities three to five days per week for 30 to60 minutes at a time.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

Brain and mental health conditions have been estimated toaffect 18.3% of American adults in any one year, and therelative increase in medical expenditures for mental disordersrose from $35.2 billion in 1996 (in 2006 U.S. dollars) to $57.5billion in 2006.Common brain health disorders include dementia,depression, bipolar or manic-depressive disorders, medicalconditions related to mood changes, substance-inducedmood disorders, anxiety, phobias, panic disorders, obsessive-compulsive disorder, posttraumatic stress disorders, feelingsof distress, CNS dysfunctions, and addictive behaviors.Common risk factors for brain health conditions includephysical inactivity, poor self-esteem, distress, drug abuse,

alcohol abuse, negative lifestyle behaviors, age, sex, suicidalthoughts, and medical treatments.Tests to detect brain health disorders are typically conductedby physicians (general practitioners) and specialists(psychiatrics and sleep study experts).Brain health benefits have been found in people who doaerobic activities or a combination of aerobic and muscle-strengthening activities three to five days per week for 30 to60 minutes at a time.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYAlzheimer’s Association. 2017. Alzheimer’s disease facts and

figures. Alzheimer’s and Dementia 13: 325-373.www.alz.org/documents_custom/2017-facts-and-figures.pdf.

American Psychiatric Association. 2013. Diagnostic and StatisticalManual of Mental Disorders: DSM-V, 5th ed. Washington, DC:American Psychiatric Association.

Blake, H. 2012. Physical Activity and Exercise in the Treatment ofDepression. Frontiers in Psychiatry 3: 106.

Deslandes A, Moraes H, Ferreira C, et al. 2009. Exercise andmental health: Many reasons to move. Neuropsychobiology 59:191-198.

Dunn AL, Jewell JS. 2010. The effect of exercise on mentalhealth. Current Sports Medicine Reports 9: 202-207.

DuPont RL, Rice DP, Miller LS, Shiraki SS, Rowland CR,Harwood HJ. 1996. Economic costs of anxiety disorders.Anxiety 2 (4): 167-172.

Greenberg P, Fournier AA, Sisitsky T, Pike CT, Kessler RC. 2015.The economic burden of adults with major depressive disorderin the United States (2005 and 2010). Journal of ClinicalPsychiatry 76 (2): 155-162.

Soni A. 2009. The five most costly conditions, 1996 and 2006:Estimates for the U.S. civilian noninstitutionalized population.Statistical brief #248. Rockville, MD: Agency for HealthcareResearch and Quality.www.meps.ahrq.gov/mepsweb/data_files/publications/st248/stat248.pdf. Accessed 23 September 2011.

U.S. Department of Health and Human Services, National Instituteof Mental Health. 2011. Statistics: Dysthymic Disorder AmongChildren.www.nimh.nih.gov/health/statistics/prevalence/dysthymic-disorder-among-children.shtml. Accessed 31 October 2018.

U.S. Department of Health and Human Services, National Instituteof Mental Health. 2016. Statistics: Mental Illness.www.nimh.nih.gov/health/statistics/mental-illness.shtml.Accessed 31 October 2018.

U.S. Department of Health and Human Services, National Instituteof Mental Health. 2017a. Statistics: Major Depression.www.nimh.nih.gov/health/statistics/major-depression.shtml.Accessed 31 October 2018.

U.S. Department of Health and Human Services, National Instituteof Mental Health. 2017b. Statistics: Persistent DepressiveDisorder (Dysthymic Disorder).www.nimh.nih.gov/health/statistics/persistent-depressive-disorder-dysthymic-disorder.shtml. Accessed 31 October 2018.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2018. 2018 Physical Activity

Guidelines Advisory Committee Scientific Report. Washington,DC: U.S. Department of Health and Human Services.https://health.gov/paguidelines/second-edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

World Health Organization. 2014. Mental Health: A State of Well-Being. www.who.int/features/factfiles/mental_health/en.Accessed 31 October 2018.

World Health Organization. 2018. International Classification ofDiseases. www.who.int/classifications/icd/en. Accessed 31October 2018.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.4.2, 2.1.1, 2.2.2, 2.3.3, 3.2.1, 3.2.2, 6.2.1, 6.4.1, 6.4.3

CHAPTER 10Health Risks of Exercise andPhysical Activity

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The primary health risks associated with exercise andphysical activity

»  Common musculoskeletal injuries associated with physicalactivity

»  Risk factors for exercise-related musculoskeletal injuries»  Exercise-related sudden cardiac death and the factors that

predict its occurrence

OPENING QUESTIONS»  What are the risk factors for exercise-related

musculoskeletal injuries?

»  Can these injuries be prevented?»  Does exercise cause sudden cardiac death or heart attacks?»  Do the benefits of physical activity and exercise outweigh

the risks?

»  Must someone consult a physician prior to beginning toexercise?

Throughout part II, the emphasis has been on the role physicalactivity plays in improving and promoting health. Physical activitylowers the risks of heart disease, some cancers, and diabetes;improves the musculoskeletal system; and prevents bone diseases.It improves quality of life and some mental health disorders. Thebenefits of physical activity are remarkable, particularly its ability tolower the risks of chronic diseases, and new research continues toteach us about these, and other, positive outcomes. But doesphysical activity also have a downside? Can participating in physicalactivity and exercise actually increase the risk of certain conditions?If so, do the benefits of being physically active outweigh the risks?

In public health, it is important to understand not only the healthbenefits of a certain behavior or intervention you may be promoting,but also the risks. Knowledge of a downside to any program iscritical to having a complete picture. Vaccination programs,environmental changes for cleaner air, educational programs for HIVprevention—all of these are examples of situations where programswith good intentions might have unintended risks to people andpopulations you are targeting. Understanding the risks as well as thebenefits of particular programs is practicing “responsible” publichealth.

Two primary unintended consequences (risks) of physical activitythat have been extensively studied are musculoskeletal injury andexertion-related sudden cardiac death. In this chapter, we reviewthese risks and put them in perspective in terms of the costs andbenefits of increasing physical activity.

MUSCULOSKELETAL INJURIESA physical activity–related musculoskeletal injury involves sometype of acute disorder in a bone, muscle, joint, or connective tissuethat is attributable to physical activity or exercise. Such injuries canoccur suddenly, such as an ankle sprain, or over a period ofexposure, such as a gradual pain in the shoulder of an electricianwho frequently works over his head installing circuits. Ligamenttears, sprains, strains, bone fractures, bruises, and joint dislocationsare common musculoskeletal injuries that can result from physicalactivity and exercise. Clearly, such injuries can occur withoutphysical activity (e.g., in a motor vehicle accident), but this chapteraddresses only those that result from some type of body movement.

A difficult problem when studying musculoskeletal injuries involvesthe definition of injury. What qualifies as an injury? You probablyknow what an injury means to you, but does your mother have thesame definition? How about a world-class sprinter or a heavymachine operator? Chances are that each person has a unique ideaof what an injury is. Many times it involves pain, loss of function, andan inability to work or socialize. Some people have a higherthreshold for pain than others do, so the same incident in two peoplemay be classified as an injury by one person and a “bump” by theother.

Severity is also an issue. How long does the pain or loss ofphysical function have to last before the incident is called an injury?Thirty minutes? Thirty days? Must a person see a physician or otherhealth care professional before an incident can be classified as aninjury? What if that person does not have health insurance? Surelysomeone without health insurance would be less likely to see a

doctor or health care professional for an injury than someone withinsurance and the same injury. This could result in a study or surveycounting one occurrence but not the other, simply because the lattercould not be “found.” Does someone have to be injured during anexercise session for the injury to be considered exercise related, ordoes an injury caused by cumulative exposure to exercise (e.g.,arthritis in the knee) also count as an exercise-related injury?

DEFINITION OF INJURYWhat type of exercise-related musculoskeletal injury wouldbe severe enough for you to report it on a survey? Wouldyou be able to remember a sore back after doing a day’sworth of gardening six months ago? Studies ofmusculoskeletal injury are limited because of the lack ofa standardized definition of what constitutes an injuryand the variability in the recall of study respondents.

The point is that, although the scientific literature is replete withstudies that have examined musculoskeletal injuries as related tophysical activity and exercise, a consistent definition has rarely beenused. This makes comparing studies nearly impossible. Studies thatrely on participants’ self-reports of “any injury” are not comparable tothose that require a doctor’s diagnosis prior to being classified as aninjury. What we know about the rates and risks of musculoskeletalinjuries due to physical activity and exercise is therefore limitedcompared to the wealth of information available on the healthbenefits.

What is the incidence of exercise-related injury? This simplequestion, unfortunately, does not have a simple answer because ofmany complications. First, as discussed, the definition of injury isvaried. Most people would count an event that was serious enoughto require a trip to an emergency room, but what about somethingless serious? Is an event that requires you to take a few days off

work, but not a trip to the emergency room, serious enough to beconsidered an injury? What about simply taking a few aspirin andself-treating for a few days? The main limitation to studies of physicalactivity and musculoskeletal injury is the use of inconsistent (andincomplete) definitions.

NUMERATOR MONSTERStudies of exercise-related injuries are particularly

prone to the numerator monster. This problem arises wheninjuries are counted, but the population at risk (thedenominator) is ignored. Epidemiologists rely on thenumber of cases (numerator) as well as the size of thepopulation at risk (denominator) to calculate prevalenceand incidence. If one or the other is not known, it isimpossible to compare types of activity and theirrespective risks for musculoskeletal injury. For example,if 100 walkers and 100 rugby players (both numerators)showed up at an emergency room one weekend for treatmentof exercise-related injuries, one might say that theactivities are equally dangerous. This assumption would beincorrect, however. There are many more walkers than thereare rugby players in a community. Without taking intoaccount the difference in size between the populations atrisk (the entire group of walkers and the entire group ofrugby players), one would miss the fact that rugby playersare much more likely to be injured than are walkers.Beware of the numerator monster.

Another complicating factor in determining the prevalence ofexercise-related injury is the fact that different types of physicalactivity have different participation rates and may result in differenttypes of injury. Low-impact and noncontact exercise activities andsports are likely less risky for musculoskeletal injury than are high-impact and contact sports. These differences make it somewhatmeaningless to discuss the prevalence of injuries in the samemanner we talk about the prevalence of diabetes or myocardial

infarction, both of which are single diagnoses. Similarly, we expectweight-bearing activities such as walking or running to be associatedwith injuries of the lower extremities more often than other parts ofthe body. Racket sports such as tennis and squash may be morelikely to result in injuries of the upper extremities (shoulders andarms) or the head (from being struck by a racket or a ball).

Finally, in the United States there are no routine surveys orsystems from which to generate a picture of exercise-related injuries.There have been periodic studies (Powell et al. 1998), studies ofcatastrophic injuries (Mueller and Cantu 1991), and studies thatfocus on numerators (Gotsch et al. 2002), but none of these havetracked these problems over time. This situation obviously makes itimpossible to truly understand the risks of physical activity, whichlimits public health professionals’ ability to give an accuraterisk/benefit assessment.

Although population-based exercise-related prevalence data arelimited, we do know some things about what might be expected tooccur for several types of physical activity in a defined time period.The data in table 10.1 are from a national survey of injury (Powell etal. 1998). By asking respondents what they were doing when theybecame injured, the investigators were able to compare varioustypes of common physical activities. Obviously, each of the reportedactivities is fairly safe; fewer than 3 people out of 100 were injured inany 30-day period. Outdoor bicycle riding appears to be the leastrisky activity in terms of musculoskeletal injury, and weightlifting wasthe riskiest.

Although these findings may appear to be intuitive, theyemphasize the need to quantify the risks of physical activity forapplication in the real world. For example, such information can bevery useful to a program manager who is beginning a community-based walking program for sedentary adults. After reviewing the datain table 10.1, the manager now knows that she might expect one ortwo people in her program to be injured during the walking programin a given month (30-day period). This is useful information for

program planning and evaluation. If she puts appropriate preventivestrategies in place and none of her participants become injured, shecan report that the participants in her program are injured lessfrequently than what one might expect given the literature.

Despite the problems in the scientific literature, we do know somethings about the causes and risk factors for physical activity–relatedmusculoskeletal injuries. These factors have been identified in thescientific literature from studies in epidemiology, biomechanics,physiology, and medicine. As with other health-related outcomes forphysical activity and exercise, risk factors can be convenientlyclassified as modifiable (i.e., things that can change or be changed)and nonmodifiable (i.e., things that typically can’t be changed or aredifficult to change).

Table 10.1   Percentage of Participants Reporting aMusculoskeletal Injury by Type of Physical Activity

Type of physical activity Percentage injured in 30 days

Aerobics or aerobic dance 1.4

Gardening or yard work 1.6

Bicycle riding (outdoors) 0.9

Walking for exercise 1.4

Weightlifting 2.4

Adapted from Powell et al. (1998).

Modifiable Risk Factors for Musculoskeletal Injuries

Amount and type of current physical activityCigarette smokingLow physical fitness levelImproper use of protective equipmentAdverse environmental conditions

Nonmodifiable Risk Factors for Musculoskeletal Injuries

Age

Sex (for some types of injury)History of injuryAmount of physical activity in the past (history)Anatomical factorsEnvironmental, or external, conditions

Following are descriptions of the modifiable and nonmodifiablerisk factors for musculoskeletal injury:

• Amount and type of current physical activity. The more physicalactivity a person performs, the higher the risk of musculoskeletalinjury associated with the activity. This finding has beendemonstrated repeatedly in the literature. Moreover, different typesof physical activity and exercise convey different risks. For example,contact sports are more likely to be related to injury than noncontactsports.

• Cigarette smoking. Although exercise and cigarette smokingwould appear contradictory behaviors, people whose occupationsdemand physical activity, such as construction workers andlandscapers, may also smoke. Cigarette smoking seems to increasethe risk of physical activity–related musculoskeletal injuries, possiblyas a result of vasoconstriction, which restricts the amount of oxygenbeing delivered to the muscles or connective tissues. The structureof the site and the availability of metabolic nutrients are then altered,and the hypothesis is that this alteration makes the muscle orconnective tissue more susceptible to injury.

• Low physical fitness level. People who have higher physicalfitness levels (measured as O2max) have been consistently shownto be at lower risk of musculoskeletal injury related to physicalactivity.

• Improper use of protective equipment. Bicycle helmets,protective padding for skateboarders, breakaway bases for baseballplayers, mouthguards for certain sports, shoes—all of these are

examples of protective equipment that, when properly used, canprevent musculoskeletal injuries associated with physical activity.

• Adverse environmental conditions. Environmental conditionscan be considered either nonmodifiable or modifiable. If conditionsare not conducive to physical activity or could increase the risk ofinjury during physical activity, venues can be changed, activities canbe rescheduled, or the type of physical activity can be modified (e.g.,going to the gym rather than playing basketball in the rain).

• Age. Changes in the musculoskeletal system that occur withaging result in older people being more likely to be injured thanyounger people doing the same activity.

• Sex. Women’s skeletal structure and sex hormones have beenhypothesized to increase their risk of lower extremity injury(specifically, to the anterior cruciate ligament in the knee) comparedto men doing the same activities.

• History of injury. A history of injury is one of the most consistentrisk factors for injury during physical activity reported in the literature.People who have been injured previously are more likely to beinjured in the future than those who have not. This is a strongrationale for efforts to prevent injuries from occurring in the firstplace.

• Amount of physical activity in the past (history). Much of whatwe know in the area of physical activity and musculoskeletal injurycomes from studies of military recruits who participate in basictraining involving substantial physical activity. Recruits who werephysically active prior to the training were less likely to be injuredduring the training. Again, this finding makes a powerful case forinjury prevention.

• Anatomical factors. Each human body is unique, and a person’sbiomechanical and anatomical characteristics may increase the riskof an (or exacerbate an existing) exercise-related musculoskeletalinjury. Among the many factors that have been hypothesized arevarus, or bowlegs (an abnormal inward angle of a bone); valgus, or

knock-knees (an abnormal outward angle of a bone); pes cavus (anabnormally high foot arch); and pes planovalgus (flat feet). Manyanatomical problems can be reversed through medical intervention.

• Environmental, or external, conditions. A frequently overlookedrisk factor for exercise-related musculoskeletal injuries isenvironmental conditions. Traffic, damaged or wet playing fields orcourts, and broken sidewalks are all examples of environmental, orexternal, conditions that could increase the risk of a musculoskeletalinjury associated with physical activity.

Figure 10.1   Rates of exercise-related musculoskeletal injuries for men andwomen.Adapted from Hootman et al. (2001).

KINESIOLOGY AND MUSCULOSKELETAL INJURIESThe scientific literature fairly consistently reports a dose-responserelationship between the risk of musculoskeletal injury and theoverall dose (or volume) of physical activity. The results come fromstudies of runners and walkers (Macera et al. 1989) and militaryrecruits (Almeida et al. 1999). Quite simply, the more physical activityyou do, the higher your risk of musculoskeletal injury. The dose of

physical activity, as we learned in chapter 2, is related to frequency,intensity, and duration.

Physical activity can increase the risk of adverse events suchas musculoskeletal injuries or sudden cardiac death. Do thebenefits of participating in regular physical activity outweighthe risks?

The type of physical activity can also influence the risk of injury.Low-impact weight-bearing activities (e.g., walking) or non-weight-bearing activities (e.g., swimming laps, cycling) are thought to beassociated with the fewest musculoskeletal injuries related tophysical activity. In contrast, running and sport participation(particularly contact sports) may carry a much higher risk of injury.This difference is thought to operate through greater stresses onconnective tissue and higher-impact forces on bones and joints. In astudy conducted by Hootman and colleagues in 2001, people whoreported participating in sports had nearly twice the risk of activity-related injury compared to nonexercisers (see figure 10.1).

Among people who play sports, collision sports (ice hockey,American football, rugby) or contact sports (basketball, soccer) carrya higher risk of injury than limited-contact sports (baseball) and

noncontact sports (cycling, racewalking). These results come frommultiple surveys, each with its own definition of injury.

An interesting line of research has emerged regarding physicalactivity and risk of musculoskeletal injuries. Although higher doses ofphysical activity appear to be related to a higher acute risk of injuryassociated with that activity, could it be that the overall risk of beinginjured (both exercise- and nonexercise-related musculoskeletalinjuries) shows an overall decrease with increased physical activity?This would seem an important overall health question, particularly forolder adults who are susceptible to injury as a result of falls.

Carlson and colleagues (2006) examined this question in a studyof more than 96,000 adults in the United States. Survey respondentswere asked about their physical activity behaviors and classified intothree groups: meeting physical activity guidelines (at the time of thestudy, 30 minutes of moderate-intensity aerobic physical activity onfive or more days per week), insufficiently physically active (someactivity reported, but not meeting the guidelines), and inactive (nophysical activity reported). The authors studied injury patternsoccurring acutely during physical activity and in times not associatedwith physical activity across the three groups. Key results are shownin figure 10.2.

The risk of exercise-related musculoskeletal injury was elevatedduring physical activity in both groups (20% in those who wereinsufficiently active and 53% in those who were meeting physicalactivity guidelines). This was expected because more active peopleseem to be at higher risk for injury during physical activity. Thesurprising finding came in the overall injury risk (combining exercise-related and nonexercise-related injuries). People who were active (–3%) or somewhat active (–12%) were actually at a lower overall riskof injury compared to inactive people. The finding was particularlystriking for injuries not due to physical activity. These results seem tosuggest that, although the risk of exercise-related musculoskeletalinjuries is elevated during exercise, people who are habitually activehave a lower overall risk of any injury.

Figure 10.2   Association of habitual physical activity with risk of injuryduring physical activity and overall. Risk of injury is relative to inactivesubjects.Adapted from Carlson et al. (2006).

Many people believe that stretching muscles prevents exercise-related musculoskeletal injuries. Stretching, either before or after anexercise session, feels good and increases flexibility around thejoints. The theory is that this increase in flexibility and additionalblood flow to the areas being stretched put muscles, joints, andconnective tissues at a lower risk of strain or stress andsubsequently a lower risk of injury. Although this is an attractivehypothesis, the results of numerous studies have failed to confirmthis finding. In fact, the scientific literature is now consistent with theconclusion that stretching before or after an exercise session doesnot decrease the risk of injury. Flexibility is obviously an importantcomponent of physical fitness but it does not seem to result in alower risk of exercise-related musculoskeletal injuries.

SUDDEN ADVERSE CARDIAC EVENTS

The images are all too familiar: A recreational runner dies during aweekend 10K race. A homeowner shoveling snow from his drivewayafter a winter storm falls to the ground and dies. A young, seeminglyfit and healthy basketball player dies during a game. Sudden cardiacdeath is an unexpected death due to a dysfunction of the heart,usually within one hour of the onset of symptoms. Physical activityand exercise, particularly when performed at a vigorous intensity, areassociated with a higher risk of a sudden adverse cardiac event(i.e., cardiac arrest, cardiac death), when compared to times of noactivity or light- or moderate-intensity activity.

When does the highest risk of a cardiac event associated withexercise occur?

Many types of cardiac disorders can place people at an increasedrisk of sudden cardiac death. As reviewed in chapter 5, the risk ofatherosclerotic heart disease is substantially lower among peoplewho are or who become physically active. This lower risk is primarilyseen in men and women older than 30. Other disorders, includinghypertrophic cardiomyopathy (a genetic disorder characterized by an

overly thick wall in the left ventricle), electrical conduction disorders,and abnormalities in the cardiac arteries, are all important conditionsthat place people at risk of sudden cardiac death, particularly duringphysical activity and exercise. Such conditions are mostly inherited.Although regular participation in moderate-intensity physical activitycan lower the risk of chronic diseases and conditions such asobesity, atherosclerotic heart disease, diabetes, colon and breastcancer, and osteoporosis, people with conditions that increase therisk of sudden cardiac death should avoid vigorous-intensity physicalactivity. Moreover, people with a family history of these conditionsshould be examined and monitored by a physician.

Vigorous-intensity physical activity has also been shown to be atrigger for sudden cardiac death due to atherosclerotic heart disease.This process, thought to be a result of a fibrous plaque that rupturesinside a coronary artery and essentially cuts off the blood flow to aportion of the heart, can be a very dangerous situation. Evidence ofthis process comes from studies of people who have had suddenadverse cardiac events.

OVERLOAD, ADAPTATION, AND SPECIFICITYThe fundamental principles of overload, adaptation, andspecificity outlined in chapter 2 are particularlyrelevant when discussing the prevention of exercise-related musculoskeletal injuries. Overload, or exercisingbeyond usual levels, stimulates bones, muscles, joints,and connective tissue to increase their function. If thisoverload is sustained (or repeated frequently), the bodyadapts to a new normal based on the physical training.Laboratory-based studies and animal studies have taught usthat bones, muscles, ligaments, and tendons all adapt toincreased physical activity (i.e., they get stronger withmore physical activity, or overload), and that targetedactivity (e.g., focusing on the lower limbs) will likelyprevent injuries in that area. However, large overloadswith little or no time to adapt may increase the risk ofexercise-related injury (particularly traumatic injury),

and little or no overload does not prompt any adaption,and may also increase the risk of injury.

Mittleman and colleagues (1993) studied more than 1,200 menand women who had survived a myocardial infarction (i.e., a suddenloss of oxygen to the heart muscle). They interviewed all studysubjects and determined what they were doing immediately prior toor during the cardiac event and classified them based on whetherthey were physically active. Figure 10.3 illustrates the main results.

Figure 10.3   Relative risk of onset of myocardial infarction by hours ofexertion prior to an event.Adapted from Mittleman et al. (1993).

As figure 10.3 shows, the risk of a myocardial infarction related toexertion is largely limited to the first hour after the activity. During thistime, men and women in this study were nearly six times more likelyto develop a myocardial infarction. After the first hour, the risk was

negligible. Although these events were nonfatal, this evidence iscompelling and clearly suggests that the period of highest risk for anadverse cardiac event is during or within the first hour after cessationof exercise.

If vigorous-intensity physical activity increases the risk of adversecardiac events, why is it recommended? Why promote physicalactivity if it increases the risk of death or nonfatal heart attacks? Theanswer to this question lies in the big picture. Multiple studies sincethe 1980s have shown that, although vigorous-intensity physicalactivity acutely increases the risk of sudden cardiac death, theoverall risk of sudden cardiac death (throughout the rest of the day)is actually lower among people who are habitually physically active.That is, the cardiac risk that occurs as a result of an acute bout ofphysical activity is outweighed by an overall lower risk of suddendeath in active people compared to inactive people. This concept isperhaps best illustrated by figure 10.4.

Figure 10.4   Risk of cardiac arrest during vigorous-intensity physicalactivity and at rest by usual level of physical activity.Reprinted from USDHHS, PAGAC (2008).

Over a 24-hour period, the risk of cardiac arrest for someone whoremains inactive (thin unbroken line in figure 10.4) is far higher thanthe average risk for someone who is habitually active (dashed line).The risk for cardiac arrest is far higher for that active person duringor immediately after the period of physical activity (spike), butoverall, the active person is at a much lower risk (even when this

period of activity is taken into account) than the inactive (sedentary)person. This situation is similar to that reviewed earlier formusculoskeletal injuries. The overall benefit to being physicallyactive far outweighs the short-term acute risk of adverse events dueto physical activity.

LEADER PROFILEMichael Pratt, MD, MSPE, MPH

Why and how did you get into the field of PhysicalActivity and Public Health?By repeatedly being in the right place at the right time.I was a track and cross country runner at UC Davis andinterested in the science behind running and performance.Those experiences led me to graduate school in exercisescience in the Kinesiology Department at the University ofWashington where, among other things, I ran rats on atreadmill and studied their mitochondria. I came to theconclusion that I needed further education, and that Ipreferred my study subjects alive rather than in ablender, thus I opted for an MD as opposed to a PhD inphysiology. While I was in med school at the University ofWashington, Ken Powell organized a seminal workshop onphysical activity and public health at the Center forDisease Control (as the CDC was know as at that time). The

workshop proceedings were published in Public HealthReports (1985) and created a framework for understanding

physical activity as a public health issue. This wasamazing—it was actually possible to combine the two areasI was most interested in: epidemiology and physicalactivity!

Did any one person have a major influence on your career?How?Upon reflection the answer here is two people. Theaforementioned Ken Powell is one major influence, as Ieventually found my way to the CDC to be mentored by Dr.Powell. As you might expect of somebody who defined a newfield within public health, Ken is visionary, intelligent,and a master of the craft of epidemiology, but he is alsohumble and simply a wonderful person. Thanks to Ken, Ibecame a physical activity and public health guy, but Iwas predestined to be a scientist of some sort. My fatherwas a microbiology and genetics professor at theUniversity of Wisconsin and UC Davis. I spent many hoursas a little kid hanging out in my dad’s lab surrounded bypipettes, petri plates, postdocs, and the whole academicmilieu. Discovery, collaboration, teaching—if it was theright thing for my Dad it must be what I was meant to do.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?I always describe myself as a generalist in a specializedarea. This is par for the course for many physicians inpublic health. We need to be pretty good at a variety ofthings because all those PhDs are so much smarter than usin their specialty areas. So I have done somesurveillance, physical activity (PA) counseling research,community interventions, environment and PA, economics,and eventually what I currently focus on, global PApolicy. Translating research into practice and policy isnever easy. It is facilitated by partnering from the startwith communities, governments, and internationalorganizations, such as WHO, and being very focused on afew factors that are generally undervalued in biomedicalresearch: external validity, feasibility, pragmatism.

Why do you do what you do?The same reason as pretty much everybody in public health—to try to make the world a better place.

What are two key issues that must be addressed by 2030?

1. Equity. Physical activity is good for everyone, butthe distribution of these benefits across society and

across the globe is far from uniform. From basic

research to public policy—we need to close these gaps.

2. Harnessing technology and data science for physicalactivity surveillance. We have done pretty well using

self-report to guide our work on physical activity and

health, but the tools now exist to be much more

precise. However, there are important and exciting

challenges around conceptual differences between self-

report and objective measures, sampling, continuous

data collection, data synthesis, scoring, and

interpretation of this information to enhance our

understanding of basic health relationships and guide

policy.

Must someone who is sedentary consult a physician or otherhealth care provider prior to beginning a physical activity program?This message has been around for many years and always seemslike a good idea. The reality, however, is that this creates asignificant barrier for many people who can use it as an excuse notto exercise.

According to the 2008 U.S. Physical Activity Guidelines AdvisoryCommittee (U.S. Department of Health and Human Services[USDHHS], Physical Activity Guidelines Advisory Committee[PAGAC] 2008), there is no evidence that people who visit aphysician or other health care provider prior to starting an exerciseprogram are any safer than those who do not. Following thefundamental principles of exercise physiology (overload, adaptation,and specificity) by making small, comfortable increases in physicalactivity over one’s usual behavior should minimize any acute cardiacor musculoskeletal risks associated with physical activity. In these

cases, consultation with a health care provider is not necessary.People who plan to make large, high-intensity increases in physicalactivity without allowing for any adaptation time, who have chronicconditions that may increase acute risk, or who have generalconcerns about exercising should consult with a health care provider.Someone who is sedentary and wants to begin exercising with awalking program of light to moderate intensity would not need such aconsultation.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

Musculoskeletal injuries and sudden adverse cardiac eventsare two important risks of physical activity participation.The exercise physiology principles of overload, adaptation,and specificity are important considerations in understandingthe risks of exercise and physical activity.The definition of musculoskeletal injury is an importantconsideration for interpreting the literature.Studies of musculoskeletal injury prevalence and incidencemust take the population at risk into account.The acute risks of injury and adverse cardiac events areelevated during or immediately after a physical activity bout.The overall risk of both conditions is lower among people whoare habitually physically active.Consultation with a medical care provider may be necessaryfor some people, but for the majority of sedentary people whowish to become active at a moderate level, suchrequirements should not be a barrier to participation.The benefits of physical activity participation far outweigh therisks.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYAlmeida SA, Williams KM, Shaffer RA, Brodine SK. 1999.

Epidemiological patterns of musculoskeletal injuries andphysical training. Medicine & Science in Sports & Exercise 31:1176-1182.

Carlson SM, Hootman JM, Powell KE, Macera CA, Heath GW,Gilchrist J, Kimsey CD Jr, Kohl HW III. 2006. Self-reportedinjury and physical activity levels: United States 2000-2002.Annals of Epidemiology 16: 712-719.

Gotsch K, Annest JL, Holmgren P, Gilchrist J. 2002. Nonfatalsports- and recreation-related injuries treated in emergencydepartments—United States, July 2000–June 2001. Morbidityand Mortality Weekly Report 51: 736-740.

Hootman JM, Macera CA, Ainsworth BE, Martin M, Addy CL, BlairSN. 2001. Association among physical activity level,cardiorespiratory fitness and risk of musculoskeletal injury.American Journal of Epidemiology 154: 251-258.

Macera CA, Pate RR, Powell KE, Jackson KL, Kendrick JS,Craven TE. 1989. Predicting lower-extremity injuries amonghabitual runners. Archives of Internal Medicine 149: 2565-2568.

Mittleman MA, Maclure M, Tofler GH, Sherwood JB, Goldberg RJ,Muller JE. 1993. Triggering of acute myocardial infarction byheavy physical exertion: Protection against triggering by regularexertion. New England Journal of Medicine 329: 1677-1683.

Mueller FO, Cantu RC. 1991. The annual survey of catastrophicfootball injuries: 1977-1988. Exercise and Sport SciencesReviews 12: 261-312.

Powell KE, Heath GW, Kresnow MJ, Sacks JJ, Branche CM.1998. Injury rates from walking, gardening, weightlifting,outdoor bicycling and aerobics. Medicine & Science in Sports &Exercise 30: 1246-1249.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2008. Physical ActivityGuidelines Advisory Committee Report, 2008. Washington, DC:U.S. Department of Health and Human Services.https://health.gov/paguidelines/2008/report/pdf/CommitteeReport.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

2.1.1, 2.2.1, 2.2.2, 5.2.5, 6.1.1, 6.1.3, 6.1.4, 6.1.5,6.2.1, 6.3.1, 6.3.6, 6.4.1, 6.4.4

PART IIIStrategies for EffectivePhysical Activity Promotion

CHAPTER 11Informational Approaches forPromoting Physical Activity

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The Guide to Community Preventive Services Task Forcerecommendations for physical activity promotion

»  The rationale for promoting physical activity interventionsthrough informational approaches

»  Considerations for using community-wide campaigns

»  Considerations for using mass media campaigns»  Characteristics of effective health education curricula»  Considerations for using classroom-based health

education programs

OPENING QUESTIONS»  Have you ever tried to help someone increase physical

activity levels or begin an exercise program by providinginformation on the health benefits of physical activity?

»  Did it work? How successful were you over the short term andlong term?

»  Which types of informational approaches actually increasephysical activity?

»  What are the components of these approaches?

Parts I and II of this text focused on defining the field of physicalactivity and public health and on outlining the myriad health benefitsto being physically active. In this part of the text we introducestrategies that have been proven to help people increase or maintaintheir physical activity levels. The information in this part, derived frombehavioral, population, and environmental research, separatespublic health research from other forms of research. In most cases,results from public health research are translated into practice toimprove the health of populations and individuals. Public healthresearch generates new knowledge, as do virtually all other types ofresearch. Fundamentally, though, applying the results of publichealth research to a particular health problem is a critical step.

The best resource for translating public health research intopractice in the United States is The Guide to Community PreventiveServices, or the Community Guide. The Community Guide containsguidance on health improvement strategies for numerous topics,including physical activity. Each recommended strategy in the

Community Guide is based on a rigorous review of availablescientific evidence—the recommended strategies for healthpromotion and disease prevention that are found in the CommunityGuide, for example, have been thoroughly reviewed and scientificallytested.

The Physical Activity sections of the Community Guide include thefollowing review areas, which are discussed here and in more detailin chapters 12 through 14:

School-based methods (chapter 12)Behavioral and social methods (chapter 13)Environmental and policy approaches (chapter 14)

UNDERSTANDING THE COMMUNITY GUIDEThe Community Guide is an ever-expanding resource forrecommendations on evidence-based interventions to improve publichealth. The Task Force on Community Preventive Services (TaskForce) was established by the U.S. Department of Health andHuman Services (USDHHS) in 1996 to clarify which community-based health promotion and disease prevention interventions work,and which do not. The U.S. Centers for Disease Control andPrevention (CDC) is the USDHHS agency that provides the TaskForce with technical and administrative support. Our review is drawnfrom the recommendations in the Community Guide, but werecommend that you also visit the Community Guide website andread the information contained there as well(www.thecommunityguide.org).

The information in the Community Guide provides support for avariety of activities related to public health, such as the following:

Policies. Provides an understanding of concepts and researchthat can help in the development of more effective legislationand organizational policies.

Research. Identifies research gaps, research priorities, andhigh-quality evidence-based studies.Programs. Helps with program planning and health promotionservices.Education. Disseminates knowledge of effective public healthstrategies.Funding. Provides background information for creating grantproposals and gaining access to funding streams.General. Helps determine what works and how to make wiseuse of resources, and builds community support.

EVIDENCE-BASED PUBLIC HEALTHThe Community Guide offers practitioners and decisionmakers strategies for preventing or addressing healthproblems. To save from having to continually try variousstrategies that may or may not be successful, theCommunity Guide provides a one-stop shop for peopleinterested in translating research into programs that havea better chance of succeeding. The Community Guide savestime and money and helps keep public health programdevelopers from having to reinvent the wheel. When indoubt, go with the evidence-based strategy.

When reviewing research from physical activity programs, theTask Force takes into account the types of activities targeted, thebreadth of their impact, how programs are delivered, the targetpopulation, and the type of setting in which the programs aredelivered. The Task Force also seeks the answers to the followingquestions about specific physical activity interventions:

Does it work?If it does work, how well?For whom does it work?

Under what circumstances is it appropriate?What does it cost?Does it provide value?Are there barriers to use?Are there any risks?Are there any unanticipated outcomes?

Reprinted from the Community Guide.

Although a review of all the criteria the Community Guide uses tojudge a study or studies is beyond the scope of this text, suffice it tosay that they are very stringent. Only the best studies, with adequatenumbers of participants and methods, are evaluated. Once all of thestudies in a particular area are assessed, the Task Forcerecommendations about specific physical activity programs arecategorized into the following three broad groupings:

Recommended: Strong or sufficient evidence that theintervention or program is effective.Recommended against: Strong or sufficient evidence that theintervention or program is not effective, or is harmful.Insufficient evidence: The available studies do not providesufficient evidence to determine whether the intervention iseffective.

Classifying a program as having insufficient evidence can meanone of several possible things. First, additional research may beneeded to determine whether the intervention is effective; thenumber of studies may be insufficient to draw any firm conclusions;or the studies may lack sufficient quality. Second, the studies may allbe of sufficient quality and size, but they may present inconsistent orcontradictory findings, or both. Finally, the studies may be consistent,but the results may not be of sufficient size or intensity to confidentlydescribe an effect—that is, the statistical significance of the findings

may not support the results. In this case insufficient evidence doesnot mean that the intervention or program does not work.

RATIONALE FOR INFORMATIONAL APPROACHESIf knowledge is power, does more knowledge about the healthbenefits of physical activity translate into more power to changebehavior among people who are physically inactive? Informationalapproaches may be designed to increase leisure, occupation,transportation, or at-home physical activities. These approaches arebased on the idea that when people are taught about the healthbenefits of a certain behavior (such as physical activity), they willchange their behavior for the better. Obviously, we all know that wesometimes choose to behave in ways that are not good for us;however, informational approaches can increase our knowledge andreinforce our desire to change when we are motivated to make achange.

In general, informational approaches to physical activity promotionmay change behaviors through several pathways. First, an increasein knowledge about the health benefits and risks of physical activity(see chapters 5 through 10) may be sufficient for behavior change insome people. For example, a person with a substantial family historyof heart disease may be more likely to become physically active ifshe learns that activity may lower her risk due to her geneticmakeup.

Second, informational approaches may encourage people to bephysically active by extending their knowledge about where and howto be active in their communities. For example, building a bicycle trailmay not be enough to encourage physical activity; however,providing information about the trail, its entry and exit points, safetyfeatures, and other characteristics may increase the use of the trailfor physical activity.

Third, informational strategies may help people identify thepersonal and environmental reasons they are physically inactive andhelp them overcome them. Finally, informational approaches can let

people know when opportunities for physical activity are happeningin their communities, at their worksites, or in other settings. Thisknowledge can then be converted to action. For example, when aneighborhood walk or other event is scheduled, informationalapproaches can increase awareness, registration, and participationin the event, thereby increasing physical activity.

TIMETime—no one has enough of it; everyone is busy. Lack oftime is consistently cited in surveys and studies as thenumber one reason people are not physically active.Although it may be true that people make time for thingsthat are important to them, informational approaches tophysical activity participation can help people identifywhy they believe they don’t have time to be physicallyactive and how they can rearrange their schedules to makeroom for physical activity.

Informational approaches for promoting physical activity that havebeen evaluated by the Task Force include community-widecampaigns, mass media campaigns, and classroom-based healtheducation curricula for youth that focus on providing information andskills development. The remainder of this chapter reviews each ofthese informational approaches, provides an assessment of theeffectiveness of each in promoting physical activity, and providesexamples of success.

COMMUNITY-WIDE CAMPAIGNSHave you ever seen a billboard in your community that urges you toexercise more, or a late-night television advertisement or intranetsite at your workplace or university that reminds you to be physicallyactive? Have you ever received an email reminding you of the healthbenefits and importance of being physically active? These are allexamples of informational approaches to promoting physical activity.

Unfortunately, these “single-stream” techniques rarely, if ever,succeed in getting people to become more active.

When single-stream techniques are combined into multipleintensive strategies targeted toward increasing physical activity,however, they can be successful. One of the recommendedstrategies for increasing physical activity via informationalapproaches is a community-wide campaign. These campaigns relyheavily on communication to change behavior through increasedknowledge.

Community-wide informational campaigns for physical activitypromotion have three defining characteristics. First, they includemany community sectors. That is, they are not limited to messagesfrom the local health department, parks and recreation department,hospital, or mayor’s office. Successful programs create consistentmessages and program identification (e.g., logos, tag lines) acrossthose sectors.

Second, community-wide informational campaigns frequentlyinclude very visible, broadly targeted strategies. To succeed, theycannot be limited to one-way communication methods, such astelevision advertisements or billboards by the side of the road.Rather, they should be incorporated into other health-related events,such as health fairs, cancer screening events, and other activitieswhere people may gather. Moreover, social media strategies (mobileand desktop) can supplement one-way communication strategiesand make them interactive.

Finally, community-wide informational campaigns can besuccessful if they are included in other activities that focus onphysical activity–related health issues. For example, a heart diseaseprevention program at a large worksite may include physical activitypromotion information. Such programs have been shown to increasephysical activity in the targeted population.

Community-wide informational campaigns often include television,radio, newspaper, and other media to raise program awareness,disseminate physical activity health messages, and reinforce

behavior change. Targeted mailings and communications from keyinfluencers such as places of worship and community centers thatsupport the informational campaign can also be very effective.

Community-wide campaigns, if done correctly, have been shown tobe effective strategies to promote physical activity. Let’sMove! is former First Lady Michelle Obama’s initiative toreduce childhood obesity.Reprinted from Let’s Move Outside: America’s move to Raise a healthier Generation ofKids.

Taken together, existing studies in this area show that community-wide informational campaigns to increase physical activity do thefollowing:

Increase the percentage of people who report being physicallyactive (at least in the short term) by an average of 4.2%.Increase caloric expenditure by an average of 16.3%.Increase multiple types of physical activity.Increase participants’ knowledge about exercise and physicalactivity.Increase participants’ intentions to be physically active (eventhough they may not actually be carrying through on thoseintentions).

Reduce risk factors for cardiovascular disease that are relatedto physical inactivity.

Of note, however, is that these same studies reported equivocalfindings on body weight. Some studies showed weight loss, butothers showed no change or even slight weight gains. Thus, it isclearly possible to increase physical activity without weight loss.

Community-wide campaigns for physical activity promotion aretypically not easy to organize. They require substantial planning,coordination, and evaluation efforts to determine effectiveness.Partnerships must be developed, and partners need to be countedon to assist in the campaign. An underfunded and underplannedcampaign will underperform.

MASS MEDIA CAMPAIGNSMass media campaigns are physical activity promotion programsthat rely on messaging efforts to change physical activity behaviorthrough changes in knowledge, beliefs, and attitudes. The exposureto mass media campaigns can be measured in a variety of ways, butis usually summarized as the number of times an average targetgroup member will view, hear, or see the message. Such campaignscan (and probably should) be part of a community-wide informationalcampaign, but do not constitute a community-wide effort on theirown. Following are characteristics of mass media campaigns forphysical activity promotion:

Are typically designed as large-scale efforts to transmitmessages about physical activity to large and nonspecificaudiences; anyone is considered a target.Are designed to increase physical activity by increasingknowledge and changing attitudes and beliefs.Use communication media exclusively, including newspapers,TV, radio, and billboards.Can rely on a single communications channel (e.g., billboards)or a combination of channels.

The Task Force found insufficient evidence to recommend massmedia strategies for physical activity promotion. These kinds ofprograms can be very expensive and difficult to carry out, and themoney spent may well be wasted. Many reasons may explain thislack of effect, including poorly produced or poorly placed mediaproducts and the lack of a defined target audience.

Although the Community Guide does not recommend mass mediaapproaches for physical activity promotion because of insufficientevidence, research evidence has emerged that has led someauthors to label the strategy as promising (Heath 2009).

Why don’t mass media campaigns seem to work for physicalactivity promotion? Many communities and countries have used suchcampaigns, yet changes in behavior across a target audience havebeen difficult to demonstrate. Bauman and Chau (2009) reviewedmass media campaigns and provided some ideas about why theywere not successful. First, the campaigns may not have hadconsistent, comprehensive messaging strategies. For example,some campaigns focused on increasing exercise behaviors, whereasothers focused more broadly on physical activity of all kinds.Alternatively, some focused on sport participation, whereas othersfocused on lifestyle-related physical activity.

Second, the target behavior was inconsistent. Urging people totake a walk is not the same as urging them to meet therecommendation of 150 minutes per week of moderate-intensityphysical activity. Mass media approaches may work for one type ofactivity outcome, but not for another.

Third, the campaign may not have been sequenced correctly.Sequencing here means that the messages are built on one anotherin a logical fashion to encourage behavior change.

Fourth, resources may have been insufficient to reach deeply intothe targeted audience or to evaluate the effectiveness of thecampaign properly. As with community-wide campaigns,underfunded efforts are likely to underperform.

Finally, to have a reasonable chance at success, mass mediacampaigns for physical activity promotion cannot be used in isolation(Bauman and Chau 2009). They must be implemented as part ofcomprehensive programming with messaging supporting thepolicies, programs, and environment of the specific physical activityintervention. In other words, mass media campaigns that areimplemented without supporting actions, policies, or places foractivity are not effective.

Clearly, television, radio, and print media are giving way toelectronic, web-based, and social media. Can these new media beuseful in promoting physical activity, and should they be consideredmass media strategies? The question is a bit tricky becauseelectronic media allow messages to be tailored to (and by) thepeople being targeted, rather than a more traditional one-size-fits-allapproach that has characterized mass media strategies to date.Campaign developers can tailor the type, frequency, andappearance of the message to the characteristics of the receiver.This is very different from the “blunt instrument” approach oftraditional mass media. Bauman and Chau (2009) evaluated newmedia physical activity interventions (primarily web-based) andconcluded that these new methods of social marketing can bedeveloped and tailored to individuals to encourage behavioralchange, but more research is clearly needed in this area.

CASE STUDY

ACTIVE AUSTRALIACan the physical activity levels of an entire state beimproved? Active Australia (Bauman et al. 2001) is aperfect example of a community-wide campaign that was

able to show that they could. In a two-month period in1998, a statewide campaign was initiated and conductedby the New South Wales (Australia) state healthdepartment. The campaign sought to increase physicalactivity levels in adults 25 to 60 years of age.Informational strategies used in the project includedpaid television and print advertising, marketing ofcampaign merchandise (branded with logos), multilingualoutreach, and mailings to public health professionalsand medical personnel throughout the state. Massparticipation events such as community walks werescheduled in towns throughout the state to reinforce theobjectives of the campaign.

At the completion of the two-month program, itseffects were evaluated. A random sample of residents inNew South Wales was identified for data collectionbefore and after the program, as was a random sample ofresidents of outlying states who did not receive any ofthe materials (a control group).

The main findings from the evaluation of this programare shown in figure 11.1. Residents of New South Walesreported higher physical activity participation levelsat the end of the campaign, whereas people not exposedto the campaign actually showed a statisticallysignificant decline in hours per week of physicalactivity. Other markers of physical activityparticipation showed similar findings. Moreover, thecampaign was quite successful in the target group inincreasing awareness (recognition of the campaign) andknowledge of aspects related to physical activity (e.g.,how much, how often), as well as self-efficacy to becomemore physically active. Although these are short-termfindings (whether the gains remained past the timeperiod of interest is unknown), they quite powerfullyshow that a community-based informational campaign canin fact increase the physical activity behaviors of anentire state.

Figure 11.1   Changes in physical activity participation using acommunity-wide informational campaign: Active Australia.Adapted from Bauman et al. (2001).

Although web-based and electronic physical activity promotionprograms show promise for increasing physical activity levels, thecurrent evidence is inconclusive. The costs of web-based physicalactivity interventions are relatively low, but studies and researchabout their effectiveness need to be more focused on measurableoutcomes as access to and the availability of web-based campaignscontinue to evolve. Combinations of traditional and emerging massmedia campaigns (e.g., face-to-face with electronic follow-up) are

just beginning to become more readily available technologically.Examples of web-based media interventions that have had at leastsome success include several YouTube sites. These are found in thee-Media materials at the end of this chapter, which you should findfun to explore and discuss with your colleagues.

CASE STUDY

VERBThe VERB campaign was the first U.S. national mass mediacampaign to promote physical activity. The campaign wasdeveloped and implemented by the U.S. Centers forDisease Control and Prevention (CDC) in 2002 (Huhman etal. 2005). The purpose of the campaign was to increaseand maintain physical activity among tweens (youth ages9 to 13) throughout the United States. Paid televisionadvertising was used on channels frequented by thetarget audience. Additionally, the program includedradio advertising, websites, and other communicationslinks all designed to make physical activity anattractive, “cool” behavior.

After one year, although the campaign seemed to haveno overall effect on physical activity levels, severalpopulation subgroups did show increases in physicalactivity sessions per week. Girls, younger children,initially inactive children, and other subgroupsreported becoming more active. The campaign did reach amajority of its intended audience, and most children andtheir parents recognized the campaign logo and materialsand understood what it was about; you or an oldersibling may have been part of the VERB campaign!Although not definitive, the results from VERB arepromising in that a large-scale paid media campaignseemed to change physical activity behaviors in some

population groups. Clearly, more research is needed inthis area.

CLASSROOM-BASED HEALTH EDUCATION PROGRAMSAlthough many definitions exist, health education can be roughlydefined as the processes through which people learn about personalhealth concepts and behaviors. Health education curricula havebecome an important part of instructional goals for elementary,middle, and high schools. Classroom-based health educationprograms are usually focused on providing information to helpstudents make rational decisions about adopting healthy behaviors.Ideally, these curricula avoid an overreliance on teaching facts alone.Rather, the more effective health education curricula provideessential information and concepts and then help to shape valuesand norms that will result in positive health behaviors.

Clearly, variability in the quality of health education curricula is tobe expected. Some may not be funded adequately, some may notaddress issues important to the children, and in some cases theinstructor may not be a helpful role model (e.g., teaching childrenabout not smoking while being a smoker!). The Centers for DiseaseControl and Prevention proposed a series of criteria that, takentogether, define an effective health education curriculum. These aresummarized in the highlight box Characteristics of Effective HealthEducation Curricula.

How do informational approaches, such as a community campaignto raise awareness of a new playground, help promote physicalactivity and exercise?

Can information transmitted in classroom-based health educationprograms increase physical activity? Because so many students areexposed to such curricula, the potential for reaching a broadaudience is great. Health education curricula can also supplementphysical education curricula and classes. Ideally, such curriculawould result in changes in self-reported or objectively measuredphysical activity (usually away from school), changes in BMI oradiposity, changes in physical fitness (e.g., aerobic capacity,

strength), improvements in general health knowledge related tophysical activity, and possibly improvements in self-confidence andself-efficacy to be physically active. Some characteristics ofclassroom health education programs attempting to increasephysical activity are as follows:

Provide knowledge and skills for healthy decision making.Work at the individual level (personal and behavioral).Usually include several components (e.g., tobacco use,nutrition, physical activity) and focus on reducing the risk ofchronic disease.Teach behavioral skills, but have no added (in-class) physicalactivity component.

CHARACTERISTICS OF EFFECTIVE HEALTHEDUCATION CURRICULA

Have clearly defined health goals, with behaviors

that are linked to those goals.

Are based on research, but rooted in theory.

Define and describe age-appropriate peer and social

norms for health behaviors, and anchor health values

and beliefs.

Help students understand their own personal risks for

certain health behaviors.

Teach skills for dealing with social pressures to

engage in bad health behaviors.

Teach skills that result in self-confidence and

competence to engage in desired health behaviors.

Provide age-appropriate and culturally appropriate

learning strategies, materials, and examples.

Provide adequate time for instruction, reinforcement

of lessons, and skill and behavioral practice.

Provide opportunities to connect with appropriate

role models such as peers, family members, and

community leaders.

Include support for teachers to enhance their

teaching effectiveness.

Adapted from CDC 2011.

CASE STUDY

COLLEGE-BASED HEALTH EDUCATIONWhat happens to physical activity levels in lateadolescence and early adulthood? Numerous researchershave reported that it declines significantly, whichresults in continued inactivity in most adults. Dr.James F. Sallis and colleagues (1999) designed ProjectGRAD (Graduate Ready for Activity Daily) to study theeffectiveness of a college health education class inincreasing physical activity levels. In the study, 338students ages 18 to 29 years were randomly assigned,after baseline measurements, to intervention or controlgroups. Posttest data were reported for 321 studentsafter one semester, and one and two years afterbaseline. The test group of students took a semester-long course that promoted the adoption and maintenanceof physical activity. The lessons each week were rootedin behavioral science theory designed to supportbehavior change. The control students took a semester-long course on a variety of health education topics.

The GRAD intervention integrated concepts fromexercise science and behavioral science based onnational physical activity recommendations at the timeof the study, social cognitive theory, and behavioral

change theory. The intervention course included a 50minute once per week lecture about physical activity andbehavioral topics, and a weekly 110-minute lab thatincluded 15 minutes of physical activity (no equipment),25 minutes of behavior group discussion, and another 45minutes of varied physical activity with equipment asrequired. Primary measures included assessments ofbehavioral change stage and 7-day Physical ActivityRecall interviews.

The main results of Project GRAD showed no significanteffects on men during the semester-long intervention.Men were more active than women at baseline, at least inthe maintenance stage for physical activity, which mayhave made increases difficult to achieve. The women inthe intervention showed significant increases inphysical activity levels during leisure, strengthening,and flexibility exercises.

Although the reasons for the lack of consistentresults are unclear, the authors hypothesized that theparticipants may not have been far enough along in termsof their readiness to begin physical activity. As aresult of this study, the authors recommended thatstarting earlier (than college) may be a betterapproach. Interestingly, in a follow-up study of ProjectGRAD, Calfas and colleagues (2000) reported nosignificant effects on physical activity outcomes formen or women after two years, despite excellentparticipation in the theoretically based intervention.College-based health education seems to improveknowledge, but not behavior.

Unfortunately, the available scientific evidence does not supportthe use of classroom health education as a method to increasephysical activity behaviors. The Community Guide has concludedthat there is insufficient evidence to determine the effectiveness ofclassroom-based health education programs. The primary findingsshowed little evidence of increased student physical activity levels.As with mass media and other informational strategies, healtheducation does seem to increase general health knowledge,

knowledge related to physical activity, and even self-efficacy aboutexercise. Unfortunately, these increases do not translate intobehavior changes.

LEADER PROFILEUlf Ekelund, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?I think my background might be slightly different frommany other academics. When I was growing up, I loved sportand exercise and wanted to become a physical educationteacher. I was trained in physical education and biologyat the University in Örebro, Sweden, and then worked as ateacher for almost seven years until I was recruited toteach exercise science at my alma mater. I soon realized Ineeded a PhD to obtain a permanent position at theUniversity. I had the opportunity to enroll in thegraduate program at the Karolinska Institute and conductedmy PhD on assessment of energy expenditure and physicalactivity in adolescents. In the late 1990s the developmentof device-based methods for assessing physical activity,such as heart rate monitoring and accelerometry, becameavailable for population-based research and I used thesemethods in my dissertation. While working on my PhD I wasfortunate to be involved in the European Youth Heart Studyand the development of the International Physical ActivityQuestionnaire (IPAQ) and some other projects, which were

amazing opportunities to get to know some of the majorplayers in this field. I was fortunate that when Ifinished my PhD I was offered the opportunity to work atthe Medical Research Council Epidemiological Unit at theUniversity of Cambridge. What I assumed was going to be aone year postdoc experience ended up being almost 10 yearslong. Working in an extraordinary research environment atone of the most prestigious universities in the world wasextremely challenging. My research shifted from beingfocused on the assessment of physical activity into a morebroad epidemiological approach to understanding the roleof sedentary time and physical activity for preventingnoncommunicable diseases across the lifespan, and how totranslate these findings into public health action.

Did any one person have a major influence on your career?How?There are a number of people who influenced my career.When studying physical education and exercise science inSweden during the ’90s I was obviously influenced by thework of Per-Olof Åstrand and Bengt Saltin. During myundergraduate training I took a course in preventivemedicine with Björn Ekblom who really sparked my interestfor research and the importance of physical activity forhealth. During my initial year as a PhD student, I wasfortunate to meet with Chris Riddoch from Bristol at myfirst scientific conference ever (OK, we actually met in apub during the conference) which led to my involvment inthe European Youth Heart Study (never underestimate a pubvisit). However, the most influential academic, who alsorecruited me to Cambridge and allowed me to develop my ownresearch program in physical activity epidemiology is NickWareham. Last but certainly not least, I should alsomention my family who always support me and hardly evercomplain about me working abroad, first in Cambridge andnow in Oslo.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?My research has gradually shifted from being focused onthe assessment of physical activity into anepidemiological approach to understanding the role ofsedentary behaviors and physical activity for preventing

noncommunicable diseases across the lifespan, and how totranslate these findings into public health action. I alsohave a strong interest in population levels and trends ofphysical activity and how to promote physical activity ineveryday life.

Why do you do what you do?Physical activity is one of the most important behaviorsfor health, and I strongly believe that research is neededto inform public health action. Working with greatcolleagues and students in an extraordinary environment atthe Norwegian School of Sport Sciences makes everyday inthe office enjoyable.

What are two key issues that must be addressed by 2030?Along with global warming and reducing carbon dioxideemissions—issues that I truly believe need substantialsocietal changes, including adjustments in how we live ourlives—the global pandemic of physical inactivity needs tobe reversed. I believe these two issues are interlinked interms of public transportation, environmental planning,and clean air.

One of the striking observations from the preceding list ofcharacteristics of classroom-based health education programs forphysical activity promotion is that very few, if any, of the programsfocused solely on physical activity. Usually, the programs includedphysical activity information and education as part of a largercurriculum on reducing the risk factors of chronic disease. Moreover,although many programs focused on developing skills for beingphysically active, they did not provide students with time to actuallybe physically active! Ideally, such a curriculum would focus solely onphysical activity skills and building knowledge around thecharacteristics of effective health education curricula outlined earlier.It is likely that the lack of evidence of program efficacy is becauseprograms have not gone far enough to have a reasonable chance ofsuccess.

In summary, informational approaches to physical activitypromotion seem to increase knowledge, change attitudes, and even

improve self-efficacy about physical activity (i.e., the belief that onecan actually be more physically active). However, concurrentchanges in behavior (what we are interested in) are elusive. The onlystrategy likely to show (short-term) increases in physical activitybehavior is community-wide campaigns. More work is needed in thisarea to better understand it. Can you think of a research questionthat could help?

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

The Community Guide is an ever-expanding resource ofrecommendations on evidence-based interventions toimprove public health.The Task Force categorizes recommendations about specificphysical activity interventions as recommended,recommended against, or having insufficient evidence.Informational approaches may be designed to increaseleisure, occupation, transportation, or at-home physicalactivities.Community-wide campaigns are recommended for physicalactivity promotion and should include strategies to promoteincreased awareness and knowledge, enhance motivationand readiness to change behaviors, and teach or enhancethe skills needed to establish and maintain desired behaviors.Mass media campaigns can be large-scale efforts thataddress messages about physical activity to large andundifferentiated audiences.Mass media campaigns seem to improve awareness andknowledge but alone should not be expected to increasephysical activity.

New media and web-based physical activity interventionsshow promise for increasing physical activity levels, but thecurrent evidence is inconclusive. The costs of web-basedphysical activity interventions are relatively low, but studiesand research about their effectiveness need to be morefocused on measurable outcomes as access to and theavailability of web-based campaigns continue to evolve.Classroom-based health education programs are usuallyfocused on providing information to help students adopthealthier behaviors.Classroom-based health education programs do not seem topromote physical activity behaviors, although they seem toincrease general health knowledge, exercise-relatedknowledge, and exercise self-efficacy.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYBauman A, Bellew B, Owen N, Vita P. 2001. Impact of an

Australian mass media campaign targeting physical activity in1998. American Journal of Preventive Medicine 21: 41-47.

Bauman A, Chau J. 2009. The role of the media in promotingphysical activity. Journal of Physical Activity Health 6 (Suppl 2):S196-S210.

Calfas KJ, Sallis JF, Nichols JF, Sarkin JA, Johnson MF, et al.2000. Project GRAD: Two-year outcomes of a randomized

controlled physical activity intervention among young adults.American Journal of Preventive Medicine 18: 28-37.

Centers for Disease Control and Prevention. 2011. Characteristicsof an Effective Health Education Curriculum.www.cdc.gov/healthyyouth/SHER/characteristics/index.htm.Accessed 23 July 2011.

Heath G. 2009. The role of the public health sector in promotingphysical activity: National, state, and local applications. Journalof Physical Activity Health 6 (Suppl 2): S159-S167.

Huhman M, Potter LD, Wong FL, Banspach SW, Duke JC,Heitzler CD. 2005. Effects of a mass media campaign toincrease physical activity among children: Year-1 results of theVERB campaign. Pediatrics 116: 277-284.

Kahn EB, Ramsey LT, Brownson RG, Heath GW, Howze EH,Powell KE, Stone EJ, Rajab MW, Corso P, Task Force onCommunity Preventive Services. 2002. The effectiveness ofinterventions to increase physical activity. American Journal ofPreventive Medicine 22: 73-107.

Sallis JF, Calfas KJ, Nichols JF, Sarkin JA, Johnson MF, et al.1999. Evaluation of a university course to promote physicalactivity: Project GRAD. Research Quarterly for Exercise andSport 70: 1-10.

U.S. Department of Health and Human Services. 2008. PhysicalActivity Guidelines for Americans. Washington, DC: U.S.Department of Health and Human Services.www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services, Public HealthService, Centers for Disease Control and Prevention, NationalCenter for Chronic Disease Prevention and Health Promotion,Division of Nutrition and Physical Activity. Brown DR, HeathGW, Martin SL, eds. 2010. Promoting Physical Activity: AGuide for Community Action, 2nd ed. Champaign, IL: HumanKinetics.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.1.1, 1.1.5, 1.3.1, 1.3.2, 1.3.3, 1.4.1, 1.4.2, 2.1.1,2.1.3, 2.2.1, 2.2.2, 2.3.2, 2.3.3, 2.5.2, 3.1.1, 3.1.2,3.2.1, 3.3.3, 3.7.1, 4.1.1, 4.1.2, 4.1.4

CHAPTER 12School-Based Approaches toPromoting Physical Activity

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The rationale for school-based programming to increasephysical activity

»  The current U.S. policies and strategies for schoolphysical activity programs along with the components ofeffective school-based interventions

»  The current status of physical activity levels for childrenand adolescents globally

»  The potential physical activity and exercise outcomes foryouth

»  The evidence and guidelines for physical activity andexercise for youth

»  Examples of school-based programs that increasephysical activity

OPENING QUESTIONS»  Can and should schools implement physical activity programs?»  What are the components of an effective school physical

activity program?

»  What are some successful models of school-based physicalactivity programs?

School-based physical activity programming, such as physicaleducation (PE) and sport participation (athletics), have been part ofschool culture for over 100 years in the United States and manyother countries. Physical educators and coaches promote exerciseto youth and young adults in schools to help them achieve orimprove their physical fitness and athletic performance. Since 2005,the national focus for PE and athletics in U.S. schools has shiftedsomewhat to promoting physical activity for all students (more so inPE) and promoting student health and safety (more so in athletics).Schools today are also looking to promote physical activity at allgrade levels in school venues other than just PE and athletics.Enhanced school-based PE is a recommended strategy that worksto increase physical activity (Kahn et al. 2002, IOM 2013).

In addition to PE, schools are increasingly looking to integratephysical activity into other parts of students’ lives. Current best

practices include prekindergarten (pre-K) programs, kindergartenprograms, before-school programs, classroom activity breaks,recess breaks, after-school programs, commercially sponsoredprograms, active transport, and summer (seasonal) programs.

RATIONALE FOR SCHOOL-BASED PHYSICAL ACTIVITYPROGRAMSThis chapter is based on several detailed reports (IOM 2013; Kahnet al. 2002; Massengale 1987; Murray et al. 2019; Siedentop 2009)and the Guide to Community Preventive Services (Community Guide2019), which support the promotion of physical activity via theeducation sector.

In the United States, schools have been involved in the publichealth and safety of children and adolescents since colonial times.Initially, schools helped combat infectious diseases; today they arebeing asked to lead the way in preventing and controlling theincidence of obesity, overweight, and diabetes (see chapters 5 and 6for more). In the United States it has been estimated that over 56.6million children and adolescents attend public and privateelementary and secondary schools, where they spend approximately6.5 hours per day for an average of 180 days per year. Additionally,over 1.4 million children attend pre-K schools, and over 12.2 millionolder adolescents and young adults (<25 years) attend communitycolleges or universities.

Because of the number of students they serve, schools at alllevels are attractive public venues that can disseminate positivephysical activity messages and promote active lifestyles. Mandatingincreased physical activity in schools has also become popularrecently, because policy makers believe that it can improveadherence to varied curricular-based education to combat youthobesity, overweight, and diabetes, versus relying on students’voluntary compliance to lifestyle change.

National legislation in the United States, including the 2004 ChildNutrition and WIC Reauthorization Act (Lee et al. 2006), ties school

funding to items such as school wellness policies that includepromoting healthy eating and physical activity. National goals suchas those contained in Healthy People 2010 and Healthy People2020 (HP2020) also encourage curricular goals in school PE thatinclude having students work at vigorous or moderate intensities forat least 50% of class time. The National Physical Activity Plan(NPAP) contains specific strategies and tactics to promoteComprehensive School Physical Activity Programs (CDC) andhigh quality PE programming.

HEALTHY PEOPLE 2020Healthy People 2020, the most recent version of the healthgoals that are updated every 10 years by the U.S.Department of Health and Human Services, highlightsdisparities and opportunities for health improvement bysetting public health targets to achieve in a 10-yearperiod. Several objectives promote increased physicalactivity levels that are, or could be, school related.Following are some of the physical activity–related HP2020objectives that target children and adolescents:

Increase the proportion of adolescents who meet

current federal guidelines for aerobic physical

activity and for muscle-strengthening activity.

Increase the proportion of the nation’s public and

private schools that require daily PE for all

students.

Increase the proportion of adolescents who

participate in daily school PE.

Increase regularly scheduled elementary school

recess.

Increase the proportion of school districts that

require or recommend elementary school recess for an

appropriate period of time.

Increase the number of states that require licensed

child care programs to provide physical activity.

Increase the proportion of the nation’s public and

private schools that provide access to their physical

activity spaces and facilities for all people outside

of normal school hours (i.e., before and after the

school day, on weekends, and during summer and other

vacations).

Although PE curricula have become the main focus for increasingphysical activity in schools, youth cannot realistically meet physicalactivity guidelines (60 minutes per day; see the section on scientificevidence later in the chapter) by being active only in PE class. Eventhe very best physical education classes can offer on average only20 to 30 minutes of physical activity time. Youth should beencouraged to acquire physical activity before, during, and afterschool in a variety of other ways, such as active transportation, play,sports, and leisure or recreation (IOM 2013). A whole-schoolapproach is recommended by the Health and Medicine Division ofthe National Academies of Sciences, Engineering, and Medicine, asdiagrammed in figure 12.1. The model shown representsapproximately 11 hours each day in which physical activityopportunities for children and adolescents might be incorporated,and provides many options for achieving the nationalrecommendations of 60 minutes per day.

Does physical activity make children and adolescents smarter?Emerging evidence on brain function outcomes in relation toparticipation in physical activity and exercise indicates that there aremany positive associations (see chapter 9 and figure 9.2 for more).Importantly, participation in physical activities like those described inthe whole-school approach have not been shown to negatively affectacademic performance.

Additionally, it is also important to note that professionalorganizations like SHAPE America (Society of Health and PhysicalEducators) provide recommended PE guidelines for children andadolescents in schools. The guidelines address teaching structuresand administrative issues that can further promote physical activityparticipation in schools.

Schools are a major source of potential influence on children andadolescents to adopt active lifestyles. Other sectors in society suchas government agencies, families, and the media can likewiseinfluence the adoption of behaviors that can help children andadolescents achieve caloric balance (Pate and Dowda 2019). Untilrecently, schools were built in neighborhoods, which often positivelyaffected the whole community in relationship to physical activity,because they were within walking distance for most students andincluded places at which youth and adults could be active (e.g., opengreen spaces, outdoor tracks, indoor and outdoor basketball courts,gyms). Schools have also traditionally offered opportunities forphysical activity through PE classes, recess, and organized sports.However, with the new accountability requirements such as those ofthe No Child Left Behind legislation (2001), which encourageschools to focus on academic subjects such as mathematics andreading, physical education and recess time continue to besqueezed out.

Figure 12.1   The whole-school approach is designed to promote schools as ahub encouraging physical activity for children and adolescents for 60minutes each time they visit campus.Adapted from Institute of Medicine (2013).

Adding to these challenges, most new schools are being built onthe outskirts of cities as a result of urban sprawl. This trend reducesopportunities for physical activity for members of the schoolcommunity, because students must be bused to school or driven byfamily members. Research shows that whether schools are new orold, parents are concerned about safety, injury, and crime, which cancause them to limit physical activity opportunities for their children ifthey perceive the school environment to be unsafe.

KINESIOLOGY AND PHYSICAL ACTIVITY OUTCOMES FORYOUTHSelected chronic adaptations to physical activity and exercise arelisted in the highlight box Adaptations to Physical Activity andExercise Programming for Youth. The amount of physiologicaladaptation related to each of the identified benefits is dosedependent and influenced by the physical training principles

discussed in chapter 2 and reviewed by Strong and colleagues(2005).

The exercise science–related benefits of physical activity forchildren, adolescents, and young adults are highly dependent onindividual growth and development. Most youth experience verypositive benefits associated with engaging in physical activity andexercise; however, maturation can influence the rate and timing ofspecific training adaptations.

ADAPTATIONS TO PHYSICAL ACTIVITY AND EXERCISEPROGRAMMING FOR YOUTHPhysiological

Increased O2maxIncreased strength

Improved muscular endurance

Increased HDL levels

Lower triglyceride levels

Improved insulin levels

Lower blood pressure

Lower percentage of body fat

Reduced risks for metabolic dysfunction

Reduced risks for type 2 diabetes

Improved bone health

Biomechanical

Improved economy with age

Improved balance

Improved mobility

Increased motor skill and confidence to engage

further in physical activity and exercise

Improved proprioception

Behavioral

Increased self-confidence

Improved self-efficacy

Improved self-esteem

Decreased depression and anxiety

Experience with behavioral change

Physiologically, participation in regular physical activity can helpyouth increase cardiorespiratory endurance ( O2max or O2peak) by8 to 10%. Children and adolescents can increase their strength andmuscular endurance; however, strength gains prior to puberty aremostly due to neural changes (i.e., better muscle recruitment) ratherthan hypertrophy (i.e., increased muscle size). There are publishedrecommendations that pertain to youth strength and muscularendurance training (see Kenney, Wilmore, and Costill 2020 formore).

Youth can achieve significant and consistent improvements inbone health by participating in weight-bearing and muscular strengthand endurance activities. The opportunity for increased bone massin girls and boys occurs in premenarche and puberty. Their risks formetabolic dysfunction (e.g., issues related to HDL, triglyceride, andinsulin levels; blood pressure; and percentage of body fat) and type2 diabetes are also significantly reduced if they can get 60 minutesor more of physical activity daily.

Youth can experience many of the same biomechanical benefitsreported for adults and older adults, particularly if they have theopportunity to develop a range of motor skills by participating in avariety of physical activities. As children move through adolescenceto young adulthood, they experience improved economy (i.e., lowerenergy cost) in activities such as running. Changes in economy havebeen attributed to changes in body size and perhaps in stridefrequency.

Youth engaged in organized sports have been reported to suffermore injuries that might limit future physical activity (particularly ifthey do not participate safely with protective equipment) thannonparticipants. However, except for information from descriptivestudies of high school athletes, there is little evidence for this claim.Research on participation in school-based PE suggests that it is avery safe undertaking for the vast majority of students participating.

Behaviorally, the experiences that children (including pre-K andkindergarten students) have with physical activity, and the earlybehaviors that they develop as a result of participation, are thoughtto be critical to whether they become and remain active throughadolescence and adulthood. Those who do not have theopportunities to develop the motor skills by participating in a varietyof physical activities (as part of leisure time, recreation, PE, sports,and games) are most likely to become inactive, obese, or overweightadolescents, adults, and older adults.

SCHOOL-BASED PHYSICAL ACTIVITY AND PHYSICALFITNESS ASSESSMENTS OF YOUTHA discussion of all the physical activity and fitness assessments thatpertain to children and adolescents is beyond the scope of this text(see Morrow 2009 for more). However, it is important to point out thatthe assessment techniques discussed in chapter 4 have been usedextensively in school-based physical activity intervention evaluations.

Two frequently used comprehensive fitness assessment programsare Fitnessgram and the Presidential Youth Fitness Program.They are comprehensive field assessments of physical fitness inchildren and adolescents, and both contain a variety of valid andreliable fitness tests (that provide teachers with options and advice),with age-appropriate interpretations, and strategies andprogramming to increase or maintain physical activity. Fitnessgramand the Presidential Youth Fitness Program are school friendly andcan be used as in-service programs for teachers and healthprofessionals.

Fitnessgram was first developed in 1982 by the Cooper Institute inresponse to the need for a comprehensive set of assessmentprocedures for PE programs. The assessment includes health-related physical fitness field tests that assess aerobic capacity;muscular strength, muscular endurance, and flexibility; and bodycomposition. Scores from these assessments are compared tohealthy fitness zone standards to determine students’ overallphysical fitness levels, and areas for improvement are suggestedwhen appropriate. An activity assessment included in theFitnessgram software enables students to record their physicalactivity over time during the school day, and generates a reportshowing the total minutes of activity, periods of activity time eachday, and types of activity.

The mission of the President’s Council on Sports, Fitness andNutrition is to increase sports participation among youth of allbackgrounds and abilities, and to promote healthy and activelifestyles for all Americans. The Presidential Youth Fitness Programis a comprehensive school-based program that promotes health andphysical activity for America’s youth. The program includes onlinechallenges and allows participants to keep track of their progresstoward individual goals.

Although many have argued that physical fitness tests should beabandoned in schools, physical fitness testing of youth seems tohave gained momentum in recent years; California and Texas bothmandate fitness testing of students in several grades. The idea isthat testing health-related fitness parameters will help integratebehavior, fitness, motor skills, and cognition to encourage morephysical activity in and out of school. Policy makers have usedfitness evaluation results, at least in part, to make the case thatchildren and adolescents score low on health-related fitness, andtherefore need to become more active and fit.

McKenzie (2007), Morrow (2005), and others have reviewed thenumerous pitfalls associated with youth fitness testing, particularly inschool PE. For public health practitioners, the most notable point to

remember is that the relationship between measures of physicalfitness (i.e., physiological constructs) and physical activity (behavior)is relatively weak. Further, youth fitness performance is influenced bygenetics, growth and development, and maturation. Thus, veryinactive children may do very well on school field tests of physicalfitness, whereas others who may be meeting or exceeding theguideline of 60 minutes per day may not do well on some or all of thetests. It remains to be determined whether physical fitness testing ofchildren and youth promotes more physical activity in these groups,and whether the strategy has a significant impact on the prevalenceof obesity, overweight, and diabetes.

Do children and adolescents like competition in school PE? Doesit help promote physical activity? Why?

PHYSICAL ACTIVITY IN CHILDREN AND ADOLESCENTSImportant considerations concerning physical activity promotion inchildren and adolescents are their individual growth trajectories andthe fact that older children have more developed motor skills thanyounger ones. We all know that some children mature faster thanothers. This results in differences in motor ability among individuals

of similar ages as well as across the age range. Fourteen-year-oldshave better gross motor control, more muscle mass, and generallyhigher fitness than younger children, for example. This difference inphysical abilities due to growth and development can affect manyaspects of physical activity behavior, both physical andpsychological.

Changes in motor ability for a number of fitness parameters areillustrated in figure 12.2 for youth ages 6 to 17. Clearly, children atdifferent ages differ in their test results that measure flexibility,muscular strength, and aerobic fitness. Further, sex differences areto be expected, particularly as children grow into adolescence. Thedata in this figure illustrate that many physical performanceoutcomes for youth are related to growth, development, andmaturation, and they vary by sex. Understanding theinterrelationships among growth, maturation, and exercise is criticalfor designing and implementing meaningful physical activityprograms for children and adolescents.

SCIENTIFIC EVIDENCEThe 2008 Physical Activity Guidelines Advisory Committee (PAGAC)found that strong scientific evidence supported a consistent effect ofphysical activity and exercise on cardiorespiratory fitness andmuscular strength in children and adolescents ages 6 to 17 (U.S.Department of Health and Human Services [USDHHS], PAGAC2008). They also found strong evidence that physical activity andexercise are positively associated with body composition,cardiorespiratory and metabolic health, and bone health; higherlevels of physical activity are associated with more favorableoutcomes. The evidence correlating to mental health benefits (nowreferred to as brain health) for active youth was moderate fordepression, weak for anxiety, and limited for self-esteem.

Figure 12.2   Changes in motor ability from the ages of 6 years to 17 years.Reprinted by permission from J. Wilmore, D.L. Costill, and L.W. Kenney, Physiology ofSport and Exercise, 5th ed. (Champaign, IL: Human Kinetics, 2012), 441. Data from thePresident’s Council on Fitness and Sports 1985.

The 2018 PAGAC additionally focused on the scientific evidencebetween physical activity and health outcomes for children under 6years of age and the health outcomes of sedentary behaviors forchildren and adolescents. The findings of the 2018 PAGAC reportare more robust than the 2008 PAGAC, but confirm and extend therecommendations for daily physical activity for children and youth,ages 3 to 17.

Strong evidence indicated that higher amounts of physical activitywere associated with more favorable indicators of bone health andwith reduced risk for excessive increases in body weight andadiposity in children ages 3 to 6 years. Insufficient evidence wasavailable to determine the effects of physical activity oncardiometabolic risk factors, the dose for health effects, ormoderating factors like age, sex, race, ethnicity, weight status, orsocioeconomic status in children under 6 years of age,

The 2018 PAGAC updated evidence for 6 to 17 year olds withregard to physical activity and health outcomes, supporting the 2008PAGAC except for finding moderate (as compared to strong)evidence for physical activity and cardiometabolic health.Additionally, the committee found that children and adolescents whoengage in regular moderate-to-vigorous physical activity significantlyincrease their cardiorespiratory fitness, and those participating inresistance training significantly increase their muscular fitness.

Evidence of a dose-response relationship between physicalactivity and exercise and cardiorespiratory and metabolic health inyouth has not been specifically determined, and more dose-response studies are needed for evaluating other health outcomes inyouth. There is strong evidence that physical activity and exercisehas positively affected youth fitness levels for boys and girls.Evidence of effects of age, sex, and race or ethnicity on bodycomposition, cardiorespiratory and metabolic health, and mentalhealth in youth is unclear. A strong association has been shownbetween physical activity and exercise and bone health for both boysand girls, and it is influenced by growth, development, andmaturation. Children should initiate physical activity at least by theearly teen years to maximize physiological benefits.

Many studies have demonstrated significant gains in physicalfitness measures (cardiorespiratory and muscular) in children andadolescents who participated (60 minutes per day recommended) inmoderate- to vigorous-intensity aerobic activities three or more daysper week, and muscle-strengthening and bone-strengthening

exercises two or three days per week. Cardiorespiratory andmetabolic health are also significantly improved by taking part invigorous-intensity aerobic activities at least three days per week, andbone health also responds positively to weight-bearing activitiesperformed at least three days per week.

With regard to time spent by youth in sedentary behaviors, the2018 PAGAC found limited evidence for poorer health outcomes inchildren and adolescents. The evidence was somewhat stronger forvarious health outcomes for television viewing or screen time thanfor total sedentary time.

GUIDELINESThe guidelines for physical activity for youth were initially highlightedin chapter 5. The 2018 edition of Physical Activity Guidelines forAmericans includes new recommendations for preschool-agedchildren to acquire three or more hours of light, moderate, andvigorous physical activity daily:

Preschool-aged children (ages 3 to 5) should be physicallyactive throughout the day to enhance growth and development.Adult caregivers of preschool-aged children should encourageactive play that includes a variety of activity types.In addition, children and adolescents (ages 6 to 17) shouldengage in at least 60 minutes per day of moderate- or vigorous-intensity physical activity (including aerobic, muscle-strengthening, and bone-strengthening activities) for at leastthree days per week. Youth should be provided opportunitiesand encouragement to participate in physical activities that areage-appropriate, enjoyable, and offer variety.

It is also important to know some strategies for replacing inactivitywith activity. Following are some suggestions for getting youth activeand encouraging them to stay active by meeting the guidelines(USDHHS, PAGAC 2008, 2018):

Children and adolescents who are inactive or doing lessphysical activity than the guidelines suggest should slowlyincrease their moderate-to-vigorous physical activity in waysthey enjoy. A gradual increase in the number of days and thetime spent being active will reduce the risk of injury and isconsistent with the basic principles of exercise physiologycovered in chapter 2.Children and adolescents who meet the recommendedguidelines should continue doing moderate-to-vigorous physicalactivity on a daily basis and, if appropriate, become even moreactive. Evidence suggests that more than 60 minutes of activityper day may provide additional health benefits.Children and adolescents who exceed the guidelines shouldmaintain their activity level and vary the kinds of activities theydo to reduce the risk of overtraining or injury.Youth with disabilities will most likely be less active than thosewithout disabilities and should specifically be encouraged towork with healthcare professionals to incorporate physicalactivity into their lifestyles, using adjustments to accommodatetheir physical and mental challenges. They should be alsoencouraged to do as much physical activity as possible toachieve the guidelines and avoid being inactive.

INTERNATIONAL AND NATIONAL TRENDS IN YOUTHPHYSICAL ACTIVITY LEVELSAs you have learned in previous chapters, physical inactivity andinsufficient activity to meet current recommended physical activitylevels are associated with increased mortality (fourth leadingnoncommunicable cause of death). However, engagement in regularphysical activity has been shown to be a key factor for physical,physiological, developmental, mental, cognitive, and social health forchildren and adolescents. Yet it is estimated that 80% of youth (ages

11-17) worldwide do not obtain the recommended 60 minutes ofmoderate-to-vigorous physical activity daily (Sallis et al. 2016).

The Global Matrix initiative is part of an incorporated nonprofitorganization that includes collaborating researchers, healthprofessionals, and stakeholders to provide assessment andawareness of physical activity in children and older youth globally(Aubert et al. 2018). The results of a Global Matrix Report Cardbased on 10 indicators of physical activity (overall physical activity,organized sport and physical activity; active play; activetransportation; sedentary behaviors; physical fitness; family andpeers; school, community and environment; and government) foryouth in 49 countries were published in 2018. Data from 49 countrieswere analyzed based on the physical activity indicators andclassified into three categories using the United Nation’s humandevelopment index (HDI) of low and medium, high, and very high.Overall, average grades of C-, D+, and C- respectively werereported for low and medium HDI countries, high HDI countries, andvery high HDI countries. The HDI is based on varying education, lifeexpectancy, and income per capita data in countries globally.

The results of the Global Matrix initiative study provide specificworldwide data about indicators of youth physical activity. The datapresents public-health physical activity practitioners with insight forfuture development of effective strategies to increase physicalactivity opportunities for youth.

In the United States, Katzmarzyk and colleagues (2018) havesummarized the results of the 2018 U.S. Report Card on PhysicalActivity for Children and Youth. The data were collected as part ofthe National Physical Activity Plan with various national dataresources, and used the same indicators as those describedpreviously for the Global Matrix initiative. The authors also providedrationales for the ratings which can be found in their report. Thefollowing grades were assigned for 10 indicators:

Overall physical activity: D-

Sedentary behaviors: DOrganized sport participation: CActive play: Incomplete (based on insufficient data)Active transportation: D-Physical fitness: CFamily and peers: D-School: D-Community and environment: CGovernment: Incomplete (no data)

As you can see, the authors found poor grades for the 2018 U.S.Report Card on Physical Activity for Children and Youth thatindicates insufficient participation in physical activity. The results(with rationales for each indicator) provide U.S. public-healthphysical activity practitioners with evidence-based data (in additionto international data) to develop effective strategies to increaseopportunities for physical activity among children and youth.

SCHOOL-BASED PHYSICAL EDUCATIONSince the early 1990s, school PE programs have focused on health-related PE (HRPE) (McKenzie 2007). The HRPE concept promotespublic health objectives and focuses on the health benefits ofphysical activity. This focus on behavior rather than physiologicalstatus is important because for many years, school PE was primarilyfocused on sport performance and yearly fitness testing. Studentswere usually not prepared for the fitness tests; therefore, they scoredpoorly and became turned off to becoming fit. In fact, many oftoday’s public policy makers themselves experienced PE in “asetting in which embarrassment, humiliation, anger, discomfort,noninvolvement, apathy, rebellion, compliance, and irrelevantbehavior appear to be the norm” (Massengale 1987). Perhaps it isnot too hard to understand why resistance to promoting school PEthrough HRPE continues, both inside and outside the PE profession.

Can participating in youth sports promote physical activity andexercise for a lifetime?

As covered in chapter 11, the Community Guide (Kahn et al.2002; Community Preventive Services Task Force 2014) is aresource for evidence-based disease prevention and health-promotion strategies. One of the strategies that works is high-qualityphysical education. Outcomes of interest in studies of PE include theamount of time (days per week and minutes per period) as well asthe amount of time per period that students spend being physicallyactive in PE class. Additionally, physiological outcomes such asimprovements in physical fitness and changes in body compositionhave been investigated. The studies of the effectiveness of schoolPE in increasing physical activity suggest the following:

The amount of time spent in moderate- or vigorous-intensityphysical activity during PE class should be increased by usinginstructional strategies that extend physical activity time (e.g.,modifying rules of game, substituting less active games withmore active ones). Time spent in moderate- or vigorous-intensityphysical activity has been shown to increase on average about10%.

Physical education lesson plans should incorporate fitness andother training activities.

These recommendations have been evaluated in studies thathave involved lengthening the time period of existing PE classes,adding new PE classes, and increasing the amount of timededicated to moderate- to vigorous-intensity physical activity duringclass without lengthening class time.

Crucial to the Community Guide recommendations for PE is theuse of high-quality studies. The studies reviewed were not those inwhich a ball was rolled out during a PE period or students were linedup to shoot basketballs one at a time. Instead, the Community Guiderecommendations are based on studies of high-quality PE programsthat include all students, have appropriate class sizes, usedevelopmentally (age-) appropriate curricula delivered by trained PEspecialists, have adequate equipment to meet educational goals,focus on an appropriate mix of motor skills, increase studentunderstanding, and provide active opportunities to practice. Thesecharacteristics (and others) are encouraged by SHAPE America, theprimary association for physical education professionals in theUnited States. PE works when it is high-quality PE. The training ofnew PE professionals who can integrate the modern concepts of PEand public health are better prepared to deliver effective physicalactivity programs (Murray et al. 2019).

Several commercial school-based PE programs are available toenhance the PE curricula of primary, middle, and secondary schools.Most of these programs have been tested with positive results. A listof these resources is found in the web resource.

Physical education is not the only aspect of health that schoolscan affect. Because such a large proportion of children are enrolledin schools, it is a logical place to help them learn and practicehealthy behaviors. The primary public health framework forpromoting school health, including increased physical activity, is theWhole School, Whole Community, Whole Child (WSCC) Model

developed by the CDC and the Association for Supervision andCurriculum Development. The WSCC Model consists of the following10 interactive components:

Health educationPhysical education and physical activityNutrition environment and servicesHealth servicesCounseling, psychological, and social servicesSocial and environmental climatePhysical environmentEmployee wellnessFamily engagementCommunity engagement

From CDC, www.cdc.gov/healthyyouth/wscc/model.htm.

OPPORTUNITIES FOR SCHOOL-RELATED PHYSICALACTIVITYDespite the fact that schools are a helpful place topromote physical activity because of the sheer numbers ofstudents there, even the best PE classes cannot providethe entire recommended 60 minutes per day of physicalactivity that children and adolescents need. TheComprehensive School Physical Activity Program (CSPAP) isa school-based, multicomponent approach that is designedto increase physical activity. Enhanced PE is thefoundation of CSPAP but it also includes before- andafter-school programs; in-class physical activity breaks;physically active learning activities, and connections tofamily and community resources (Pate and Dowda 2019). Manyof these strategies are showing promise in adding physicalactivity opportunities to the day for children andadolescents, but the full impact of CSPAP’s fivecomponents for increasing physical activity remains to bedetermined.

CASE STUDY

THE SPARK PROGRAMThe Sports, Play, and Active Recreation for Kids (SPARK)program is a comprehensive health-related PE program forelementary school children. The program promotes the useof enjoyable physical activities during PE classescoupled with teaching movement skills. Children areactive in moderate- or vigorous-intensity physicalactivity for most of a PE class period; approximately50% of the time is devoted to health-related physicalactivity, and 50% to skill building. In addition to theweekly modules in health-related physical activity andskill-related sports, the program also includes anemphasis on self-management skills and homework designedto engage parents.

In their evaluation of the program, Sallis andcolleagues (1997) randomly assigned seven schools(nearly 1,000 elementary school students) to the SPARKprogram or the usual PE program (control). The SPARKschools were further randomly assigned to one of twoconditions: one in which PE classes were led by trainedPE specialists, and the other in which PE classes wereled by classroom teachers with no special training inPE. After two years of implementation, schools with theSPARK program achieved significantly more minutes perweek of physical activity during PE classes than did thecontrol schools (see figure 12.3). Further, students inclasses that were led by trained PE specialists spentthe most time being physically active. High-qualityphysical education promotes physical activity.

Figure 12.3   Effects of a health-related physical education program(SPARK) on minutes per week of physical activity in elementaryschool children.Adapted from Sallis et al. (1997).

DEVELOPMENTAL CONSIDERATIONS FOR PHYSICALACTIVITY IN YOUTHThe maturation, growth, and development factors (roughly, althoughnot perfectly, estimated by the child’s age) that affect physical fitnessand were discussed earlier have implications for strategies topromote physical activity among children and adolescents. Clearly,

different approaches are needed depending on age, sex, anddevelopmental stage. High-quality school PE curricula should takesuch differences into account. Figure 12.4 shows how the emphasisof PE programs should change as children mature.

During the preschool and elementary school years, the emphasisof PE programs should be on engaging in general physical activitythat develops and improves motor skills (locomotor, such astraveling, fleeing, and dodging; nonmanipulative, such as jumping,landing, and balancing; and manipulative, such as kicking, throwing,and catching). Participation in activities that develop physicalcompetence, offer choices, maximize fun and enjoyment, andminimize anxiety (e.g., games and lead-up sports) can positivelyinfluence children’s activity levels.

Figure 12.4   Changing emphasis of physical activity during childhood andadolescence.Adapted by permission from R.J. Park and M.H. Eckert, eds., New Possibilities, NewParadigms? American Academy of Physical Education Papers 24. (Champaign IL: HumanKinetics, 1991), 30-38.

Once students reach the ages of 10 to 14, the emphasis onphysical activity should shift toward individual and group activities,including school and club sports. Because time in school PE usuallydecreases for this age range, teachers should focus on factors thatencourage youth to adopt and maintain physical activity levels, suchas the following:

Being active with friendsHaving fun and developing the skills needed for performingactivities of choiceHaving time for physical activities at which they feel competentSharing time with adults who are positive role models forphysical activityAccess to neighborhood facilities to engage in leisure-timeactivitiesGood parent–adolescent communicationSelf-esteemAccess to equipment

For older adolescents (ages 15 to 18), more structured physicalactivity programs that help them transition toward adulthood arerecommended. This age group is quite vulnerable to becomingsedentary, losing caloric balance, and gaining weight rapidly as theybecome more independent. The emphasis for young adults shouldbe on health, fitness, and behaviors that can be adopted andmaintained in adulthood. Those attending community colleges oruniversities should be encouraged to participate in physical activityclasses to establish or maintain skills for active living.

In summary, numerous methods have been, or can be,implemented in schools to increase students’ physical activity levels.Although high-quality PE is the primary evidence-based strategy thathas been shown to increase physical activity, others have beeninvestigated and are showing promise. High-quality PE programsdelivered by trained physical educators seem to have the greatest

impact on physical activity in schoolchildren. The evidence thatphysical activity and physical fitness can positively affect academicachievement is accumulating, but the cost-effectiveness of school-based PE and physical activity interventions has not been evaluated.Fortunately at the present time, public health physical activitypractitioners have numerous resources (e.g., HP 2020, NPAP,CSPAP, IOM 2013, and the Community Guide) to assist them in thedevelopment and implementation of school-based physical activityprogramming.

LEADER PROFILEPeter Silvius, MS

Why and how did you get into the field of PhysicalActivity and Public Health?This is the 20th year that I have worked in publiceducation. My first job was in adapted physical education,and I quickly learned how movement and play could supporthappiness. I had always been intrigued by the correlationof physical activity and social-emotional wellness. Thisinterest led me to focus on issues related to studentbehavior, learning readiness, and facility design. I havefound that if access to physical activity is intentionallyestablished as a foundation, our expected outcomes will bemore attainable and sustainable.

Did any one person have a major influence on your career?How?I have had several mentors in my life that continue to bemajor influences on my understanding of the world and myrole and responsibility within it—Dr. Bill Squires is oneof these mentors. Dr. Squires has helped me to understandthe importance and responsibility of a public school forour communities, and that the public school is “sacred

ground” where we seek equity and safety for all.What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?In the school district where I work we recently adopted anew policy to increase recess time for all elementarystudents by providing unstructured outdoor play beforeevery hour of lesson time. I believe that this change isgoing to be transitional for our community and willbenefit the educational and health outcomes for ourstudents and improve community wellness as a whole. Withour new approach, all elementary students will have accessto an hour of outdoor, unstructured recess every day inaddition to their scheduled physical education class.

Why do you do what you do?The people I work with motivate me as does the communityof students and citizens I work for. When asked about mywork, I often respond, “I get to do all the fun stuff—thefoundational stuff that really matters.” After 20 years inthe field, I now see the fruits of my efforts and I have aclear sense of my core values. I feel proud of the manysmall gains that we have made in my home school districtand I look forward to building on these successes in thefuture.

What are two key issues that must be addressed by 2030?We must continue our efforts to reengineer activity intoour lives. In most communities we have made driving a carthe safest and easiest option for even the shortest trips.We must make walking and biking easier and safer by meansof bike lanes and sidewalks. These changes can be easy tomake if resources are directed toward activetransportation.

Our schools need to address lifelong recreation skills.Our secondary physical education programs need to focusskill development on lifelong forms of recreation. Team-sport–related skill development does not provide theskills needed for a lifetime of activity. We need to teachour children to understand the benefits of outdoorrecreation and to understand the need for fresh air andnatural spaces as a vital aspect of our physical, social,and emotional health.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

In the United States, over 56.6 million children andadolescents attend public and private elementary andsecondary schools, where they spend approximately 6.5hours per day for an average of 180 days per year.Additionally, over 1.4 million children attend pre-K schools,and more than 12.2 million older adolescents and youngadults (< 25 years) attend community colleges or universities.This makes schools very attractive environments in which topromote physical activity.There is no evidence that time spent in physical activity or PEhas negative influences on academic achievement, andemerging evidence suggests that physical activity positivelyinfluences academic achievement.The primary Whole School, Whole Community, Whole Child(WSCC) components that U.S. educators are encouraged touse to promote increased school physical activity are healtheducation; physical education and physical activity; nutritionenvironment and services; health services; counseling,psychological, and social services; social and emotionalclimate, physical environment; employee wellness; andcommunity involvement.

The Community Guide recommends high-quality school PEas an evidence-based strategy to promote physical activity.The health-related PE (HRPE) concept promotes publichealth objectives and encourages students to become morephysically active, rather than just focusing on physical fitness,which was the desired product or outcome of PE in the past.In addition to PE, schools can increase youth physical activitylevels through before-school programs, classroom activitybreaks, recess breaks, after-school programs, sports andintramural programs, and summer (seasonal) programming.During the preschool and elementary school years, school-based programs to increase physical activity shouldemphasize general physical activity and improving the motorskills (locomotor, such as traveling, fleeing, and dodging;nonmanipulative, such as jumping, landing, and balancing;and manipulative, such as kicking, throwing, and catching).Once students reach the ages of 10 to 14, the emphasisshould shift toward a variety of individual and group activities,including school and club sports.The emphasis for young adults should be on health, fitness,and behaviors that can be adopted and maintained intoadulthood.The exercise-related benefits for children, adolescents, andyoung adults are highly dependent on individual growth anddevelopment. Most youth can experience the very positivebenefits of engaging in physical activity and exercise;however, maturation can influence the rate and timing ofthese training adaptations.The guidelines for physical activity participation for preschool-aged children (ages 3 to 5) encourage physical activity (light,moderate, and vigorous activities) throughout the day for upto three hours or more to enhance growth and development.Children and adolescents ages 6 to 17 should engage in at

least 60 minutes per day of moderate- or vigorous-intensityphysical activity (including aerobic, muscle-strengthening,and bone-strengthening activities) for at least 3 days perweek.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYAubert A, Barnes JD, Abdeta C, Nada PA, Adeniyi AF. et al. 2018.

Global Matrix 3.0 physical activity report card grades forchildren and youth: Results and analysis from 49 countries.Journal of Physical Activity and Health 15 (Suppl 2): S251-S273.

Centers for Disease Control and Prevention (CDC).Comprehensive School Physical Activity Programs. 2019.https://www.cdc.gov/healthyschools/professional_development/e-learning/cspap.html. Accessed July 2019.

Community Guide. 2019. The Guide to Community PreventiveServices https://www.thecommunityguide.org/topic/physical-activity. Accessed 18 January 2019.

Community Preventive Services Task Force. 2014. PhysicalActivity: Enhanced School-Based Physical Education.Community Guide.https://www.thecommunityguide.org/topic/physical-activity.Accessed 10 March 2019.

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PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.1.1, 1.4.1, 1.4.2, 2.1.1, 2.1.3, 2.2.1, 2.2.2, 2.2.3,3.4.2, 4.2.2, 4.5.3, 4.5.4, 6.2.1, 6.2.3, 6.4.1, 6.4.4

CHAPTER 13Behavioral and SocialApproaches to Understanding andPromoting Physical Activity

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The key behavioral theories and theoretical models usedto explain physical activity behavior

»  The definitions of behavioral and social approaches tophysical activity promotion

»  The rationale for promoting physical activity usingbehavioral and social approaches

»  Evidence-based strategies for behavioral and socialapproaches to physical activity promotion

»  Examples of each kind of evidence-based strategy

OPENING QUESTIONSAlmost everyone cycles in and out of being physically active.Some weeks are good; others are not. Weeks turn into months andthen into years. Life circumstances and demands have a way ofshifting priorities.

»  Has this ever happened to you? Have you had to change or stopan exercise routine because of life changes? How did you workthrough it? What strategies did you use to continue to makephysical activity a priority?

»  Has this ever happened to someone in your family, or a closefriend? What were the barriers for this person continuing tobe physically active?

»  Alternatively, have you ever wondered how someone can bephysically active day after day, year after year? Why arethese people successful?

Understanding the behavioral and social approaches as to whypeople are physically active, and consequently, to the promotion ofphysical activity itself, relies on individual-level strategies, skills forbehavior change and maintenance, and the structure of the socialenvironment (as opposed to the physical environment). Historically,much of the early scientific work in physical activity promotion usedindividual behavioral approaches. More recently, strategies targetingthe social environment of individuals have begun to emerge. Thesestrategies, with their roots in psychology, behavioral science, andsocial psychology, have helped identify the ways people improvemany health behaviors, not just physical activity.

BEHAVIORAL THEORIES AND THEORETICAL MODELS OFBEHAVIOR CHANGEBehavioral scientists rely on theories and theoretical models toexplain and predict health behaviors, and explain changes in thosebehaviors and their maintenance. These theories and theoreticalmodels are very important for understanding why some individualsare active and others are not, and for guiding individual-focusedprograms and promotion projects for physical activity. Suchtheoretical models typically are used to determine what can beexpected from helping individuals adopt the skills they need to beginor continue physical activity.

Five popular behavior theories and theoretical models that havebeen used to explain and predict the physical activity behavior ofindividuals are depicted in table 13.1. This table shows the name ofthe theory or model, key behavioral constructs that the theory ormodel seeks to modify or support, and a brief explanation of thetheory or model.

Although a complete treatment of each aspect of these theoriesand models is beyond the scope of this textbook, it is important to befamiliar with them and with the constructs they are designed toinfluence. One popular example, the transtheoretical model, ispresented here. Different scientists prefer different behavior changetheories or models. Unfortunately, no single theory or model hasbeen proven to excel in its ability to predict behavior change andmaintenance. Each has strengths and weaknesses based on thevarying effects of the physical and policy environment on individualbehavior. Chapter 14 provides a more in-depth discussion of the builtenvironmental and policy influences on physical activity behavior.

The transtheoretical model presents a behavioral continuum andaddresses how people may move along that continuum to helpdevelop ideas about how to change physical activity behavior.Fundamentally, a person is classified into one of five behavioralstage categories—from not being ready to change or begin physical

activity at all to maintaining that behavior for an extended period oftime. The idea behind the transtheoretical model is that knowingwhere a person is along the continuum of behavior change makes ittheoretically easier to understand how that person could increasephysical activity behavior and the processes through which thosechanges could occur. The transtheoretical model was first developedto explain smoking-cessation behavior, but it has been extrapolatedto other health behaviors. It is one of the more frequently usedmodels in physical activity intervention studies.

Table 13.1   Popular Behavioral Theories and Theoretical Modelsfor Physical Activity Behavior

Theory or modelKey behavioralconstructs Explanation

Health beliefmodel (Janz etal. 2002)

Perceivedsusceptibility,perceivedseverity,perceivedbenefits,perceivedbarriers, cuesto action,self-efficacy

People become physically active if theyfeel at risk for a negative health outcome(i.e., perceived susceptibility andseverity), expect that by being physicallyactive they will prevent that negativehealth outcome (i.e., perceived benefits),and believe that they can initiate andmaintain the physical activity (i.e.,perceived barriers, self- efficacy).

Theory ofreasonedaction/theory ofplanned behavior(Azjen 1991)

Attitudes,subjectivenorms,behavioralcontrol,behavioralintention

People’s intentions to be physicallyactive depend on their beliefs aboutphysical activity weighted by evaluationsof these beliefs (i.e., attitudes), thebeliefs of other people about physicalactivity weighted by the value attributedto these opinions (i.e., subjectivenorms), and the perceived ease ordifficulty of being physically active(i.e., perceived behavioral control).People who intend to become physicallyactive are likely to do so.

Social cognitivetheory (Bandura1986)

Reciprocaldeterminism,environment,outcomeexpectancies,observationallearning,reinforcement,self-efficacy

Reciprocal relationships exist among theenvironment, personal factors (e.g.,beliefs), and physical activity. Beliefs(i.e., outcome expectancies, self-efficacy) can influence actions, and viceversa. Beliefs are molded by structureswithin the social and physicalenvironment. Physical activity caninfluence the environment and isdetermined by that environment. Theseprocesses occur through observationallearning and reinforcement.

Self-determinationtheory (Ryan andDeci 2000)

Externalregulation,introjectedregulation,identifiedregulation,integratedregulation,intrinsicmotivation

Actions vary in the degree to which theyare volitional, without any externalinfluence. Motivation to be physicallyactive occurs along a continuum fromexternal regulation (i.e., rewards,others’ demands), to introjectedregulation (i.e., moral reasons), toidentified regulation (i.e., usefuloutcomes), to integrated regulation (i.e.,important for personal growth), tointrinsic motivation (i.e., mastery,enjoyment).

Transtheoreticalmodel (Prochaska

Stages ofmotivational

People progress through five stages ofchange on the way to being physically

and DiClemente1983)

readiness forchange,processes ofchange

active: precontemplation, contemplation,preparation, action, and maintenance.Processes of change are activities thatpeople use to move through the stages:consciousness raising (increasingawareness), dramatic relief (emotionalarousal), environmental reevaluation(social reappraisal), social liberation(environmental opportunities), self-reevaluation (self-reappraisal), stimuluscontrol (reengineering), helpingrelationship (supporting), counterconditioning (substituting), reinforcementmanagement (rewarding), and self-liberation (committing).

Adapted from Dunton et al. (2010).

FROM INDIVIDUALS TO POPULATIONSSocial and behavioral approaches to physical activitypromotion have historically and necessarily focused onchanging or maintaining the exercise behaviors ofindividuals. As we learned in the first part of thistextbook, public health focuses on populations and to alesser degree on individuals. Why then are behavioral andsocial approaches of interest if they focus on a person-by-person strategy? The answer is that we can learn asubstantial amount about how to change populations byunderstanding how individuals can (and do) change.Although behavioral and social approaches may not strictlybe recommended for population-wide changes in physicalactivity, they do provide a useful point at which to beginbecause populations are composed of individuals.Understanding the system dynamics that influenceindividual behavior changes on a population level becomesthe missing link.

A graphic description of the transtheoretical model as it relatesto physical activity is shown in figure 13.1. The continuum ofbehavior has five categories that are used to classify how prepared aperson is to change behavior, or motivational readiness. The first isprecontemplation, in which a person has not even thought about

becoming physically active or may be unaware of the importance ofbeing physically active. The second category, or stage, iscontemplation. Here, a person may be thinking about making achange to be physically active a short time in the future, and may beaware of the health benefits, but has not yet reached a tipping pointto make the behavior change. The third stage, preparation, is whena person has reached that tipping point and is making small changesin behavior (e.g., taking the stairs rather than the elevator). Supportfrom friends and family may also be needed as this new stage ofactivity begins. Action is the fourth stage of the transtheoreticalmodel. Here, a previously sedentary person has recently becomephysically active and is perhaps meeting the U.S. physical activityguidelines of 150 minutes per week of moderate-intensity physicalactivity. Finally, the maintenance stage indicates that a person hasbeen consistently active for at least six months.

Knowing people’s stages of readiness helps practitioners tailorbehavioral intervention programs to match those stages. Forexample, people in the preparation stage should be encouraged toaction by giving them more reasons to exercise and fewer reasons tobe sedentary. Strategies that are useful in the precontemplationstage include teaching about the health benefits of exercise, thereasons for being physically active, and how to meet the minimalphysical activity guidelines. People at this stage should also beeducated about the risks of being inactive. Clearly, these strategieswould be of little use to those in the preparation or action stagebecause they would have already acquired this knowledge.

Although strategies for behavior change may differ depending onthe stage, two overriding concepts that are relevant at each stage ofmotivational readiness are decisional balance and self-efficacy.Decisional balance refers to a person’s ability to weigh the pros andcons of being physically active and to take action based on thatassessment. Typically, the cons outweigh the pros in theprecontemplation and contemplation stages, whereas the prosshould outweigh the cons in the action and maintenance stages.

Figure 13.1   The transtheoretical model of health behavior change forphysical activity.Adapted from Marcus et al. (1992).

Self-efficacy in physical activity behavior refers to the confidenceor perceived ability that a person may have to be physically activeand deal with the external threats and barriers that could result inslowing, stopping, or reverting progress. Research has identifiedself-efficacy as a key construct of several of the health behaviortheories in table 13.1. Strategies at each stage of motivationalreadiness incorporate some form of skills training to grow self-efficacy for people to become physically active and to maintain thatbehavior.

Of course, a person may remain in one stage or another forextended periods of time, or may experience relapse as a result ofillness, lack of time, or other priorities. However, identifying theperson’s stage and implementing strategies for dealing with thereasons for relapse can prove successful.

What keeps us from being physically active? Lack of time is thenumber one reason people don’t exercise at levels recommended forhealth enhancement. Individually adapted behavior changeprograms for physical activity promotion frequently incorporatestrategies for helping people identify and overcome barriers. Barriersare the real or perceived factors that a person believes are in theway of being physically active or preventing increases in physicalactivity. Identifying barriers can help people prioritize physicalactivity. Once the barriers are identified, strategies can be developedto overcome them.

A short quiz that is useful in identifying barriers to physical activityis shown in form 13.1. Do any of these barriers apply to you? Whatstrategies might be useful in overcoming the barriers to help youmake physical activity a priority in your life?

SOCIAL SUPPORT FOR HEALTH BEHAVIOR CHANGERelated to, but distinct from, theories of behavior change is theconcept of social support. Social support in public health refers tothe degree to which people perceive that they are receivingassistance from their direct or indirect social network to overcomehealth challenges. Social support is thought to be key to promotingphysical activity, either by being integrated into the existing healthbehavior theories and models reviewed earlier, or as a stand-alonestrategy.

The concept of social support has been an important factor tounderstanding health behavior change and maintenance for years. Itstems from observations that people with shared experiences andgoals benefit from the support they receive from each other. Thissupport could be in many forms: two people who want to becomemore physically active and begin to walk together in the morningsbefore work; a husband supported by his wife to restart a physicalactivity program; or a mother who supports her child to be physicallyactive by enabling participation in a sport league after school. Eachof these examples constitutes some form of social support forphysical activity.

The three basic types of social support are perceived, received,and connected (Barrera 1986). Perceived support refers to theperception that one is adequately supported. For physical activity, anexample would be a woman who knows she can count on churchfriends to walk with her when she needs company. Received supportis more direct and measurable. It refers to the amount of directsupport a person can count on for physical activity.

An example of this is a basketball team that must have five membersto play. Each member counts on the others to be at the playgroundso the team can play. Finally, connected support refers to the degreeto which a person is socially integrated. Social integration providesimplicit social support as a result of the connections made throughparticipation. Examples are clubs, communities and communityevents such as fun runs, the workplace, and family and friends.Connected support is thought to be helpful in physical activitypromotion because of the experiences that can be shared through asocial network.

Behavioral and social approaches for physical activity promotionincrease physical activity either by enabling people with behaviorchange and management skills according to one of the healthbehavior theories or theoretical models in table 13.1, or bystructuring the social environment so that it is conducive to physicalactivity behavior. Behavioral approaches give people skills to bephysically active and to overcome barriers to implement those skills.Social approaches are one way to make it easier to use those skills.

Behavioral and social approaches increase physical activityparticipation as part of leisure, occupation, transportation, or at-homeactivities. Like informational approaches (discussed in chapter 11),behavioral and social approaches to increasing physical activity arebased on the theory that when people are told to engage in specifichealth behaviors that are generally perceived as being good for them(e.g., improving health), they will change their behavior.

INDIVIDUALLY ADAPTED HEALTH BEHAVIOR CHANGEPROGRAMSIndividually adapted behavior change programs integrate keycomponents of health behavior theories and theoretical models tohelp people change and maintain physical activity behaviors. Theevidence base behind these types of programs is strong, and thesestrategies work when implemented appropriately.

How physically active are your family members? Why are theyactive or inactive?

What kind of improvements can be expected in individuallyadapted behavior change programs? Substantial increases inphysical activity behavior have been documented for these programs(pretest to posttest measures) in the Community Guide (USDHHS2017). Increases in physical fitness ( O2max) and caloricexpenditure have also been documented using these kinds ofprograms. Although the studies measure physical activity in a varietyof ways and vary in length, such increases are impressive. For thephysical activity outcomes, participation in such a program could be

expected to help the person achieve the 150-minutes-per-week goalrecommended in the 2018 Physical Activity Guidelines for Americans(USDHHS 2018). Because they are not one-size-fits-all approaches,individually adapted behavior change strategies seem to work forboth women and men. Moreover, they can be adapted to a variety ofsettings, including worksites, communities, schools, and possiblyfamilies.

To be most successful, individually adapted behavior changeprograms tailor the type and dose of intervention to the individual’sneeds and preferences and take into account the local context andsocial environment (culture and social norms). As discussed earlier,this could be a stage-matched education curriculum for someone inthe precontemplation or contemplation stage if the transtheoreticalmodel is being used to guide the program development.Alternatively, another strategy could include a keen focus on how theperson interacts with his or her environment to become morephysically active, if social cognitive theory is guiding the program.The key point is that there are models and theories, but each type ofstrategy in individually adapted behavior change is guided by anemphasis on the needs of the individual and the individual’s needsfor success.

When considering how individually adapted behavior changestrategies could fit into a public health approach, it helps to identifyspecific examples. One such example of a promising individuallyadapted behavior change strategy, which could potentially be scaledup to reach a larger population, are mHealth strategies (medical andpublic health practice supported by mobile devices). Someresearchers are currently working on developing and testing tailoredsmartphone applications (apps) grounded on solid behavior changetheories, to match physical activity promotion strategies to thepersonality of each individual (King et al. 2016). Some people mayrespond to strategies that involve being social, working as part of ateam, or competing with other teams. Others may prefer approachesbased on the notion of self-management and self-regulation (e.g.,

using a fitness monitor to track daily activity levels). Finally, othersmay respond to strategies that optimize affect while being physicallyactive. Affect refers to how being physically active makes you feel.For some, that amazing feeling of scoring a goal (compared to theintent to stay physically fit) is what truly motivates them to bephysically active. Although this type of research is still in its earlyphases, the hope is that in the future, these type of strategies can bescaled up to reach many people around the world, and helpeveryone become and stay active in ways that work for them.

How do people change from being sedentary to being physicallyactive? Although there is no one way for everyone, behavioralscientists rely on strategies that increase self-efficacy and move aperson’s decision balance from more cons to more pros. Fivestrategies that are part of many individually adapted behavior changeprograms for physical activity promotion are shown in table 13.2.

Table 13.2   Behavioral Strategies Useful in Individually AdaptedBehavior Change Programs to Increase Physical Activity

StrategyIntendedconsequence Example

Substitution Stay physicallyactive when youmay not even bethinking aboutbeing active.

Push back from a desk during work andtake several two-minute walks duringthe day.

Social support(interpersonal)

Find a partner orpartners to helpyou stay active.

Join a walking club or exercise withfamily members.

Self-reward Provide positivefeedback toyourself for beingphysically active.

Set pedometer goals and reward yourselfwith a gift when short- and long-termgoals are reached.

Commitment Encourage tangiblecommitments foryourself to beingphysically active.

Sign a self-contract; become a physicalactivity support to someone who istrying to become more active.

Reminders Use promptingtools to remindyourself andothers aboutactivity.

Place exercise shoes and equipmentwhere they are visible (e.g., exercisemachines in the middle of the house orapartment instead of hidden in a backroom).

The art in this kind of work is finding the appropriate mix ofstrategies that will be most effective for the individual. Whereassome people need only simple reminders, others need several (orall) strategies to move into a physically active lifestyle.

SOCIOECOLOGICAL MODEL OF BEHAVIORIn addition to the traditional behavioral theories outlined in theprevious sections of this chapter, it is worth paying special attentionto more recent socioecological approaches to understanding healthbehaviors, including physical activity. While socioecological modelsof behavior are not as complex as full behavioral theories, theyprovide a conceptual framework and visual representation forunderstanding the multiple factors that influence physical activity,and therefore, potential solutions to encourage activity. Figure 13.2presents an adapted socio-ecological model for physical activity. Thebasic principle of socioecological approaches for understandinghealth behaviors is that although the behavior (e.g., exercising everymorning) occurs at the individual level, it is influenced by factors atmultiple levels, which in turn interact with each other. There aremany versions of the socioecological model of behavior available;some are very simple and some are very complex, but the principleof multiple levels of influence is the same across all.

Figure 13.2   Physical activity within different domains (leisure, transport,occupational, home) is influenced by different factors at each level.Adapted from Sallis et al. (2006).

For physical activity, the key levels of influence are the individuallevel, the interpersonal level, the social environment, the builtenvironment, and the policy environment. At the individual level, onemay ask: Is the person male or female? What is the person’s age?What is the education level of the person? All of these factors areknown to influence an individual’s propensity for being physicallyactive on a regular basis. The interpersonal level refers to the peoplethat one interacts with regularly, such as family, friends, classmates,or coworkers. The concept of social support, which was previouslydescribed, generally falls under the interpersonal level. However,there may be social support strategies aimed at a higher level ofinfluence: the social environment. The social environment differsfrom the interpersonal level because it refers to how society isorganized or how it behaves as a whole—beyond the people that wepersonally know or interact with in our daily lives. Examples of socialenvironment factors that can influence physical activity are the crimelevels of a neighborhood, the average income of residents in anarea, or the shared social values of a community. Some socialsupport interventions target a whole neighborhood or communityrather than specific individuals and their known social contacts(family and friends), and are therefore grounded in the social

environment level. The built and policy environments and theirinfluence on population levels of physical activity are explained inmore detail in chapter 14. Briefly, they refer to the physical featuresof urban or rural environments (e.g., roads, parks, public transit,pedestrian and bicycling infrastructure), and to the policies, laws, andregulations which can affect the opportunities for people to be active(e.g., speed limit regulations).

CASE STUDY

PROJECT ACTIVEThe transtheoretical model—combined with aspects ofsocial cognitive theory—was compared to a moretraditional model of exercise promotion in one of thefirst long term studies to examine the role ofindividually adapted behavior change in increasingphysical activity levels (Dunn et al. 1999). ProjectActive researchers recruited 235 sedentary women and mento participate in a two-year individually adaptedbehavior change program. These participants were betweenthe ages of 35 and 60, were not obese, and wereotherwise healthy (except for being sedentary).

The 235 participants were randomized into two groups.The structured exercise group received a standardexercise prescription encouraging them to become activeat a certain intensity (based on their baseline tests)for 20 to 60 minutes on three to five days each week.These participants were also given complimentary accessto a health club gymnasium for the first six months ofthe study. Finally, contact was maintained with them forthe full 24 months through newsletters and periodicmailings.

Participants in the lifestyle exercise group receivedan individually adapted behavior change program that

used the transtheoretical model to match their stages ofmotivational readiness with appropriate behavioralintervention strategies and processes. They attendedweekly meetings for the first four months of the programand then biweekly meetings for the next two months.These meetings focused on the cognitive and behavioralstrategies thought to help people make positive, lastingchanges. Each participant’s stage of motivationalreadiness was identified, and the strategies andprocesses used to increase knowledge and change behaviorwere matched to these stages. Topics covered in thesemeetings (among others) included how to set a goal andmonitor progress, how to reinforce positive behavior,how to overcome barriers that get in the way of beingphysically active (problem solving), how to build socialsupport, and how to prevent relapse.

The main outcome of interest in Project Active wasphysical activity (measured by estimated energyexpenditure) in the two groups. Would those in thelifestyle group increase their physical activity as aresult of the individually adapted behavior changeprogram? How would any change in the lifestyle groupcompare to that in the structured exercise group?

The main findings from Project Active are illustratedin figure 13.3. People in both groups significantlyincreased their physical activity levels from baselinethrough 24 months. Perhaps most interesting, the

lifestyle group showed a statistically equivalentincrease in energy expenditure from physical activitycompared to the structured exercise group. Similarfindings were seen for increases in aerobic fitness aswell. These results showed that not only is anindividually adapted behavior change program feasiblefor increasing physical activity among previouslysedentary people, but it can also be a usefulalternative for people who don’t prefer or don’t respondto more structured, traditional exercise prescriptionmodels. Can you think of some examples in which such amodel may not be the best choice? Project Activeconfirmed the utility of behavior change programs forphysical activity promotion.

Figure 13.3   Changes in energy expenditure (in kcal/kg per day) over24 months due to physical activity in Project Active.Data from Dunn et al. (1999).

Socioecological models of behavior are useful when consideringpublic health approaches for understanding and promoting physicalactivity. Addressing the problems occurring at the higher (or moredistal to the individual) levels of the socioecological model allows usto reach entire populations. However, the effect of strategiestargeting levels closer to the individual (inner circles) tend to begreater. This means that interpersonal or individual-level strategiesmay make a few people become much more active than previously,

while environmental strategies may make more people a little moreactive than previously. In an ideal scenario, a successful interventionwould target all levels of the socioecological model; however, this isobviously a very difficult task. At the very least, when considering theuse of individual or interpersonal strategies for physical activitypromotion, one should be well aware of the characteristics of thesocial, built, and policy environment contexts where theseinterventions will take place. In this way, an interpersonal orindividual strategy may help people overcome environmental barriersto be able to adopt and maintain an active lifestyle.

SOCIAL SUPPORT INTERVENTIONS IN COMMUNITYSETTINGS

Another recommended strategy for increasing physical activity viabehavioral and social approaches is social support interventions incommunity settings. Social support is a broad concept, but itgenerally refers to any strategy for developing or strengthening theinterpersonal connections or the social environment of people toencourage (or overcome barriers to) physical activity. Social supportcan be an important strategy in individually adapted behavior changeprograms, but the type of social support we refer to here is at thecommunity level, rather than interpersonal level only. Therefore, thistype of strategy operates in the social environment level of thesocioecological model of physical activity (figure 13.2).

Community social support interventions focus on changingphysical activity behavior by building, strengthening, and maintainingcohesive social networks in the community (i.e., beyond immediatefamily and friends) that provide supportive relationships for behaviorchange (e.g., a buddy system with neighbors, contracts with othersto complete specified levels of physical activity, and joining localwalking groups or other groups to provide friendship and support).Community social support interventions also often attempt toincrease social capital, which broadly refers to the factors thatcontribute to cohesive and well-functioning societies. Some elements

of high social capital include a shared sense of community, living inareas where you feel you can trust your neighbors or ask for theirhelp, being in a neighborhood where you can run into people andinteract with them informally, and trusting your elected officials.Creating a heightened sense of community and trust, and fosteringsocial interaction beyond an individual’s small social network, hasbeen linked to healthier communities at large.

Studies of community-based social support programs to promotephysical activity generally report the following findings (Kahn et al.2002):

Social support interventions in community settings increasephysical activity as measured in a variety of ways (e.g., blockswalked or flights of stairs climbed daily, frequency of attendingexercise sessions, minutes spent in physical activity).Time spent in physical activity can be expected to increase byan average of 44% above baseline levels.Frequency (days per week) of physical activity can be expectedto increase on average nearly 20%.More support (greater participation in social networks forphysical activity) may be associated with a higher level ofphysical activity. The potential for a dose-response relationshipbetween the two has not yet been demonstrated, however.Social support for physical activity promotion seems to beeffective in a variety of settings (e.g., communities, worksites,universities), for both sexes, across the adult age range, andamong people with various baseline physical activity levels (bothsedentary people and those who were already active).

Does social interaction promote participation in regularphysical activities?

In some recent studies with international settings, the findingshave suggested that among certain populations and contexts,fostering social interaction may be as important or more importantthan promoting exercise or sport (i.e., physical activity to becomehealthier versus physical activity to have fun and spend time withothers) (Salvo et al. 2017). Finding ways for people to be with eachother in public, informal settings may be more effective thanpromoting individual-level behavior change with the focus on health,in cities in Brazil, Columbia, or Mexico. Understanding one’s socialenvironment (social norm, culture, values) thus becomes extremelyimportant when designing successful physical activity interventionsbased on social support.

As with any community-based work, developing community-basedsocial support systems can be challenging. Whether it is a faith-based exercise program for one specific place of worship, aneighborhood walking club across several blocks, or a sport leaguein a parks and recreation department in a town or city, the mostimportant first step in developing such programs is to know the targetaudience. The most well-intentioned program will never get off the

ground unless leaders and stakeholders are consulted and theirideas are considered prior to program development. Chapter 15introduces the logic model and program evaluation strategies. A keyfirst step is defining the problem through census data, health surveydata, or other sources. And perhaps the most important step is toleverage existing networks and other sources of social support ratherthan trying to create new ones.

CASE STUDY

HEART AND SOUL PHYSICAL ACTIVITY PROGRAMPeterson and colleagues (2005) developed a uniquephysical activity program targeted at women in midlife(35 to 65 years of age) using churches as the targetcommunity and focusing on developing a social supportsystem. Physical activity was promoted through thechurch-based support network. The goal of the projectwas to increase moderate-intensity physical activityamong program participants compared to those in churchesnot receiving the program. Over a 12-week period,participants met for one hour each week and workedduring this time to identify and develop ways to supporteach other to be more physically active. During themeetings, participants were asked to share theirphysical activity goals, barriers, and successes withother members and group leaders. Strategies for findingoutside support (e.g., people to exercise with) wereincluded. Participants in the control churches receivedan exercise brochure, information regarding physicalactivity recommendations, and several follow-uptelephone calls during the 12-week session.

Although the study was fairly small, the participantsin the social support group demonstrated a 63% increasein the minutes per week spent in physical activity that

was at least of moderate intensity. Those in theinformation-only control group churches also increasedtheir minutes per week of moderate-intensity physicalactivity (by 43%), but not nearly as much as the socialsupport group. The authors of this study concluded thatthis type of social support–based physical activitypromotion showed some promise as a strategy to promotephysical activity.

A final note: Although individually adapted behavior changeprograms and community-based social support systems have beenscientifically shown to increase physical activity, other types of socialand behavioral strategies have not. This may be due to lack ofevidence (i.e., the strategy has not been rigorously tested) orbecause the strategy does not actually work. Of course, it isimportant to know what works, but it is also important to know whatdoesn’t work in physical activity promotion. Knowing the evidencebase allows for more informed decisions about physical activitypromotion programs. Clearly, programs for which there is evidence ofeffectiveness should take precedence.

According to the Community Guide (USDHHS 2017), social andbehavioral approaches to physical activity promotion which lackevidence to recommend their implementation include college-basedhealth, and classroom-based health education curricula forelementary, middle, and high school students. Additional behavioralapproaches that the updated version of the Community Guiderecommends to promote physical activity, but were not discussedextensively in this chapter, include enhanced school-based physicaleducation, and family-based interventions.

LEADER PROFILEMelody Ding, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?While I have always been passionate about exercise andsport, it was by accident that I got into this field ofresearch. I was interested in how the environmentinfluences human behavior, but when I was looking for aPhD advisor, I was fortunate to get an opportunity to workwith Jim Sallis before I knew very much about physicalactivity research at all.

Did any one person have a major influence on your career?How?I have a few to name. I can definitely “blame” my parentsfor my pursuit of an academic career; they got meinterested in science and physical activity at a young ageand supported me all the way. Professor Mel Hovell fromSan Diego State University was a great influence on mycareer: He believed in me from the start by offering me anopportunity to study in the United States while I wasstill an undergraduate student in marine biology in China.He intrigued me with the world of behavioral science somuch that I never wanted to leave. Professors Jim Sallisand Adrian Bauman, two brilliant researchers in physicalactivity, have had a substantial influence on the way Iapproach research. Mel, Jim, Adrian and others haveremained my lifelong mentors, collaborators and friends.Finally, the field of physical activity is full oftalented researchers, leaders, and thinkers who haveinspired me.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?

I enjoy the process of understanding physical activity byworking with people outside of physical activity. Forepidemiological research, I like considering physicalactivity as a core component of a constellation of healthbehaviors and understanding it within the context of theenvironments, circumstances, and lifestyles as a whole.For intervention and policy research, I am passionateabout aligning the agenda of physical activity promotionwith economic, social, and environmental cobenefits toadvocate for investments in physical activity with ongoingsocietal dividends. Out of all research translationstrategies, the one I use the most is communication. Ihave fond memories of speaking with peer-scientists,students, practitioners, policy makers, mass media, andthe public, and I have truly enjoyed these experiences.

Why do you do what you do?For passion, impact, and friendship. I am passionate aboutphysical activity and exercise in my personal life andwould love to help more people around the world enjoyphysical activity as much as I do. I strive for makingchanges in the real world, whether it is throughgenerating evidence, informing policies and guidelines,teaching and education, or communicating with the public.Finally, I have made wonderful friends and comrades in thephysical activity community and enjoy working togethertoward the same common goal.

What are two key issues that must be addressed by 2030?First, we need to drastically reduce our dependence ondriving by means of reform in urban planning andtransportation. We should reconsider how we travel andmake active and public transportation the default choice.

Second, I would really like to see girls and women beingas active as boys and men. We need to empower girls andwomen to take a leap forward, to embrace and enjoyphysical activity, particularly in their leisure time. Inmany parts of the world, this involves removing structuraland cultural barriers, creating safe environments, andproviding social support. We cannot achieve genderequality without giving boys and girls, and men and women,equal opportunities to be active.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

Behavioral and social approaches can improve readiness forindividual and community behavior change.The behavior theories and theoretical models highlighted intable 13.1 and the socioecological model of physical activityin figure 13.2, as well as other theories and models, helpexplain why people are physically active or inactive, and alsohelp to develop approaches for behavior change programs.Individually adapted health behavior change programs teachbehavioral skills such as goal setting and self-monitoring ofprogress toward those goals, building social support for newbehaviors, reinforcing behavior through self-reward andpositive talk, structured problem solving to maintain behaviorchange, and preventing relapse into sedentary behavior.Individually adapted health behavior change programs arerecommended to increase physical activity.Social support interventions focus on changing physicalactivity behavior through both interpersonal and socialenvironment strategies, like building, strengthening, andmaintaining social networks that provide supportiverelationships for behavior change; and by improving thesocial norm of a community to become more supportive ofactive lifestyles by residents.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in the

text. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYAjzen I. 1991. The theory of planned behavior. Organizational

Behavior and Human Decision Processes 50: 179-211.Bandura A. 1986. Social Foundations of Thought and Action.

Englewood Cliffs, NJ: Prentice Hall.Barrera M. 1986. Distinctions between social support concepts,

measures, and models. American Journal of CommunityPsychology 14: 413-445.

Dunn AL, Marcus BH, Kampert JB, Garcia ME, Kohl HW III, BlairSN. 1999. Comparison of lifestyle and structured interventionsto increase physical activity and cardio-respiratory fitness: Arandomized trial. Journal of the American Medical Association281: 327-334.

Dunton GF, Cousineau M, Reynolds KD. 2010. The intersection ofpublic policy and health behavior theory in the physical activityarena. Journal of Physical Activity and Health 7 (Suppl 21):S91-S96.

Janz NK, Champion VL, Strecher VJ. 2002. The health beliefmodel. In Glanz K, Lewis FM, Rimer BK, eds. Health Behaviorand Health Education. San Francisco: Jossey-Bass, 45-66.

Kahn EB, Ramsey LT, Brownson RG, et al. 2002. Theeffectiveness of interventions to increase physical activity.American Journal of Preventive Medicine 22: 73-107.

King AC, Hekler EB, Grieco LA, Winter SJ, Sheats JL, Buman MP,Banerjee B, Robinson TN, Cirimele J. 2016. Effects of threemotivationally targeted mobile device applications on initialphysical activity and sedentary behavior change in midlife andolder adults: A randomized trial. PLoS One 11 (6): e0156370.

Kohl HW III, Dunn AL, Marcus BH, Blair SN. 1998. A randomizedtrial of physical activity interventions. Medicine & Science inSports & Exercise 30: 275-283.

Marcus BH, Banspach SW, Lefebvre RC, Rossi JS, Carleton RA,Abrams DB. 1992. Using the stages of change model toincrease the adoption of physical activity among communityparticipants. American Journal of Health Promotion 6: 424-429.

Peterson JA, Yates BC, Atwood JR, Hertzog M. 2005. Effects of aphysical activity intervention for women. Western Journal ofNursing Research 27: 93-110.

Prochaska JO, DiClemente CC. 1983. Stages and processes ofself-change of smoking: Toward an integrative model ofchange. Journal of Consulting Clinical Psychology 51: 390-395.

Ryan RM, Deci EL. 2000. Self-determination theory and thefacilitation of intrinsic motivation, social development, and well-being. American Psychology 55: 68-78.

Sallis JF, Cervero RB, Ascher W, Henderson KA, Kraft MK, Kerr J.2006. An ecological approach to creating active livingcommunities. Annual Reviews of Public Health 27: 297-322.

Salvo D, Sarmiento OL, Reis RS, Hino AA, Bolivar MA, LemoinePD, Gonçalves PB, Pratt M. 2017. Where Latin Americans arephysically active, and why does it matter? Findings from theIPEN-adult study in Bogota, Colombia; Cuernavaca, Mexico;and Curitiba, Brazil. Preventive Medicine 103: S27-S33.

U.S. Department of Health and Human Services. 2017. WhatWorks Fact Sheet: Increasing Physical Activity. ResourceSummary (The Guide to Community Preventive Services).https://www.thecommunityguide.org/sites/default/files/assets/What-Works-Factsheet-PhysicalActivity.pdf. Accessed 25January 2018.

U.S. Department of Health and Human Services. 2018. PhysicalActivity Guidelines for Americans, 2nd ed. Washington, DC:U.S. Department of Health and Human Services.www.health.gov/paguidelines/second-edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.1.1, 1.1.5, 1.4.1, 1.4.2, 2.1.3, 2.3.3, 3.1.3, 3.1.4,3.3.1, 3.3.2, 3.3.3, 4.1.1, 4.1.2, 4.1.5, 4.2.5

CHAPTER 14Environmental and PolicyApproaches to PromotingPhysical Activity

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  How aspects of the built environment can promote orhinder physical activity

»  How enhancing access to neighborhood destinationspromotes physical activity

»  The role of urban design in physical activity promotion

»  The differences between micro-environmental (street-scale) and macro-environmental (community-scale) urbandesign, and how each can contribute to physical activitypromotion

»  How the built environmental characteristics that mayinfluence physical activity are measured

»  How physical activity is influenced by policies beyond thehealth sector, and how these policies are necessary toscale-up built environment strategies for physical activitypromotion

OPENING QUESTIONS»  What is the physical environment? What is the built

environment? What is the natural environment?

»  Can the built environment influence the levels of physicalactivity of populations? If so, which aspects of the builtenvironment contribute to physical activity? Which aspectshinder physical activity?

»  How can the local built environment be changed to increaseopportunities for physical activity at the population level?

»  What strategies aid in the development and implementation ofpolicies to promote active environments and active people?

What do you think of when you hear the term built environment?The apartment or home in which you live? The gym or fitness centerdownstairs? The buildings at your university? A hike and bike trail inthe center of town? How does the built environment differ from thephysical environment? Are they synonyms? Although these termsare often used interchangeably, they are not the same thing. Thephysical environment is a broad term encompassing all the physicalaspects of the environment that surround us. This can include thecity roads and lampposts, but also topographical aspects, such as

the steepness of a hill. There are two main types of physicalenvironment features: those of the built environment and those of thenatural environment. The built environment refers to any aspect ofthe environment, urban or rural, which has been created by people,such as sidewalks, roads, stoplights, crosswalks, buildings, andparks. In contrast, the natural environment refers to physical aspectsof the environment which were not created or altered by people. Asyou may expect, natural environment features are more common inrural rather than urban settings; however, urban settings may alsoinclude natural environment features. Some protected national parksare located within city limits and were created by people (whichwould fall under the built environment category), but the actualnatural resources have always been there. A river crossing a city ispart of the natural environment; however, a paved walking trailalongside that river would be a built environment feature. Theweather and wild animals are other aspects of the naturalenvironment. Urban green spaces can be composed of a mix of builtand natural environment features. In some parks all of the “naturalelements,” such as plants, trees, and lawns, were put in place bypeople, making them built environment features. However, othergreen urban spaces, such as national parks may be naturallyoccurring, thus making them a natural environment feature.

We have known for centuries that health is related to the physicalenvironment. In fact, at its origins, public health began by studyingthe ways in which the physical environment affects the health ofpopulations. Where you live matters. Although this can be (and is)related to factors of the social environment, physical environmentfactors also play an incredible role in determining health. The qualityof the water and air (natural environment), the type of housing (builtenvironment), roads (built environment), and other environmentalfactors are critical to overall health, health care, and diseaseprevention. However, the physical environment is rarely independentof the social environment within it. As we learned in chapter 13, alllevels of the socioecological model of behavior interact to influence

individual behavior. Within the realm of physical activity and publichealth, several elements of the physical environment— in particularsome key elements of the built environment—have been studiedextensively in recent decades. Substantial evidence links certainbuilt environment structures to the levels of physical activity of urbanpopulations. These structures can be positive (e.g., sidewalks orbicycle lanes), or negative (e.g., a high-speed six-lane road with nocrosswalks) in their influence on physical activity.

As covered in chapter 13, strategies for individually adaptedbehavior change and enhancing social support can increase physicalactivity among individuals. Although these strategies may besufficient for some people, public health is also interested in changesthat affect population health. Thus, physical activity and public healthshould also focus on changes that may affect an entire group ofpeople such as all the residents of a town, students enrolled in anurban school district, or the residents of an apartment complex.

How many parks are within one to two miles of your home? Arethey sufficiently maintained to encourage regular use forphysical activity? How could they be improved to support morephysical activity?

Environmental and policy change initiatives to improve publichealth seek to augment the approaches focused on individuals.Actions at the environmental and policy levels directly affectorganizations and physical structures rather than individuals, in anattempt to reach more people and achieve longer-term and moresustainable results. To maximize success, environmental and policychanges must involve many sectors of influence outside of healthdepartments. For example, building a bicycle lane on a major streetmust involve the transportation department, the city government, andpublic safety experts.

POLICY INFLUENCES ON HEALTH

Changing or maintaining a behavior is difficult whenexternal forces continue to work against the behavior.Effective health and health behavior policies includetobacco or sugar-sweetened beverage taxation, purchase agerestrictions to reduce smoking and alcohol consumption,water supply fluoridation to reduce dental caries, speedlimits and seat-belt laws to reduce motor vehiclefatalities, and breakaway bases in Little League Baseballto reduce musculoskeletal injuries in players. The fieldof public health differs from the medical and health carefields because it acts at the population level (ratherthan at the individual level) to prevent disease anddisability. Can you think of other examples of publichealth policies, and in particular, those that may impactthe physical activity levels of populations? When thinkingof these examples, keep in mind that health-enhancingphysical activity can occur within different domains(leisure-time, transportation, occupational, or home-based).

Major changes in public health rarely, if ever, depend solely onachieving behavior change in individuals. Policy initiatives,environmental initiatives, or both, usually facilitate individual behaviorchange. As shown in chapter 13, methods that target the higherlevels of the socioecologic model (i.e., the built environment or policylevel) usually reach many more people than those targeting theindividual or interpersonal level. Environmental and policyapproaches for physical activity promotion tend to focus on gettingmore people to become a little more active rather than getting a verysmall amount of individuals to become much more active. In thispublic health approach, small benefits for the majority of thepopulation are preferred over large benefits for only a small group ofindividuals.

Environmental and policy approaches to physical activitypromotion create or enhance opportunities, and support and promptpeople living in a common area (e.g., a neighborhood, a zip code, a

county, a city, a state, or a country) to be more physically active.These approaches are often combined with informational outreachactivities to enhance their effectiveness. Environmental and policyapproaches may involve making changes to the built environment,making changes in organizational norms and regulations, or enactinglegislation that improves health.

ACCESSBroadly defined, the term access refers to the ability to approach oruse something. The concept of access is central to understandingthe relationship of the built environment on physical activity, andunderstanding that the enhancement of the built environment is moreconducive to active lifestyles. In physical activity and public health,creating or enhancing access to places for physical activity is anevidence-based strategy for increasing physical activity.

There are several types of access that may impact one’s ability tolead a healthy lifestyle. Geographic access refers to the features ofthe built environment in a person’s neighborhood. Two ways ofassessing geographic access are with measures of availability (e.g.,the number of nearby parks or recreation), or of accessibility (theease of reaching a desired destination). To illustrate these examples,imagine that you have two neighborhood parks less than a mile fromyour home, and one of them is almost directly adjacent to yourbackyard. This means that you have high availability of parks in yourhome neighborhood. However, you live on a very long and windingcul-de-sac, and you must walk along a long road, without sidewalksin some places, for more than 40 minutes until you finally reach thepark entrance. In this scenario, accessibility is quite low. Bothavailability and accessibility are important components of geographicaccess to places for physical activity. In addition, there are otherdimensions of access beyond geographic access that may impactone’s ability to be physically activity, such as economic access. Nowimagine that you finally reach the park behind your backyard;however, you want to use their tennis courts—which charge a fee.

For you, this fee may be restrictive and may deter you from beingable to take advantage of this built environment neighborhoodresource. The economic domain of access falls under the policy levelof the socioecological model of behavior, and we will discuss it infurther detail later in this chapter.

Most studies that have examined the issue of increased accessfor physical activity have focused on strategies for changing the builtenvironment. Examples include converting an old rail bed to a hikeand bike trail, building a new playground, or unlocking the schoolplayground basketball court so that it can be used on weekends aspublic open space.

Although intuitive to some, the idea of creating or enhancingaccess to physical activity is not as straightforward as it seems.Simply clearing a new trail, cleaning up a park, building a new ballfield, or providing more exercise equipment in a fitness center maynot be enough. Most of the studies that have pointed to higherphysical activity participation with increased access to places inwhich to be active have also included some form of programming,also referred to as place activation. Essentially, it does not appearto be enough to build or provide easier access to built environmentresources that promote physical activity. Information and activitiesare necessary for people to learn about the existence of these newresources and to provide motivation to use them. For example, if apark has been cleaned up, a community campaign plus free exerciseclasses at the park on the weekends may get more people to takeadvantage of the newly improved resource.

In general, the physiological and behavioral results of studiesexamining increased access to places in which to be physicallyactive support it as a recommended strategy (Kahn et al. 2002).Caloric expenditure among participants may be expected to increasean average of just over 8% above baseline. The percentage ofpeople in a defined population exposed to increased access tophysical activity might be expected to increase physical activityparticipation around 3%. Cardiorespiratory fitness (aerobic capacity)

should increase more than 5% on average. Some participants willincrease much more, however, and others may not increase at all (ormay actually decrease). Results of effectiveness (increasedparticipation in physical activity) have been seen in various types ofsettings, in low-income communities, and in various racial or ethnicgroups. Men and women seem to respond equally well to increasingaccess to places in which to be physically active.

CAUSE AND EFFECT?One of the major challenges facing researchers in the areaof environmental and policy change for physical activitypromotion is the lack of true experiments. A trueexperiment involves an experimenter randomly assigning atreatment (e.g., a pill) to one group and a control orplacebo to another group, and measuring the subjects ineach group before and after. More comprehensiveexperiments are blinded, and subjects do not know whatpill they are receiving (treatment or placebo). It is verydifficult, and certainly not practical, to randomly assignpeople to a neighborhood that has an optimal builtenvironment for physical activity or to a neighborhoodthat doesn’t. People are free to live where they wish, soresearchers must measure what occurs withoutexperimentation. They cannot know whether characteristicsof the neighborhood make people more active, or whetherpeople who are already physically active or are lookingfor those characteristics are more likely to choose thatneighborhood. This issue can confound studies looking toassess whether the cause (a neighborhood more conducive tophysical activity) results in the effect (higher levels ofphysical activity participation). How would you design astudy to tackle this problem?

Access is a general yet critical concept when studying theinfluence of built environment features on physical activity, andalthough the focus has been on specific places meant forrecreational physical activity (e.g., parks, recreation centers, gyms),

the term access actually extends to any destination or place within aneighborhood or city. The accessibility of built environment featuresthat are not thought of as being typical physical activity resourceshave also been found to be conducive to more physical activity. Forexample, access to public transit infrastructure or to shops andrestaurants is associated with physical activity even though theseare not places where people go to do exercise or sport. When thesetypes of destinations are close to someone’s home, workplace, orschool, they promote physical activity because people can activelytravel to get there (i.e., by walking or bicycling, or in other words, bybeing physically active). Therefore, strategies to increase access tokey destinations for physical activity promotion should not be limitedto the places that people go to for exercise or sport. Increasinguseful (public transit), fun, and vibrant (shops, restaurants)destinations within walking distance of people’s homes orworkplaces is a way to promote transport-based physical activity.Similarly, it is important to understand the underlying socialenvironment where you are trying to increase physical activity byincreasing access to built environment resources. For example, inthe United States, research has shown that increasing access totraditional places for recreational physical activity (e.g., parks andrecreational centers) is an effective strategy for promoting physicalactivity (Kahn et al. 2002). In contrast, recent findings from Brazil,Colombia, and Mexico suggest that in Latin America, where socialinteraction is a much stronger cultural value than individual healthand wellness, increasing access to places that facilitate socialization(e.g., public squares) may be a more effective strategy for physicalactivity promotion (Salvo et al. 2017).

URBAN DESIGNIn the same way that access is not limited to destinations forrecreational physical activity, adding new places for physical activity(e.g., building more parks, adding transit stops) is not usuallysufficient for increasing access. There are several urban design

elements that are necessary for achieving appropriate and equitableaccess to optimal built environment resources. For the purposes ofthis text, urban design refers to the form, function, and outwardappearance of the built environment in defined entities, such asneighborhoods, towns, cities, and communities. How practical is it tohave new shops and restaurants within close distance if there are nosidewalks, bicycle lanes, or crosswalks in the neighborhood? In spiteof the increased availability of nearby destinations, it is unlikely thatsomeone would reach them via active travel if the urban design isnot supportive of physical activity. Therefore, the concepts of accessand urban design are codependent. Proper access to builtenvironment resources that affect physical activity (e.g., parks,shops, transit) is hard to achieve without a good underlying urbandesign.

STREET-SCALE OR MICRO-ENVIRONMENTAL URBAN DESIGNStreet-scale or micro-environmental urban design strategies topromote physical activity include changes to the built environment insmall geographic areas, generally limited to a few blocks. Someexamples of micro-environmental urban design elements which arerelevant for physical activity include sidewalk availability, quality(e.g., width, flatness), and features (e.g., shade, benches); bicyclelane availability, quality, and features; crosswalks; pedestrian islands;posted speed limits and signage; and the availability ofneighborhood traffic-calming devices. These approaches seek tomake specific street segments (blocks) more safe and amenable to avariety of physical activity opportunities. Some specific strategiesinclude marked crosswalks for pedestrians; traffic circles, stoplights,signs, and speed bumps for traffic-calming; the repair of brokenwindows and graffiti to increase safety and aesthetics; and improvedlighting and landscaping.

Although the street and its features tends to be the focus of manymicro-environmental urban design approaches, there are urbandesign elements beyond the street level that can be considered to be

on a micro-neighborhood environmental scale. Examples include thelandscape design of a park, aesthetic features of a public square,and recreation center design.

USING CITIZEN SCIENCE TO PROMOTE MICRO-ENVIRONMENTAL URBAN DESIGN IMPROVEMENTSFOR PHYSICAL ACTIVITYOne approach to improve the micro-environment which hasyielded positive results in the design of small urbanareas is the use of citizen science combined withcommunity-based participatory research. Researchers havedeveloped a process by which residents of a small (micro)area gather information about their local neighborhoodenvironment which either hinders or promotes their abilityto lead active lifestyles (i.e., they become “citizenscientists” as they collect data about theirneighborhood). Then they discuss these findings with eachother and prioritize themes, which are then presented tolocal stakeholders with the goal of negotiating someactions for improvements in the built environments (e.g.,adding a cross walk), and social environments (e.g.,implementing a neighborhood watch to prevent crime). Thisapproach has been used in a variety of diverse micro-neighborhood environments around the world, such as theSan Francisco Bay Area, Mexico, Colombia, Brazil, Chile,and Israel (King et al. 2016). In all settings, thisprocess has resulted in small urban design changes that ifscaled up, could contribute to helping populations becomemore physically active.

Studies examining street-scale or micro-environmentalcharacteristics and their relation to physical activity have used avariety of outcome measures. Researchers have looked at increasesin the number of walkers or bicyclists in a given area, thesignificance and change in prevalence of people who are physicallyactive, and the number of users of a walking and jogging path. The

varied outcome measures make summarizing the effects of street-scale changes difficult. All things considered, a 35% averageincrease in physical activity might be anticipated with appropriatestreet-level changes (CDC 2011). The types of changes necessaryclearly depend on the neighborhood that is targeted, and because notwo are alike, the general recommendation can encompass manyspecific strategies.

CASE STUDY

BOGOTÁ, COLOMBIAGomez and colleagues (2010) reported on efforts in thecapital city of Bogotá, Colombia, to remake the citycenter and outlying areas to increase the mobility ofcitizens and recover public space to enhance the qualityof life in the city. Many of these changes involvedcommunity-scale improvements in land use policies andurban design strategies. A large, modern mass transitsystem was created to reduce motor vehicle traffic andair pollution, green space and parks were created, and

bicycle paths (ciclorutas) were constructed to connectthe parks. The remaking of Bogotá has been one of themost substantial urban redesign efforts ever undertaken.

The authors studied the role these changes may havehad on physical activity participation. Using geographicinformation system (GIS) techniques (described in moredetail later in this chapter), the study mapped theneighborhoods in which participants (men and women ages18 to 65) lived, and the researchers analyzed theparticipants’ proximity to major community-level builtor physical environment elements that may be related tophysical activity participation. They consideredneighborhood density, land use mix, the density of

parks, the completeness of ciclorutas, the proximity totransit stations, and the topographic slope ofneighborhoods (Bogotá is situated on a plateau in amountainous area).

Results suggested that active people were more thantwice as likely to live in neighborhoods with thehighest density of parks compared to inactive people,and those who lived closer to a new bus or rapid transitstation were 27% more likely to be physically activethan similar residents who lived farther away. Althoughcausality is difficult to determine with this studydesign, it is clear that community-level built andphysical environmental variables are associated withincreased levels of physical activity.

Although micro-scale approaches can be scaled up to becomecommunity- or city-wide, they are most often initiated in smallneighborhoods in which leaders are looking to improve residents’livability and quality of life.

COMMUNITY-SCALE OR MACRO-ENVIRONMENTAL URBAN DESIGNCommunity-scale or macro-environmental urban design strategiesfor promoting physical activity involve changes and enhancements tothe built environment of urban areas of several square miles (orkilometers) or larger, which are usually defined as being anadministrative unit (zip code, neighborhood, school district, city, orcounty). These kinds of approaches strive to make entirecommunities more amenable to physical activity, whether that activityis transportation-related or exercise performed in discretionary time.Strategies at this level of influence include connecting transportationarteries; creating landscaping and lighting to enhance the aestheticsand perceived safety of the entire community; building a large-scaleand interconnected network of sidewalks, bicycle lanes, and trails;and designing new mixed-use residential areas so that destinationssuch as workplaces, schools, and areas for leisure and recreationare within safe walking or bicycling distances.

CASE STUDY

DEVELOPMENT AND PROMOTION OF WALKING TRAILSBrownson and colleagues (2004) reported the results ofan effort to increase access to walking trails in thestate of Missouri in the United States. Adults 18 yearsof age and older were targeted. The study group wasmostly women (75%), most had less than a high schooleducation (60%), and 70% were Caucasian. Control groupswere selected from similar communities in theneighboring states of Arkansas and Tennessee. Theprogram was designed to increase the physical activitylevels in rural communities, in part, by creatingwalking trails. Participants received eight individuallytailored newsletters to promote interpersonal activitiesand social support, while advertising community-wideevents such as walk-a-thons and walking clubs. Thewalking trails in the intervention were equipped withtracking systems to help people acquire individuallytailored walking reports. The cost of trail developmentwas approximately $3,000 (USD) per trail (six trailsfrom 0.13 to 2.38 miles, or 0.3 to 3.8 kilometers, inlength). Changes in the use of the walking trails andwalking behaviors in general (minutes per week) were ofparticular interest.

After a one-year promotion effort in six communities,changes in walking trail use and walking behavior wereobserved in this study. However, these changes werelimited to increases in trail use among those whoalready had been using the trails at the baseline or asthey were built. In other words, there was an increasein use among people who had already reported using thetrails. Although this is a positive result, the programseemed to miss affecting those who hadn’t used thetrails prior to the study. Certain demographic subgroupsshowed increases in weekly walking participation, but a

change was not observed in the population as a whole.The authors concluded that this method of increasingaccess in rural communities should be used to understandhow to design future studies in this area.

One important and unique macro-environmental urban designelement is road connectivity. The concept of connectivity refers tothe ease of getting from one place to another within a neighborhoodusing the city’s road network to walk or bike. If city thoroughfaresfollow a grid pattern, it is easy to use the street network (assumingsidewalks or bicycle lanes are available) to move around on foot oron bicycle; however, if intersections are very far from each other orthere are quite a few dead-end streets or culs-de-sac, connectivity isconsidered to be sub-optimal. Another related construct for themacro-environment that has emerged in the past couple of decadesis walkability. Walkability refers to the conduciveness of walking fortransportation based on features of the built environment of an urbanarea. Many researchers have proposed different definitions ofwalkability, using scores or indices. Some of these scores are evenused by real-estate companies to provide their clients withinformation about potential neighborhoods. High walkability scores orindices could indicate the best mix of built environment elements,and if optimized, could point to a neighborhood that is very easy tonavigate on foot. Likewise, neighborhoods with low walkabilityscores are those with suboptimal conditions for transport-basedwalking. Most available walkability scores or indices includemeasures of connectivity, land-use mix, and residential density,which are three critical components for optimal urban design thatpromote walking for transportation in an area. Although this definitionfor walkability is valid in many parts of the world, it is not applicablein others (e.g., Mexico or China) (Salvo et al. 2014; Lu et al. 2017).Therefore, it is always important to consider the local context,including the social environment (social norms and cultural values),

when trying to promote walkable environments because these maylook different in other parts of the world.

Studies examining community-scale changes for physical activitypromotion have used a wide variety of outcome measures (Heath etal. 2006). Some have studied the absolute number of walking trips ina community over a given time period; others, the distance of thosetrips, minutes of walking per week, and number of pedestrians in acertain area. Although these outcomes are not entirely comparable,the general interpretation is that making the built environment moreactivity-friendly can improve levels of physical activity (regardless ofhow it is measured) by an average of more than 160%. Clearly, thisis a major influence on physical activity habits in a community.

MEASURING THE BUILT ENVIRONMENTMeasuring the built environment is a challenge. As covered inchapter 4, there are a variety of ways to assess physical activitybehaviors and energy expenditure in individuals. Despite thelimitations discussed there, we are able to reasonably and accuratelyassess physical activity in individuals, and reliably separate thosewho are most active from those who are inactive or somewhatactive. We can reasonably assess and classify those who aremeeting or exceeding physical activity guidelines (U.S. Departmentof Health and Human Services [USDHHS], Physical ActivityGuidelines Advisory Committee [PAGAC] 2018). We can also identifythe context and types of physical activity being done. Although thereis much room for improvement, these methods have evolved andprogressed over the years.

Because of the significance of the built environment in physicalactivity promotion, it must be measured, and measured well, if weare going to further our understanding in this important area.Unfortunately, this is a much less developed area of research thanthat of physical activity in individuals. Due to the relatively recentattention given to the built environment, this is to be expected; newmethods and techniques are sure to continue to be developed.

Brownson and colleagues (2009) published a comprehensivereview of tools and techniques that have been used to measure thebuilt environment. They developed a categorization scheme thatconveniently separates existing tools into three broad categories:self-reported measures of perceptions of the environment, directobservation techniques (audits), and secondary analysis techniquesusing existing datasets and geographic information systems (GIS).

Self-report techniques are used to query study participantsregarding their perceptions of environmental supports of physicalactivity or barriers to physical activity. Most existing scientificevidence of an environmental effect on physical activity behaviorscomes from studies relying on self-reports of perceptions of theenvironment. Such tools are typically administered in an interview(on the telephone or face-to-face), on the Internet, or via mail survey.These questionnaires typically assess perceived aspects of access;community-scale and street-scale characteristics such as traffic,aesthetics, urban design, and safety and crime; and the availabilityof local physical activity resources.

Self-report tools can be useful because most are relativelyinexpensive to administer and can be used in large populationstudies; however, a respondent’s perceptions of the environmentmay or may not be consistent with reality. Respondents may over- orunderestimate aspects of the environment based on their personalsituation or health status. For example, someone who is rarelyoutside may not be aware of the environmental supports of physicalactivity and barriers to physical activity. Or less healthy people maynot see the same things that their healthier neighbors see. Theperception of crime is also a key issue. Studies suggest thatperceptions of crime in neighborhoods do not match the reality ofobjective crime statistics. However, it is now known that both theperceptions as well as the reality of the neighborhood environmentare important factors for understanding a person’s patterns ofphysical activity. Even if a neighborhood has sufficient builtenvironment resources for physical activity, if a person perceives it

as not being supportive of an active lifestyle, it is likely that personwon’t take advantage of their neighborhood’s objectives for activity-friendliness. For this reason, it is important, if possible, to combineself-report with objective measures of the built environment for amore comprehensive assessment.

WHAT IS A NEIGHBORHOOD?Studies relying on self-report often ask respondents todescribe the physical activity resources in theirneighborhoods. Unfortunately, there is not uniformagreement among scientists as to what exactly constitutesa neighborhood. A half-mile radius (approximately a ten-minute walk)? A one-mile radius (approximately a twenty-minute walk)? One’s zip code? Further, people’sperceptions of what constitutes their own neighborhoodsalso vary. To some, it is a few blocks around their home;to others, it extends to the first major avenue; and stillothers consider their apartment complex theirneighborhood. Obviously, this variability injectssubstantial uncertainty into assessment techniques and canmake comparisons among studies very difficult. What do youconsider your neighborhood to be? Do you know what kindsof physical activity opportunities are available there?

To minimize the biases that can result from self-reports, scientistsand planners often use more objective measures of assessmentcalled audits. Audits are based on direct observation of the builtenvironment of an area, and use inventories to quantify features ofthe community and street levels that can be observed, such as theexistence and condition of sidewalks, noise and traffic levels, thepresence of abandoned or unsafe buildings, and the cleanliness andusability of parks and park equipment. The results of these auditscan be used for research, to change and improve the environment,or both.

Audit tools can be particularly useful when collecting data that aremore standardized and not prone to respondent bias. Audits areusually more expensive to administer than self-report tools becauseof the personnel needed to collect and enter data for analysis andinterpretation. Training personnel to collect audit data is crucial, as isreducing the variability of observations by standardizing terms andobservation techniques. If a study is large, ongoing training and errorchecking of observers may also be required.

Geographic information systems (GIS) offer a third techniquefor assessing the environment. GIS are computational mappingmethods that assist in analyzing geographic and social data (e.g.,distances, landmarks, density, traffic, crime, resources, green space)by overlaying data in map format from multiple sources. Although thedetails of this technique are beyond the scope of this text, suffice it tosay that GIS is an objective technique that allows multiple inputsfrom secondary data sources. With available computing power, GIStechniques have grown in popularity allowing desktop analyses ofcomplicated geospatial datasets.

By using objectively derived datasets containing measures of thebuilt environment, researchers and planners can use GIS to identifybarriers to and supports of physical activity and relate the presenceof those barriers and supports to physical activity levels in acommunity. GIS is most useful when large areas are underconsideration and audits are not feasible because of costs andlogistical difficulties.

Because GIS techniques rely on existing datasets that have beenassembled for purposes other than research, the datasets maysuffer from incompleteness or errors. These problems can presentchallenges when analysts attempt to relate the exposure data (e.g.,neighborhood density) to the prevalence of physical activity in ageographically defined area. These challenges notwithstanding, GISoffers a tremendous resource that has yet to be fully explored forassessing aspects of the built environment as they may relate tophysical activity behaviors. A recent study of 17 cities in 12 countries

of the world, the International Physical Activity Environment Network(IPEN) study, developed detailed protocols for generatingstandardized and comparable GIS measures of the built environmentusing secondary data from very diverse settings of the world (Kerr etal. 2013; Adams et al. 2014; Sallis et al. 2016).

How walkable is your neighborhood? Would you walk more if itwas easier?

PHYSICAL ACTIVITY POLICYPhysical activity policy can be defined as legislative or regulatoryaction, including formal and informal rules that are implied or explicit,that is instituted by an organization with the power to support orinhibit physical activity participation. Such organizations includegovernments at all levels, nongovernmental agencies (includingemployers, schools, and places of worship), and less defined groupssuch as neighborhood associations and social groups. Most, if notall, environmental approaches to physical activity promotion mustresult from some kind of policy change, so it is very hard toimplement a meaningful small- or large-scale change to the builtenvironment (e.g., adding a sidewalk to a road) without policy-levelapproval. The environmental approaches (as reviewed in this

chapter) then influence physical activity behavior, which in turnaffects the health of individuals and populations.

According to Schmid and colleagues (2006), three broadclassifications of policies can influence physical activity positively ornegatively (i.e., encourage or discourage physical activity throughenvironmental changes, supports, or barriers).

First, policies can include formal written codes, regulations, orcourt decisions that carry legal authority. One example is city codesthat require a certain distance of building setback from a street toaccommodate sidewalks and pedestrian traffic; another is a directivethat all new roads must include sidewalks and bicycle lanes (e.g.,Amsterdam in the Netherlands); and finally, a state legislativemandate for providing daily physical education to elementary schoolchildren is another example of a formal written regulation.

There are some policies which do not directly impact the builtenvironment, but instead impact the ability and way in which peopleuse the built environment. For example, a university campus mayprovide free public transit passes to all their faculty, staff, andstudents. This may promote more active travel (walking to and fromtransit stations) and inhibit sedentary travel (via car), improvingeconomic access to a built environment resource (public transitinfrastructure). So, even though it is not physically impacting theenvironment—it does affect how people interact with it.

INCREASING ACCESS TO PHYSICAL ACTIVITY AT AWORKSITE

Provide secure and covered parking for bicycles to

encourage bicycling to and from work.

Install employee shower facilities and changing

rooms.

Provide financial incentives for active commuting to

work or for using public transit (e.g., free transit

passes to encourage walking to and from transit

stops).

Create a culture of physical activity by encouraging

brief exercise breaks throughout the workday.

Provide on-site fitness facilities or buildings that

are conducive to physical activity, as well as easy

access to walking and running routes; distribute

walking maps.

Offer reduced-fee fitness or recreation center

memberships to employees and their families.

Encourage employees to participate in community-based

worksite exercise competitions or community-based

mass participation events.

Nonlegal, but accepted and written, standards are a second typeof policy that may influence physical activity participation. The keydifference between these types of policies and the legally bindingones is that these are not usually mandated. As a result of traditionor professional standards (e.g., urban planning, architecture, orengineering), these types of policies become standards of practiceand can be used to encourage or impede physical activityparticipation.

Finally, unwritten social norms can also influence physical activitypolicy. More difficult to quantify, these are usually based in theculture of an organization or society and have the ability to influencephysical activity in a variety of ways. Social groups in which mostmembers value exercise and regularly participate may encouragenew members to be physically active (i.e., social support). A worksiteculture that encourages physical activity participation throughinformal walking groups is another example of unwritten socialnorms.

A stepped approach is necessary for understanding theeffectiveness of physical activity policy. Further, physical activity

policy can occur at multiple levels, in multiple types of organizations,and in multiple geographic settings. Figure 14.1 illustrates this three-dimensional matrix.

Figure 14.1   Physical activity policy matrix.Adapted from Schmid et al. (2006).

On the left side of the matrix is the stepped approach. Beginningat the bottom, a policy is first identified as encouraging or inhibitingphysical activity. Next, the determinants of that policy are identified.For example, why are certain city zoning codes in place that requireculs-de-sac instead of grid-type connected streets? Next, the degreeof policy implementation is of interest. How completely is themandate being followed? Are there consequences for not followingthe policy? For example, does a school district conduct annualfitness testing of all students if a state law requires it, but suffers noconsequences if it is not completed? Finally, what are the outcomesof the policy? Does it influence physical activity behavior? Does itimpede it? Along the bottom of the three-dimensional policy matrixare the various sectors in which physical activity policies can be

implemented. Each policy type (legal, written or unwritten practicesor standards, and unwritten norms) has roles in various sectors. Forexample, legal policies may address public spaces, transportation,and schools. Unwritten practices can be prominent in worksites andthe health sector (e.g., physicians’ offices and hospitals). Socialnorms can be prominent in private spaces such as places ofworship.

CHANGEABILITY?Clearly, macro-environmental level and policy changes toimprove the built environment of cities cannot happenovernight, or even in the span of a few years. Thesestructural types of changes require a long-term view andstrong leadership given that physical activity and healthbenefits may not be seen for many years or decades.Because these are expensive propositions, communityleaders must consider the financial impacts. Politicalchallenges can slow such changes as well—not allstakeholders may be supportive of broad policy andcommunity-level changes, but despite such difficulties,the long view is necessary. Perhaps the most relevant

question is, Can we afford to not make these changes forthe sake of the health of our citizens? Some cities aroundthe world, backed by their citizens and leaders, havebegun to execute bold moves toward healthier, more active,and more equitable cities for all. Examples includeParis’s ambitious plan to remove all cars from the citycenter within the next few years, Amsterdam’s heavyinvestment on bicycling infrastructure, and Mexico City’slarge-scale publicly operated bicycle-sharing program.

Finally, each policy type can operate at various levels of influence—local, state, regional, national, or international. Any cell in this four-by-six-by-five matrix can (theoretically) be isolated and examined forpolicies and policy determinants that may be used to affect the

environmental supports of or impediments to physical activity. Canyou think of examples in one of the cells?

LAND USE POLICYPerhaps the most relevant factor of the built environment as it relatesto physical activity is land use, which is directly affected by policies.Land use policies refer to the management, planning, anddevelopment of land in defined jurisdictions. Land use policies mostfrequently occur at the local level to advance the well-being of thecommunities that control the land. Zoning is another commonly usedterm that is synonymous with legislatively determined land usepolicy. Examples of land use strategies for physical activity includesetting density targets (i.e., creating guidelines about the number ofresidents per square mile) for a neighborhood, green spacemandates (e.g., preservation of undeveloped land) within town orvillage limits, and urban mixed-use developments that providedestinations within walkable distances to living spaces.

It is extremely difficult to implement access strategies aimed atproviding new or different types of neighborhood destinations withouta base land use policy which supports those changes. For example,it would be impossible to place a new park in a neighborhood if thecurrent land use code doesn’t allow it. It would be similarly difficult toadd a new public transit route, or more shops and restaurants, to anarea designated as being exclusively residential (as compared tocommercial or mixed-use designations).

Although no evidence-based formula for the perfect, or evenoptimal, set of land use policies exists that will maximize physicalactivity, many strategies have been shown to work in communities.Ongoing research will help us to identify specific approaches.

CASE STUDY

MUELLERThe Mueller neighborhood in Austin, Texas, was built onthe site of a municipal airport that dated back to theearly years of aviation and was closed in 1999. As partof a redevelopment effort, over 800 acres weretransformed into a new urbanist-inspired neighborhood.New urbanism is a neighborhood planning approach thatcreates sustainable communities by adhering to sixprinciples: walkability (pedestrian-friendly streetdesign), connectivity (interconnected street grid), adiverse and mixed-use built environment (shops, offices,and residences all in a geographically convenient area),mixed housing (a variety of housing choices),aesthetically pleasing and high-quality architecture,and public spaces in the neighborhood. Walking trails,parks, traffic-calming devices, sidewalks, bicyclelanes, and other strategies are hallmarks of the Muellerneighborhood design.

The development of Mueller offered a uniqueopportunity to study the effects of the street-scaledesign on physical activity participation. Although itwas not possible to experimentally assign people to theneighborhood, a natural experiment was possible. Caliseand colleagues (2012) surveyed newly arrived residentsin Mueller about their physical activity habits beforeand after their move to the neighborhood. The hypothesiswas that people who were less active in their previousneighborhoods would have higher reported physicalactivity levels in Mueller. The design of theneighborhood might be one explanation for any changesobserved.

Key results of the study are shown in figure 14.2.After moving to Mueller, study participants reported anaverage of nearly 30 additional minutes of moderate-intensity and vigorous-intensity physical activity eachweek compared to when they lived in their previousneighborhoods. Interestingly, there was an increase in

reported recreational walking (about 45 additionalminutes each week) after the move to Mueller, but there

was actually a decrease in reported walking outside theneighborhood (approximately 20 fewer minutes each week).The vast majority of the increase was in minutes perweek of walking within Mueller. The authors concludedthat the design characteristics of the neighborhoodseemed to influence physical activity behaviors.

Figure 14.2   Changes in reported physical activity after moving to aneighborhood supportive of physical activity.Adapted from Calise et al. (2012).

LEADER PROFILENicolas Aguilar, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?In my professional training, I realized that this fieldheld the largest body of evidence in relation to theprevention of different diseases and their treatments.However, there was a huge gap in this specialty becausethe training of health professionals was very poor andvery few public programs addressed the problem seriously.Therefore after finishing my physiotherapy degree in Chileand working in the public health system, I applied for ascholarship and moved to Australia to completepostgraduate studies in order to push for solutions tothis issue in my country.

Did any one person have a major influence on your career?How?When I was completing studies in the Master of ClinicalExercise Physiology program, I was lucky enough to meetWendy Brown. After sharing my expectations and futuregoals for my country and region, she invited me toundertake PhD studies under her supervision. I cannot bemore grateful for her guidance and the time she investedin my professional training. Her leadership and ability totrust the decisions of her team was remarkable, and Iadmired how she simplified complicated problems andprovided enriching feedback during that process. Despitebeing back in Chile, she has always been willing to helpand believes that we can make a global change.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?

A critical topic is capacity building (i.e., the processof developing knowledge and skills among individuals andorganizations to carry out self-sustained public healthresearch and practice in their own settings) in this areain Chile and Latin America; therefore, much of my effortis focused on this. Also, I am interested in increasingand developing evidence to identify population inequitiesin physical activity in an effort to reduce these gaps,while continuing to promote more active populations. Thecurrent efforts focus on identifying effective strategiesand good practices to be able to adapt and apply them inthe Latin American context. In addition, I activelyparticipate in community and advocacy activities becausethe demands for change are great, but science (andfunding) moves slower than these needs.

Why do you do what you do?I believe that we can change our world with the help ofthe sciences, but we need more communication and moreeffective ways to translate our findings. Physicalactivity is reflected in almost all things, especially insocietal inequities. If we contribute to more equitablesocieties, we will have more active societies and viceversa. Many scientific articles conclude that theirfindings will be useful for public policies and willbetter inform decision makers. I believe that now is thetime to actively participate in the design of publicpolicies and to become part of the decision-makingprocess. Our populations cannot keep waiting.

What are two key issues that must be addressed by 2030?We should report evidence that can be used by differentsectors and be able to effect positive changes inenvironments that promote good quality of life, in termsof encouraging more active lives and more inclusive andaccessible spaces.

Many countries are suffering from the consequences ofglobal warming. Therefore, the inclusion of more activemodes of transport and the protection of green spacesshould be crucial government priorities. We need to moveforward with these decisions before it is too late.

CO-BENEFITS OF ACTIVITY-PROMOTING ENVIRONMENTSAND POLICIESOften overlooked, but very relevant, are the effects that macro-environmental changes can have on factors outside of physicalactivity. In fact, strategies that are considered “physical activity policyand environmental interventions” are often motivated by entirelydifferent factors than the promotion of physical activity and health.Some examples include plans to improve mobility and reducecongestion in large cities (e.g., implementation of modern masstransit systems, or large-scale bicycle sharing programs); strategiesto improve social equity (e.g., Ciclovia in Latin America, known in theUnited States as “open streets,” where large portions of the roadnetwork are closed to traffic on Sundays for cyclists and pedestriansto use for recreation, providing access to other parts of town to non-car owners); strategies to mitigate pollution (e.g., no drive days); andmany others.

Another example of the co-benefits of physical activity promotionis how various studies have reported higher rates of socialinteraction and social capital (i.e., trust and cohesiveness among acommunity) in neighborhoods that encourage physical activity.People in these neighborhoods have a greater sense of community,or belonging, when compared to those living in other neighborhoods.Some studies have even reported lower crime rates, which may bedue to the implementation of physical activity promotion strategies.

Although these additional benefits to the implementation ofphysical activity promotion strategies (e.g., improving mobility andreducing congestion in large cities, or improving social equity) arenot always guaranteed, they are helpful arguments that can supportadvocacy efforts for investing in more physical activity–friendlycommunities. This is especially true nowadays, given the globalchallenges that we are facing (e.g., economic instability, climatechange), and the United Nation’s Sustainable Development Goalswhich highlight the need for more sustainable, equitable cities and

environments (UN SDGs, 2015). Knowing that in essence, asustainable city is an activity-friendly city, we must seize theopportunity to simultaneously tackle the challenges of physicalinactivity as well as those of urbanization, pollution, traffic,inequalities, and climate change, through joint solutions.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

Environmental and policy approaches may involve changingthe built environment; changing organizational norms andpolicies; or enacting laws or legislation that affect publichealth professionals, community organizations, legislators,departments of parks and recreation, transportationdepartments, planning commissions, and the media.Creating or enhancing access to key neighborhooddestinations like parks, shops and restaurants, and publictransit, combined with place activation efforts, involves theefforts of worksites, coalitions, agencies, and communities.Urban planners, architects, engineers, developers, and publichealth professionals use community-scale or macro-environmental urban design and land use policies andpractices to change the physical environment of large urbanareas to promote physical activity.Urban planners, architects, engineers, developers, and publichealth professionals use street-scale or micro-environmentalurban design and land use policies and practices to changethe physical environment of small geographic areas,generally limited to a few blocks, to promote physical activity.The three categories of measures of the built environmentare self-reported perceptions, objective audits, andgeographic information systems (GIS). Each has strengthsand weaknesses, and all are evolving.

Understanding the determinants and outcomes related topolicies that may support or inhibit environmental influenceson physical activity is important.Policies can be formal (i.e., legal) or informal (i.e., based ontradition or social norms).Policies that support or impede physical activity can occur inmultiple sectors and at multiple levels of influence.Understanding the intersection is important in determininghow to change policies to support physical activity.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYAdams MA, Frank LD, Schipperijn J, et al. 2014. International

variation in neighborhood walkability, transit, and recreationenvironments using geographic information systems: The IPENadult study. International Journal of Health Geographics 13 (1):43.

Brownson R, Baker EA, Boyd RL, Calto NM, Duggan K,Housemann RA, Kreuter MW, Mitchell T, Motton F, Pulley C,Schmid T, Walton D. 2004. A community-based approach topromoting walking in rural areas. American Journal ofPreventive Medicine 27: 28-34.

Brownson R, Hoehner CM, Day K, Forsyth A, Sallis JF. 2009.Measuring the built environment for physical activity: State of

the science. American Journal of Preventive Medicine 36 (4Suppl): S99-S123.

Calise TV, Dumith SC, Dejong W, Kohl HW III. 2012. The effect ofa neighborhood built environment on physical activitybehaviors. Journal of Physical Activity and Health 9 (8): 1089-1097.

Centers for Disease Control and Prevention. (2011). Strategies toprevent obesity and other chronic diseases: The CDC guide tostrategies to increase physical activity in the community.Atlanta: US Department of Health and Human Services: 3-4.

Gomez LF, Sarmiento OL, Parra DC, Schmid TL, Pratt M, JacobyE, Neiman A, Cervero R, Mosquera J, Rutt C, Ardila M, PinzonJD. 2010. Characteristics of the built environment associatedwith leisure-time physical activity among adults in Bogotá,Colombia: A multilevel study. Journal of Physical Activity andHealth 7 (Suppl): S196-S203.

Heath GW, Brownson RC, Kruger J, Miles R, Powell K, RamseyLT, and the Task Force on Community Preventive Services.2006. The effectiveness of urban design and land use andtransport policies and practices to increase physical activity: Asystematic review. Journal of Physical Activity and Health 3(Suppl): S55-S76.

Kahn EB, Ramsey LT, Brownson RG, et al. 2002. Theeffectiveness of interventions to increase physical activity.American Journal of Preventive Medicine 22: 73-107.

Kerr J, Sallis JF, Owen N, et al. 2013. Advancing science andpolicy through a coordinated international study of physicalactivity and built environments: IPEN adult methods. Journal ofPhysical Activity and Health 10 (4): 581-601.

King AC, Winter SJ, Sheats JL, Rosas LG, Buman MP, Salvo D,Rodriguez NM, Seguin RA, Moran M, Garber R, Broderick B,Zieff SG, Sarmiento OL, Gonzalez SA, Banchoff A, Rivera J.2016. Leveraging citizen science and information technology

for population physical activity promotion. Translational Journalof the American College of Sports Medicine 1 (4): 30-44.

Lu Y, Xiao Y, Ye Y. 2017. Urban density, diversity and design: Ismore always better for walking? A study from Hong Kong.Preventive Medicine 103: S99-S103.

Sallis JF, Cerin E, Conway TL, et al. 2016. Physical activity inrelation to urban environments in 14 cities worldwide: A cross-sectional study. The Lancet 387 (10034): 2207-2217.

Salvo D, Reis RS, Stein AD, Rivera J, Martorell R, Pratt M. 2014.Characteristics of the built environment in relation to objectivelymeasured physical activity among Mexican adults, 2011.Preventing Chronic Disease 11: E147.

Salvo D, Sarmiento OL, Reis RS, Hino AA, Bolivar MA, LemoinePD, Gonçalves PB, Pratt M. 2017. Where Latin Americans arephysically active, and why does it matter? Findings from theIPEN-adult study in Bogota, Colombia; Cuernavaca, Mexico;and Curitiba, Brazil. Preventive Medicine 103: S27-S33.

Schmid TL, Pratt M, Witmer L. 2006. A framework for physicalactivity policy research. Journal of Physical Activity and Health3 (Suppl 1): S20-S29.

United Nations Department of Economic and Social Affairs,Division for Sustainable Development Goals. 2015. SustainableDevelopment Goals.https://sustainabledevelopment.un.org/sdgs. Accessed 25January 2018.

U.S. Department of Health and Human Services, Physical ActivityGuidelines Advisory Committee. 2018. 2018 Physical ActivityGuidelines Advisory Committee Scientific Report. Washington,DC: U.S. Department of Health and Human Services.https://health.gov/paguidelines/second-edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.1.1, 1.1.2, 1.4.2, 2.1.3, 2.2.1, 2.2.2, 2.2.3, 2.4.6,2.5.2, 3.7.1, 3.8.1, 3.8.2, 3.8.3, 4.1.1, 4.1.2, 4.5.3, 5.2.1

CHAPTER 15Program and Policy EvaluationFor Physical Activity andPublic Health

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  The importance of program evaluation for physical activitypromotion

»  The types of evaluation and when and how they should beused

»  The role logic models can play in program evaluation»  A six-step approach for effective evaluation

OPENING QUESTIONS»  Why should physical activity programs be evaluated?»  Does your program work?»  Does a school district policy that mandates daily physical

education classes for elementary school children result inuniform implementation across the district?

»  When should evaluation of a physical activity promotionproject begin?

»  What constitutes success in physical activity programming?

Previous chapters highlighted effective evidence-based strategies forphysical activity promotion. These strategies have been tested inresearch or practice settings and are designed for both individualsand communities. Interventions as fundamental as reminder signs atelevators help people choose to be physically active by taking thestairs instead. Projects such as improving sidewalks andneighborhood design also help people become physically active.

We know that these types of approaches, as well as specificprograms, are effective because they have been evaluated.Evaluations allow us to make quantifiable conclusions about what aprogram has been able to change (or not) and by how much. Thischapter covers fundamental aspects of evaluation and how it iscritical for advancing our knowledge of what works in physicalactivity and public health.

When to begin the evaluation of a physical activity promotionproject is a frequently asked question. Evaluation plans should beintertwined into all aspects of program planning from the program’sinception. If you wait until the project is underway to start thinkingabout evaluation, you’ve waited too long.

Published research offers many ideas for programs to increasephysical activity. The translation from science to practice is animportant aspect of public health, not only in physical activity, but inall fields. A new program at a senior center designed to reduce therisk of falls by promoting balance exercises, a walk-to-schoolprogram that encourages and rewards children and their families forgetting to school without the means of a car, a worksite walkingprogram that uses pedometers and gives employees breaks on thecost of their health insurance if they remain physically active, or acompany-wide program providing all employees free public transitcards as well as paycheck bonuses for biking or walking to work areall examples of programs to promote physical activity.

Despite the contributions of science and its continuing evolution,the importance of measuring the effectiveness of a particularphysical activity program cannot be overstated. Using the example ofthe senior center balance program, we would want to know thefollowing: How many adults in the senior center attended the balanceexercise classes? How frequently? Were the instructors trainedaccording to protocols? Were the instructors effective in deliveringthe program? Were there any injuries? Was the program effective inreducing falls among participants? Was there a dose-response effect—that is, did people who participated more frequently in the programexperience a lower risk for falls than infrequent participants did?Each of these questions (and more) addresses a critical aspect ofprogram evaluation.

Program evaluation is important for many reasons. Obviously,you want to know whether your program has had the desired effect;therefore, quantification of the effects on participants is important.You have spent much effort putting the program together anddelivering it—did it work the way you wanted? Did participantsincrease their physical activity? By how much? Was the increaseenough to elicit changes in health status?

In addition to answering these fundamental questions, programevaluations also serve other important functions. For example, a

good program evaluation can be used to plan for resources—funding, personnel, and program materials—which can help toensure overall success. Funders usually want a well-designedprogram evaluation that will reassure them that their investmenthelped participants. Evaluations can also identify program strengthsand weaknesses—after all, some things will go right, some will gowrong, and some will be unexpected. If the program was successful,what aspects likely led to the success? What aspects needimprovement? If the program is an ongoing one—say, a walk-to-school program—an evaluation can shed light on participation trendsand suggest reasons for any shifts observed from year to year. Forexample, did the hiring of a new program coordinator havenoticeable effects on participation? What did the new programcoordinator do that resulted in the increase in participation? Did thetiming of these new activities coincide with the observed increases inparticipation? Program evaluation, in short, is a set of strategies tohelp us understand what happened as a result of our efforts.

What policies in your community or neighborhood support orinhibit physical activity? How can they be changed?

Evaluation strategies can also be used in the larger context ofpublic health policy development and implementation. For example,does a new municipal policy designed to increase bicycle usethrough the construction of bicycle lanes actually result in morebicycling among residents in that part of the city? If there areincreases in bicycle lane use and bicycling, when did the increasesoccur? Are they limited to certain times of the day or days of theweek? Are the increases transient, or can they be sustained over thecourse of months and years? Additionally, although this bookfocuses on physical activity and public health, depending on theprogram evaluated, there may be co-benefits of these programsworth measuring. In the previous bicycling example, for instance, wemay be interested in measuring if there was also evidence of lessmotor vehicle traffic in the same area. In fact, some of the aspectsoften thought of as co-benefits of physical activity-promotingstrategies or policies are actually the main reason why the programswere implemented by stakeholders in the first place. These reasonsmay include reducing congestion, improving air quality, andimproving mobility equity, among many others. Another criticalevaluation question to ask is if there were any unexpected outcomesor increases in adverse events (such as more bicycling-relatedinjuries) as a result of the new policy. As with programs to increaseindividual physical activity levels, a good evaluation design candemonstrate the impact of policies aimed at groups of people,including those in cities, states, and larger geographic regions.

A Physical Activity Evaluation Framework proposed in 2002 bythe U.S. Centers for Disease Control and Prevention (CDC) is stillrelevant and helpful in the development and follow-through ofevaluation strategies for physical activity programming (USDHHS2002). The framework has six crucial steps:

1. Engage stakeholders.2. Describe and plan the program.3. Define the evaluation.

4. Gather data.5. Develop conclusions from the evaluation.6. Communicate findings to ensure use.

Stakeholders are people and organizations with direct or indirectinterests in the project. They can include funding agencies, targetpopulations, policy leaders and decision makers, project staff, andthe evaluation team. Stakeholders should be included in the programand its evaluation early in the process. Although the interest of eachstakeholder group is unique (e.g., target populations have differentinterests than, say, decision makers), engaging all of them atmultiple levels is important. This engagement process should involvecommunications strategies and briefings to ensure that all have anadequate understanding of the project. Evaluation efforts are usuallya good meeting ground for project stakeholders because all have acommon interest at some or all points along the formative, process,outcome, or cost-effectiveness framework for evaluation. Chapter 16provides more information on developing and maintaining productivepartnerships for public health programming.

WAYS TO MEASURE PROGRAM AND POLICYEFFECTIVENESSAs soon as the program has been defined, thoughts should turn todefining the evaluation. This definition is an interactive process thatcan result in changes to the program plan. Because the programimplementation plan and the evaluation plan inform each other, theyshould be addressed simultaneously. Asking questions aboutformative, process, outcome, and cost-effectiveness evaluationshelps to clarify aspects of the program that may not have been partof the original idea. The logic model, discussed later, helps to createthis interactive experience.

Figure 15.1   Four evaluation categories for a physical activity promotionprogram.

Although the evaluation questions one can ask about a physicalactivity program may seem endless, they can be convenientlycategorized into four categories (see figure 15.1).

FORMATIVE EVALUATIONFormative evaluation is the first level of a physical activity programevaluation. In formative evaluation, the fundamental questions focuson the needs, utility, and design features of a physical activitypromotion program or policy and its individual components.Questions asked during the formative evaluation stage do not focuson the expected outcome (e.g., changes in physical activitybehaviors), but rather on the overall design of the program.Formative evaluation questions for the senior balance exerciseprogram discussed earlier could include the following: What is theextent of the problem of falling in the group? How frequently willparticipants be willing to come to the exercise classes? Willincentives be needed to increase participation? Is there a leader inthe target population who can assist with outreach? What kind ofequipment will be needed? How should instructors be trained?Clearly, this information can help the program manager or policydecision maker craft components that will have the best chance ofhitting the intended target.

The primary information sources of data during formativeevaluation are (1) expert opinion and previous work and (2) thetarget population of the program. Expert opinion, including that of thepeople implementing the program, comes from previous experience,similar work in other settings, published and unpublished examples,and other sources. The experiences of people who have donesomething similar can be invaluable to a program manager lookingto build a physical activity promotion program. Often, theseexperiences are not published and are available only throughnetworking with people who have similar intentions. A quick searchof the Internet or published literature indexing services (such asMEDLINE), or both, can begin the journey down the road togathering expert opinion.

Needs assessments provide the second source of data forformative evaluations. Needs assessments can be formal,standardized surveys or interviews, or more qualitative discussionswith key people knowledgeable about effective strategies. However itis done, the general purpose of a needs assessment is to gatherinformation from the target population (or one that is similar). For themunicipal bicycle lane example, good needs assessment questionswould be, How great is the need? Would people even be interestedin using the bicycle lane? If not, why not? If so, what will keep ridersusing the bicycle lane over time? Will incentives to participate behelpful? How about disincentives to driving in the same area? Whattype of outreach should be used? In other words, what might work tofill the need?

Formative evaluation should be used throughout the program.Although it is necessary before the program starts to determine thebest targets and strategies for implementation, it should not stoponce the program begins. A well-designed formative evaluationprovides feedback throughout program implementation so thatchanges and adjustments can be made. For example, interviewswith participants and nonparticipants in a balance exercise class forseniors can help program planners understand the characteristics of

each group, why some continue to come, and why others droppedout or never came. They can then adjust the program accordingly.

PROCESS EVALUATIONUnlike formative evaluation, process evaluation focuses onprogram or policy implementation. Of interest is how well thephysical activity program or policy is operating and what can be doneto improve those operations. Process evaluations help programmanagers assess the quality of program or policy delivery. Theyexamine delivery strategies that appear to be successful and thosethat may not have worked as planned. Both are important not onlyfor evaluating the program or policy, but also for informing futureefforts.

Process evaluation should include the assessment of deliveryalternatives. Program directors and policy decision makers canlearn how best to deliver a program or implement a policy by testingtheir strategy against an alternative. For example, in a walk-to-schoolprogram, a pilot test could be designed to determine whether leader-supported walking groups (a parent volunteer leads children toschool) result in more children walking to school than individualgroups of children and their families. Such a systematic approachmakes for a much stronger evaluation. Alternatives can be identifiedin the formative evaluation stage (discussed earlier), with input frompotential program participants or experts. They can then be testedduring a process evaluation.

Using the balance exercise class for seniors example, processevaluation questions may include the following: Are all exerciseclasses being offered as scheduled? Is instructor training andcertification being offered consistently according to predeterminedprotocols? What is the attendance at the classes? How do thesedata compare to prestated goals? Are there trends in classattendance over the weeks and months that the program is beingoffered? Are other systems that have been put in place working as

intended? Why or why not? What program adaptations seem toaffect attendance?

The information gleaned from these process evaluation questionscan be useful for monitoring the implementation fidelity of theprogram or policy. Implementation fidelity refers to the extent towhich the program or policy is being implemented as originallyplanned. For instance, do all senior balance exercise classes followthe preestablished curriculum? Or, do all balance exercise classesstart on time? Additionally, process evaluation data can be used forunderstanding the program or policy outcome evaluation data(discussed next). For example, if outcome data for the balanceexercise class show one or two sites that have reduced the risk offall-related injuries among participants by 60 to 80%, the processevaluation data can be used to determine whether differences inimplementation exist between the sites that are doing well and thosethat are not. If class attendance was routinely very high at the siteswhere falls have become less prevalent—and conversely,attendance was very low or intermittent at sites that have seen nochange in the risk of falling among participants—it could be that thedose of physical activity was higher among those participants whoare now at lower risk. Clearly, this process is not linear, but requiresan understanding of evaluation outcomes on all levels.

OUTCOME EVALUATIONOutcome evaluation, sometimes referred to as impact evaluation,focuses on cause and effect. Did the program or policy have theintended effect on the outcome of interest? For the purposes ofphysical activity promotion programs and policies, the outcome ofinterest is usually increasing levels of participation in overall physicalactivity, or in a specific physical activity (e.g., bicycling). Questionsabout the design and implementation of the program or policy havebeen answered in the formative and process evaluation stages. Nowthe question is, Has the program or policy increased physical activitybehavior? Outcome evaluation seeks to answer this question while

also assessing, by process and formative evaluations, how theintended effects were reached (or not). Outcome evaluation metricsfor physical activity promotion programs or policies could includeminutes per week that the target population engaged in moderate- orvigorous-intensity physical activity, changes in their physical fitnesslevels, the percentage of the target population meeting physicalactivity guidelines, or the number of people bicycling for practicalpurposes at least once per week.

Because cause and effect is of central interest in outcomeevaluation, changes in metrics such as these are often used asoutcome (impact) measures. This, of course, assumes that abaseline assessment was done prior to the start of the program orimplementation of the policy that will allow the calculation of changein the outcome of interest.

Outcomes of physical activity promotion programs and policiescan be assessed using any of the measures discussed in chapter 4,with each having its strengths and weaknesses. In the walk-to-school example, the number of pedometer-measured steps thatrandomly selected students take per day, both before and afterprogram implementation, may be an important outcome of interest.

EVALUATION QUESTIONSPhysical activity evaluations come in all shapes andsizes. One characteristic of successful evaluations isthat they have very clearly conceptualized evaluation

questions. This helps define the what, the how, and the whofor the target population as well as for the programstaff. Before starting any physical activity evaluation,program planners should work hard to state the questionsas clearly as possible.

The underlying reasons for observing an outcome can be asimportant as measuring the outcome itself. To this end, physical

activity program and policy evaluations also focus on hypothesizedupstream determinants as well. Upstream determinants are theknown or hypothesized factors that cause a certain outcome (or donot cause a certain outcome) to a person or community involved in aprogram. For example, self-efficacy (i.e., in the context of thisexample, a person’s belief in his ability to become more physicallyactive and sustain that behavior) is a likely mediator in participationin physical activity. If the balance exercise program for seniorsshows an increase in participants’ self-efficacy and no such increasein those who did not participate, then the program evaluator mightreasonably conclude that increases in participants’ beliefs that theycan do the exercise program are one of the reasons physical activityincreased in the group. A thorough outcome evaluation of a physicalactivity program not only measures the effects of the program orpolicy on physical activity behavior, but also suggests possibleupstream determinants of that behavior. This gives program staff abetter understanding of the mechanisms through which the programmay be working.

COST-EFFECTIVENESS EVALUATIONA final category of evaluation, and one that is often overlooked inpublic health evaluations, is related to the economics of the programor policy. The purpose of a cost-effectiveness evaluation is toassess not only the overall costs of delivery, but also how thesecosts compare with those of alternative program delivery options.Also of interest is how the costs of program or policy delivery andimplementation compare to costs (real or estimated) of not deliveringthe program or policy.

In public health, the costs related to health issues (short-term aswell as lifetime) must be balanced against program delivery costs.These health costs include the money spent to treat a disease,illness, or medical condition per person as well as indirect costs suchas loss in productivity. Although a complete treatment of methods ofcost-effectiveness evaluation is beyond the scope of this textbook,

the basic message is that this form of evaluation should not beoverlooked. In the balance exercise program for seniors example,costs of implementation include staff salaries, physical resources,evaluation costs, and participation time (the cost of doing one thingat the expense of something else). These costs are then measuredagainst any medical care expenditures (savings) that may be due tothe balance exercise program (e.g., fewer emergency room visits,bone fractures, joint replacement surgeries).

Ding and colleagues (2016) published a study examining theglobal economic burden of physical inactivity. Using information onthe known effects of physical inactivity increasing the risk of differenthealth outcomes (e.g., cardiovascular disease, diabetes, cancer), aswell as information on the cost of these conditions to health systemsaround the world each year, they estimated that physical inactivitycost health care systems $53.8 billion (international dollars) in 2013.Additionally, they estimated that deaths due to physical inactivitycontribute to $13.7 billion in productivity losses each year, withphysical inactivity being responsible for 13.4 million years lost due todisability (disability-adjusted life-years: DALYs).

Laine and colleagues (2014) conducted a systematic review of theevidence on the cost-effectiveness of different physical activitystrategies. Cost-effectiveness analyses use information on physicalactivity program costs as well as gains in health outcomes to beexpected from increases in physical activity (e.g., lower risks of heartdisease, some cancers, and diabetes). The results of the synthesisof this evidence showed that the evidence-based physical activitypromotion strategies highlighted in chapters 11 through 14 of thistext provided a good value for the money needed to implement them.In their review, Laine and colleagues found that among the mostcost-effective strategies to promote physical activity were theexpansion of community trails and paths ($0.006 per MET-hourgained [2012 USD]), the use of pedometers as a behavioral strategyto increase walking ($0.014 per MET-hour gained [2012 USD]), andschool-based physical activity promotion programs ($0.056 per MET-

hour gained [2012 USD]). Although there is a wide range of costsand benefits for evidence-based and effective physical activityprograms, for many of them, the health gains associated withincreased physical activity far outweighed the costs.

HOW MUCH SHOULD AN EVALUATION COST?Program planners frequently neglect to budget for anadequate evaluation, particularly at the proposal stage.Even the best, most innovative physical activity promotionprogram will be unable to demonstrate effectivenesswithout an adequate evaluation budget. How much money isneeded? Although there are no clearly developedguidelines, a good rule of thumb is to dedicate 10% of anoverall project budget to evaluation activities(personnel, data collection, analysis, and reporting).

Of the four types of evaluation covered in this chapter, the cost-effectiveness evaluation often has the most influence on policymakers and leaders. If a physical activity promotion program orpolicy is shown to actually save money by reducing the burden (andcosts) of disease and disability, leaders and policy makers oftenconsider it a wise investment.

LOGIC MODELS FOR PHYSICAL ACTIVITY PROMOTION ANDPOLICIESThe first steps of evaluation are interlaced with the overall programdevelopment and delivery. The who, what, where, when, why, andhow questions are answered in this phase. Who is your targetaudience? What do you want the target audience to do? When doyou want them to do it? How will it get done? Who is in charge ofwhat aspects? In these early steps, the logic model for evaluationshould be developed and refined because it will assist in evaluationas well as overall program development.

Program evaluation in physical activity and public health can getvery complicated. From the initial framing of the evaluation questionsand understanding antecedents and outcome relationships, programmanagers must keep track of many inputs, outputs, and therelationships between them. Logic models provide the hub aroundwhich all evaluation activities can be linked, and describe and definethe interrelationships of resources, the target population, short-termand long-term effects, and the ultimate desired outcomes.

A logic model is fundamentally a graphic or narrative descriptionof the processes and interrelationships that can lead to a result(cause and effect). The most fundamental use of a logic model is toensure consistent communication among project personnel andstakeholders. A well-constructed logic model helps everyoneinvolved or interested in a project work from a consistent set ofterminology and gain a common understanding of the intended andunintended (the expected and unexpected) consequences of aprogram or policy. Finally, the logic model helps to drive program andpolicy evaluations in a timely manner when coupled with a projecttimeline. A schematic of a generic logic model for program and policyevaluation is found in figure 15.2.

Figure 15.2   Schematic of a logic model for physical activity programevaluation.

The interrelationships of interest actually begin in the lower right-hand corner of the model in the area labeled “Ultimate goal.” In fact,it is sometimes easier to build a logic model from right to left ratherthan from the more natural left to right. The ultimate goal of mostphysical activity promotion programs and policies—although notoften measured in the context of specific programs or policies—isimproved health for the participants. This could be determined byexamining risk and rates of disease or mortality. Although suchoutcomes are central to the reasons for promoting physical activity,waiting for some of them to happen, or not to happen, can take yearsand is beyond the scope of measurement for many programs andpolicies, particularly those interested in more short-term behaviorchanges. Although ultimate goals are beyond the horizon for manyphysical activity promotion programs, program managers shouldnonetheless keep them in mind because they are a reminder of whythe programs and policies exist.

Of note, each of the four ways to evaluate a physical activityprogram or policy (formative, process, outcome, and cost-effectiveness) detailed in the preceding section is part of theevaluation framework and is overlaid onto the logic model schematic.

Outcomes, which are clearly of interest in a physical activitypromotion program, are presented schematically in figure 15.2immediately above (and before) the ultimate goal. Outcomes can beconceptualized in terms of time. What can be expected (and shouldbe measured) shortly after program implementation (short-termoutcomes)? What can be expected after short-term outcomes (mid-term and long-term)? Short-term outcomes of a physical activitypromotion program could include improvements in knowledge, skills,initial program participation, and physical activity behaviors. Mid-termoutcomes could include ongoing program participation and costsassociated with continuing program delivery. Long-term outcomescould include ongoing participation in physical activity after theprogram has ended, changes in physical activity participation amongthe family members of program participants, direct and indirect

costs, and possibly policy changes to maintain the program. As isshown in figure 15.2, outcome, cost, and some process evaluationactivities can occur in each of these outcome categories.

Moving to the left in figure 15.2, the logic model is also used todefine the processes of both the program and the targetpopulation(s) (audience). The audience for a program should befairly well defined, but could also include subgroups such as familymembers or neighbors not directly participating in the program.Activities of the program should be defined as processes as well.These include training sessions for the staff members who willactually deliver the program and specific activities (e.g., exerciseclasses, educational activities or products, special events such asmass participation events, stakeholder meetings, communicationsactivities). Formative and process evaluation strategies also occur inthe processes phase.

Why does changing public policy about physical activitypromotion require many steps over time?

Next in figure 15.2 (to the left) is resources. A thoroughunderstanding of resources (and how to acquire and manage them)is critical to include in a program evaluation. Without resources,programs don’t exist. Resources can certainly include funding, butthey also include paid personnel, volunteers, the time needed fromall staff, partnerships (e.g., other stakeholders in the program), andthe physical venue (e.g., places for the exercise classes). Items inthe “Resources” box in figure 15.2 are limited to those that aprogram evaluation staff can control or measure. Formative

evaluation is used to assess and define the resources needed for aprogram.

The formative evaluation should involve defining and clarifying theneed for the program before initiating it. This process could includeanalyzing health data (linking to the ultimate goal discussed earlier),gathering input and determining demand from stakeholders in thetarget population (e.g., bicyclists in the case of constructing bicyclelanes), or conducting surveys. This needs assessment is used tojustify program development (and consequently, evaluation). Needsassessments can be standardized (e.g., questionnaires) or moreinteractive (e.g., expert opinion). Physical activity programs shouldnot be developed or delivered without a clear understanding of theirnecessity and the ultimate goal.

The final consideration when developing a physical activityprogram is uncontrollable external factors. Factors beyond thecontrol of program staff and participants can negatively affect anystep along the logic model. Although program staff may not be ableto control outside influences (e.g., competing programs or changesin the weather that may influence physical activity participation), it ishelpful to recognize these possibilities and plan accordingly tominimize their effects.

Each logic model is unique because each program is unique, asare their evaluation processes and needs. The generic framework infigure 15.2 should be modified according to the needs of the specificprogram. Because logic models can get very complex, programmanagers should start with a basic structure and then continue todevelop it as program planning and a work plan emerge.

A real-life example of a logic model for a physical activitypromotion program is shown in figure 15.3. The Walk a Hound, Losea Pound project seeks to increase physical activity participation bypromoting dog walking in a community (USDHHS 2010). Can youidentify unique aspects of this logic model that would not show up inothers?

EVALUATION DESIGNSThe success of a physical activity program or policy often restslargely on its evaluation design. This generally falls into two broadcategories: experimental and observational. Experimentalevaluation studies, considered to be the gold standard, arecharacterized by one important aspect that observational studies donot have: randomization. With randomization, people, groups ofpeople, or places are randomly assigned to the program treatment orto a control (i.e., not receiving the treatment). Randomization hasmany benefits, but its most important advantage is that it distributesany unknown errors randomly among the treatment and controlgroups. This is significant because unknown errors can affect theresults of a program evaluation, thereby affecting the inferencesdrawn from that evaluation.

Unfortunately, randomization is rarely possible in the real world ofphysical activity and public health. People must live their lives, andassigning people to a no-physical-activity control group is not entirelyethical, particularly because we know the health benefits of physicalactivity. Experimental evaluation studies for physical activity andpublic health promotion programs have proven most useful when theprograms were short and focused on specific (smaller) groups ofpeople.

When experimentation is not possible or impractical because ofcosts or other barriers, observational evaluation studies are auseful alternative. Often referred to as quasi-experimental designs,these programs differ from experimental ones in that they are notrandomized. Groups are divided into treatment and control based onconvenience, receptivity, targeting, and other factors. Controlparticipants or populations (i.e., those not receiving the program) areselected based on their comparability to the treatment group onfactors such as age, sex, race or ethnicity, and baseline physicalactivity participation. What the randomization procedureaccomplishes in experimental studies—spreading the unknown errorequally among groups—is accomplished by statistical techniques in

observational studies. These techniques minimize sources ofunknown variability during data analysis.

Figure 15.3   The Walk a Hound, Lose a Pound logic model.

DOSE-RESPONSE ANALYSISAdvances in physical activity research have made the one-treatment, one-control design somewhat antiquated. Moreoften, a key question is, Does the response to a physicalactivity program or policy (i.e., participation inphysical activity) depend on the dose of the program orpolicy to which a person is exposed? Three or more

evaluation groups are needed to conduct a dose-responseanalysis. These can be conceptualized in a variety ofways, but most often they consist of high-dose, medium-dose, and no-dose groups. If the results suggest that theoutcomes correlate with the dose received, cause andeffect is easier to argue.

Frequently, a clearly delineated control group is unattainable inpublic health practice. For example, if a policy mandates dailyphysical education classes for elementary school students in anentire school district, no control group would be available. In thiscase, a delayed implementation design could be used. In such adesign, all children would receive the benefit of increasing physicalactivity through quality physical education classes, but in someschools, the policy would be delayed. This would give the evaluatorsan opportunity to estimate program effects without withholding theprogram or having an “untouched” control group.

DATA COLLECTION AND ANALYSISWithout data, there is no evaluation, and therefore no facts, onlyopinions. Each question at each phase in a physical activity programevaluation must have data sources to assess the effect of theprogram. These data sources can be quantitative (e.g.,questionnaires, attendance sheets, delivery logs, productionschedules, training manuals) or qualitative (e.g., interviews). Thedata sources used in an evaluation must help answer specificquestions. For example, if a process evaluation question for thebalance exercise class for seniors involves the fidelity of classdelivery (i.e., whether the balance exercise class was deliveredaccording to schedule each week), a data system must be in placeto capture that information. If changes in balance indicators and areduction in falls are desired mid-term and long-term outcomes ofthe project, data systems must be able to capture that information.

Data system development and data collection can be thought of as aprocess evaluation question as well.

Conclusions from the evaluation are drawn from the analysis andinterpretation of the data. Data analyses should be closely tied to thequestions asked in the evaluation and represented in the logicmodel. For example, if changes in class participation are of interest,then preprogram and postprogram data are needed. Changes inthese data can then be interpreted as due to program participation.

Changes in outcomes of interest that are due to a physical activityprogram or policy can be measured in all participants or in a smaller,randomly selected group that (hopefully) is representative of the fullgroup. If the program is small enough and the evaluation budget islarge enough, all participants can be measured before and after theprogram (and sometimes along the way) for outcome evaluation.Using our balance classes for seniors example, physical activitybehaviors and incidence of falls could conceivably be measured inall participants over the course of the program. Larger physicalactivity programs and policies that affect large groups of people orentire communities require carefully designed sampling techniquesthat identify a relevant subgroup of participants. Any changes (orlack thereof) observed in these subgroups are meant to berepresentative of the situation in the larger target population.

Conclusions from data analyses are also closely tied to theevaluation design. Control groups are especially important whenevaluating program effects. A change in those who participated inthe program cannot be assumed to be the result of a physical activityprogram without measuring similar outcomes in the control orcomparison group. For example, in evaluating the impact of newbicycle lane infrastructure in a city, if we only measured bicyclingamong people that live in that part of town, and found that bicyclingwent down at a certain point in time, we can’t necessarily concludethat the policy didn’t work. A control group (people living in a differentpart of town with no exposure to the new bike lanes), might haveshown a similar pattern of decline in overall outdoor activity at a

given point in time. This might be due to many reasons impactingboth groups, such as a city-wide crime wave making people lessprone to walk or bike, or an unusually long streak of rainy weather inthe region. The principle of using a control group and measuringchanges in the outcome, as well as process indicators, in bothgroups, applies to both quantitative and qualitative data. Having acomparable control group that is very similar to the interventiongroup (the group receiving the program/policy), provides strongerrigor to the findings of a program evaluation. When a control group isincluded, analyses of results are much less ambiguous and muchmore definitive.

CASE STUDY

WEST VIRGINIA WALKSReger-Nash and colleagues (2008) published an evaluationof a community-based physical activity promotion programcalled West Virginia Walks. This program was a follow-upto an earlier social marketing program designed toincrease walking behavior among residents in a 12-countyarea of north-central West Virginia. At the time, morethan 360,000 people resided in the target area. Theprogram goal was to increase walking behavior among 40-to 65-year-old residents who were insufficientlyphysically active at the start of the program. Theprogram was a community-wide approach, using mass mediaoutreach (see chapter 11).

The evaluation design for West Virginia Walks focusedon identifying any behavioral outcome changes inphysical activity (specifically, reported walkingbehaviors) that could be attributed to the program. Thetreatment group consisted of people living in the targetarea. The control group consisted of residents of

another county in West Virginia who were not exposed tothe program or the mass media outreach from the program.Also of interest were process evaluation markers—in thiscase, self-enrollment statistics, use of a web-basedtracking tool to help people log their behaviors, andmost important, media attention to the program. Mediaattention was an important process evaluation measurebecause the program relied heavily on mass media (i.e.,television, radio, and print) for promotion andawareness. Other process evaluation measures includeddocumentation of any municipal-level changes in policiesor in the environment designed to support physicalactivity that could be tied to the program.

Evaluation results showed several positive findings.First, there was very high recognition of the WestVirginia Walks program in the treatment area. Residentsin the area targeted by the program were significantlymore likely to recognize and know about the program thanwere residents in the control area. This processevaluation indicator suggested that the program reachedits intended audience.

Short-term changes in walking behavior were used asthe primary outcome evaluation indicator. Households inthe program area and in the control area were randomlyselected prior to the campaign. Walking and otherphysical activity behaviors of residents in theserandomly selected households were assessed by telephoneinterview prior to the start of the campaign andfollowing its completion. Differences in participationrates between the two groups were interpreted as beingdue to the campaign.

After the eight-week community-wide campaign ended,the outcome evaluation results showed that 12% of thetarget population—who were previously insufficientlyactive—became active at least 30 minutes per day on fiveor more days each week. This change translated to anaverage additional 30 minutes each week of total walkingtime in the targeted community. Similar changes were notobserved in the control community. These results showedthat the West Virginia Walks program increased physicalactivity throughout a large geographic region.

IMPORTANCE OF ASSESSING CO-BENEFITS AS PARTOF A PHYSICAL ACTIVITY PROGRAM EVALUATIONOftentimes, physical activity promotion strategies,programs, or policies have other benefits beyond theincrease in participation in physical activity among thetarget population. For example, a free YMCA programproviding sport activities for youth in disadvantagedneighborhoods may not only help improve the health of itsparticipants through increased levels of physicalactivity. The co-benefits of such a program may includebetter grades, increased social cohesion among youth inthe area, and lower propensity to engage in risky healthand social behaviors (e.g., decreased likelihood ofjoining gangs, smoking cigarettes, or drinking alcohol).Identifying and evaluating the impact of the physicalactivity program or policy on these co-benefits may provebeneficial when communicating the findings to keystakeholders who are considering scaling up theseprograms. Oftentimes the priorities of stakeholders arenot necessarily centered around physical activitypromotion, so finding the added benefits of theseprograms, and building them into the evaluation plan, isboth important and strategic.

Similarly, there may be programs or policies for whichthe main goal is not to promote physical activity. Forexample, the expansion of a bus or light-rail transitsystem in a city usually revolves around the need toimprove mobility and reduce congestion. For the creatorsand implementers of these programs or policies, physicalactivity may simply be the co-benefit. Therefore, it isimportant to work with partners outside of the physicalactivity and public health realms to make sure thatphysical activity indicators are being properly includedin the evaluation of these types of programs or policies.

An important consideration when interpreting evaluation findingsis how the results compare with those of similar programs. Thesimilarities could be in the target population, the type of program, the

type of outcomes assessed, other variables, or some combination ofthese. Consulting someone who has expertise and interest in dataanalysis and statistics (such as a local partner in a college oruniversity) can be invaluable.

DISSEMINATING RESULTSEvaluation plans and data analyses are useless unless the findingsare communicated in an effective manner to the right audience.Communication targets for evaluation results should includeimmediate stakeholders, with the first priority being those whoprovided the funding. Often overlooked, but equally important, is thecommunication of key findings to program participants. As keystakeholders in a physical activity promotion program, participants(or targets) should be informed all along the way, and receive a fullbriefing on the outcomes of the project. Although many may not havean interest in the overall results, some will. Such communicationsare critical to ensure future support, if necessary.

The format or channel of communications will differ depending onthe needs of the audiences. For example, the funding agency willneed a detailed final report with all associated materials andmethods, including the formative, process, outcome, and cost-effectiveness evaluation results. Project staff will also need suchdetail. Program participants and partners may be satisfied with top-level summary findings, and other interested parties may be satisfiedwith a fact sheet (printed or posted to a website), which summarizesthe project and key findings. Policy makers will likely be interestedonly in the key recommendations and the cost-effectiveness results.The important message here is to not underestimate the importanceof communicating the results of an evaluation, and to “speak thelanguage” best suited for the intended audience. There is no use inonly publishing the results of an innovative program evaluation in aprestigious scientific journal, which is only read by other researchers,and not communicating the key takeaways to policy makers. Policymakers are the ones that can use these results to improve the

quality and reach of their programs, and help scale effectiveprograms and policies to reach more people. On the other hand,researchers can learn better ways of doing physical activity programevaluation from each other. Identifying the key target audiences,their preferred channels of communication (e.g., scientific journals,policy briefs, infographics, YouTube videos), and disseminating theresults accordingly to all, is a critical aspect of good programevaluation.

LEADER PROFILEAnna Porter, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?During my Master’s of Public Health studies I stumbledinto bicycle commuting as an alternative to paying andfighting for parking. Bicycling quickly turned into anobsession for me, and right around the time of mygraduation some friends and I decided to start a bicyclecooperative (a nonprofit organization devoted to makingbicycling accessible and affordable to all people). Iworked in clinical research for a number of years whileriding bikes and running the bike co-op, but eventuallystarted thinking that I would like to go back to school topursue research in my own areas of interest. I had come tothe realization over the years that cities throughout theUnited States, and particularly in the southeast, were

seriously lacking infrastructure that would allow for safeand accessible bicycling, particularly for our mostvulnerable populations. Once I explored the research thatwas being done at the time on bicycling and the builtenvironment (not a whole lot as it turns out), Irecognized that this was an area where I could make animpact.

Did any one person have a major influence on your career?How?It would be hard to identify just one person, but I know Iwould not be where I am today without the support of mymentors Dr. Bill Kohl and Dr. Kelly Evenson. They haveboth been encouraging and supportive of my “niche”interests, and have pushed me to go above and beyond whatI thought was possible for myself.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?My interests primarily revolve around bicycling—whatinfluences people to bicycle and what outcomes areassociated with bicycling. I conduct research on how thebuilt environment, as well as other community- and policy-level factors, supports or hinders bicycling in diverseenvironments and populations. I also study how specifictypes of physical activity such as bicycling areassociated with morbidity and mortality outcomes. Aroundall of this is another focus of mine, which is looking atbicycling apart from the more general term of “activetransportation,” which lumps bicycling and walkingtogether. To explain further, I am looking at bicyclingdomains— recreation and transportation—as independenttypes of activities with their own motivations andinfluences.

Why do you do what you do?I think bicycles are awesome! They are a great means oftransportation, and provide innumerable benefits to boththe individual and society in terms of health and well-being, and are just fun to ride. I truly believe that ifwe can get more people off their couches and out of theircars, and onto bicycles, the world will be a better place.The biggest barriers for this, however, are safety and

accessibility. If my research can progress the narrativefor communities to consider the needs of bicyclists whendesigning streets, or for a workplace to consider how tosupport bicycle commuting, then it’s a job well done.

What are two key issues that must be addressed by 2030?One issue I think needs to be addressed is the necessityfor more research on how environments can be designed tosupport physical activity—and bicycling for transportationin particular—in rural communities. There is unfortunatelyvery little research on what types of environmentalinterventions support active lifestyles in rural areas,and populations in rural states like Mississippi are inneed of evidence-based guidance. Another issue I thinkneeds to be addressed is increased funding for alternativetransportation infrastructure that is safe, accessible,and useful, such as complete routes of protected bicyclelanes. There is a fair amount of infrastructure beingbuilt, but it is being done with small pots of money so itis often insufficient in terms of safety for bicyclistsand for getting riders where they need to go.

DO SOMETHING!Translating and scaling-up research into practice is whatoften separates public health from other scientificdisciplines. New knowledge is generated from well-designedresearch studies in all fields. Because public health isaction oriented, new research findings need to betranslated into action to improve health. New vaccines,new policies to reduce workplace injuries, and newstrategies to improve the quality of drinking water areexamples of research-to-practice translations. Can youthink of others?

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

Four kinds of evaluation strategies are important to physicalactivity programming. Formative, process, outcome, andcost-effectiveness evaluations are concerned with differenttypes of questions and should be conceptualized accordingly.Physical activity program evaluations can be experimental orobservational in design. Each has strengths andweaknesses.Logic models are useful tools to guide evaluation strategiesand help overall planning for program design andimplementation.Following six critical steps to program evaluation will facilitateits success.Data from well-designed physical activity evaluation projectsstrengthen our understanding of cause and effect.

WEB RESOURCE ACTIVITIESThe web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYDing D, Lawson KD, Kolbe-Alexander TL, Finkelstein EA,

Katzmarzyk PT, Van Mechelen W, Pratt M and Lancet PhysicalActivity Series 2 Executive Committee. 2016. The economicburden of physical inactivity: A global analysis of major non-communicable diseases. The Lancet 388 (10051): 1311-1324.

Laine J, Kuvaja-Köllner V, Pietilä E, Koivuneva M, Valtonen H,Kankaanpää E. 2014. Cost-effectiveness of population-level

physical activity interventions: A systematic review. AmericanJournal of Health Promotion 29 (2): 71-80.

Reger-Nash B, Bauman A, Cooper L, Chey T, Simon KJ, BrannM, Leyden KM. 2008. WV Walks: Replication with expandedreach. Journal of Physical Activity and Health 5: 19-27.

U.S. Department of Health and Human Services. 2002. PhysicalActivity Evaluation Handbook. Atlanta, GA: U.S. Department ofHealth and Human Services, Centers for Disease Control andPrevention.www.cdc.gov/nccdphp/dnpa/physical/handbook/pdf/handbook.pdf. Accessed 1 June 2010.

U.S. Department of Health and Human Services, Public HealthService, Centers for Disease Control and Prevention, NationalCenter for Chronic Disease Prevention and Health Promotion,Division of Nutrition and Physical Activity. Brown DR, HeathGW, Martin SL, eds. 2010. Promoting Physical Activity: AGuide for Community Action, 2nd ed. Champaign, IL: HumanKinetics.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

2.1.1, 2.1.3, 2.3.1, 2.3.2, 2.3.3, 3.1.1, 3.1.2, 3.1.3,3.2.1, 3.2.2, 3.4.1, 3.4.2, 3.7.1, 3.8.1, 3.8.2, 3.8.3,5.5.1, 5.5.5, 5.5.6

CHAPTER 16Partnership Development andAdvocacy

OBJECTIVESAfter completing this chapter, you should be able to discuss thefollowing:

»  What partnerships are and how they advance publichealth

»  The importance of developing public health partnerships topromote physical activity and exercise

»  Nine key questions for developing effective partnerships

»  How to educate, collaborate, and engage with externalpartners

»  What health advocacy is and its importance in publichealth

»  Strategies for global advocacy of physical activity andexercise

»  A detailed example of partnership development forpromoting physical activity and exercise in a largepopulation

OPENING QUESTIONS»  What do you think of when you hear the word partnership?»  Are there different kinds of partnerships?»  How could, or would, forming collaborative public health

partnerships help in the promotion of physical activity andexercise?

»  What strategies would you develop or implement to developeffective collaborative partnerships to promote physicalactivity and exercise?

Partnerships. The word conjures many images: partnerships inbusiness, dancing, life, and government (such as the UnitedNations). Partnerships involve the joining of two or more persons ororganizations for the purpose of achieving a common goal. Implied inthat definition is that both the rewards and the risks of a joint ventureare shared between the partners.

As the field of public health has evolved, it has become apparentthat population-wide health improvement, including diseaseprevention and health promotion, must focus at a level broader thanthat of the individual. The medical model of a health care system thattreats sick people is inadequate to address larger population andsocietal health problems. In public health, contrary to the medical

model, health (and disease) are considered in relation to systems,environments, social forces and norms, and regulations. Each ofthese factors, in turn, influences health behavior and diseaseoutcomes at the population and individual levels. Because of theseoverarching influences, public health relies on partnerships to workacross sectors of influence to effect systemic change. The goal is ashared responsibility (risks and rewards) for improving populationhealth.

Partnerships are necessary in the field of physical activity andpublic health. Physical activity, and barriers to physical activity,occurs throughout the day during leisure (discretionary) time,occupational physical activity, transportation-related physical activity,and school physical education. These areas are all opportunities inwhich to engage in physical activity, yet they rarely join together toachieve a common goal. The private health club industry (withgymnasiums and fitness centers) does not see a role for itself inschool-based physical education to promote physical activity inchildren. State departments of transportation, with their emphasis onincreasing capacity for motor vehicle travel (and reducing trafficcongestion) pay little attention to increasing opportunities for activetransportation with bicycle lanes and sidewalks.

Because of the broad societal implications of increased physicalactivity, partnerships are critical to the emerging field of physicalactivity and public health. Partnership development refers more toworking with organizations than individuals via collaboration. Calise,Moeti, and Epping (2010) offer a detailed explanation of how todevelop successful partnerships. The basic concepts are providedhere.

All partnerships are not created equal. Generally, they fall into oneof three categories: cooperation, coordination, or collaboration.Cooperation partnerships are usually less formal and lessstructured than the other forms. For example, two organizations canagree to partner to promote physical activity in a community, yet

each continues with its respective work. They may share resourcesand communicate on a regular basis, but not much else happens.

Coordination partnerships are more formal and structuredaround the compatibility of the mission statements of all the partners.An example would be two or more groups united to promote physicalactivity by sharing resources (e.g., personnel, finances, othertangible support) toward a common goal (e.g., a community physicalactivity promotion campaign). Coordination partnerships are more in-depth and formalized than cooperation partnerships.

Finally, collaboration partnerships are the most organized andstructured form of physical activity partnering, uniting groups orindividuals (or both) toward a common cause or mission (e.g., theglobal promotion of physical activity and exercise). Collaborationpartnerships are the most formalized type of partnership, involvesome written understanding among the partners, and require ashared long-term goal. Collaboration partnerships are characterizedby substantial resource sharing (e.g., personnel, facilities,equipment, funding), statements of shared objectives, and mutualaccountability for shared work. Clearly, the different types ofpartnerships have different expectations and levels of effectiveness.However, not all organizations have the ability or the resources tosupport collaboration partnerships. The key is that partners unitetoward a common cause—promoting physical activity.

What types of partnerships have you been involved with? Whywere they successful or unsuccessful?

KEY FACTORS IN BUILDING PARTNERSHIPSHow are partnerships built? What should you look for in potentialpartners? How will you know that the partnership is working? Thereare no easy answers to these questions, and they can be differentfor various types of partnerships. Nine key questions that canincrease the chance of successful partnerships for public health andphysical activity promotion are shown in table 16.1. Althoughanswering each of these questions will not guarantee an effective

partnership, it should increase the probability that the partnership willwork as intended.

U.S. NATIONAL PHYSICAL ACTIVITY PLANThe U.S. National Physical Activity Plan (Pate 2009, Bornstein et al.2014) is an excellent example of a partnership with the goal ofincreasing physical activity for the sake of public health. Although theresearch indicating the health consequences of physical inactivity issubstantial (and growing), no unified approach to improving thephysical activity levels of Americans was attempted prior to 2008.National action plans had existed for tobacco control, heart diseasecontrol, and other health issues, but not for physical activity.Moreover, six other countries had already established plans thatfocused specifically on physical activity (Australia, Northern Ireland,Norway, Scotland, Sweden, and the United Kingdom). The extent ofinactivity in the United States combined with the overall healthbenefits that can be realized if a higher proportion of Americans weremore physically active made it clear that a comprehensive set ofstrategies, including policies, practices, and initiatives, to increasephysical activity participation in the United States was needed. Apartnership was born.

With leadership from the U.S. Centers for Disease Control andPrevention (CDC), a coordinating committee (leadership) wasestablished. Because physical activity (and inactivity) is pervasive inthe United States, a multisector partnership was established. Thepartnership brought together representatives from transportation andcommunity planning, educational, public health, mass media, healthcare, public health and recreation, and fitness and sportorganizations. Later efforts included partnerships with business andindustry and faith-based settings.

The long-term goal of the partnership was to create a socialmovement that would dramatically increase the level of physicalactivity participation throughout the country. Broad-based input wassolicited from stakeholders and others who might contribute to the

overall goal. Finally, evaluation strategies were built into thepartnership’s work from the start. This would allow for monitoring theeffectiveness of the partnership, its partners, and the progresstoward its goal.

Table 16.1   Key Questions for Effective Public HealthPartnerships

Key question Importance

Do I need apartnership toaccomplish myphysicalactivity andpublic healthobjectives?

If the answer is no, then a partnership may not beeffective and, in the worst case, could get in the way.

Who should Irecruit?

Effective partnerships are most frequently helpful wheneach partner brings unique skills and resources. Partnerswith overlapping resources can be less helpful. Partnerswith no resources are not partners.

Once thepartnership iscreated, whoshould lead?

Strong, collaborative leadership, and a leadership plan,are critical to successful public health partnerships. Aclear understanding of the overall goal of the partnershipas well as the goals of the individual partners iscritical.

What are thegoals of thepartnership?

Clearly defined, agreed-upon, and communicated goals arecritical to minimize miscommunication and differingexpectations among partners.

What is thelevel ofinvolvement andcooperation ofeach partner?

As detailed in the text, partnerships can be at the levelof cooperation, coordination, or collaboration dependingon the interest and resources that partners bring.

How will thepartnershipoperate?

Successful partnerships most often are those with a clearorganizational structure. All partners should be clear ontheir roles and expectations for bringing or helping tolocate resources to achieve the desired goal.

On what shouldthe partnershipfocus?

Although day-to-day decisions and short-term objectivesrequire energy, it is important to keep an eye on thelong-term, overarching goal—that is, the reason thepartnership was established.

How do we get toour long-termgoal?

Successful partnerships, although always needing to focuson the long-term goal, must set a plan of achievableshort-term objectives. When attained, the sum of theshort-term objectives should help attain the long-termgoal.

Is thepartnershipworking?

Evaluation is critical to an effective partnership. Isprogress toward the common goal being made? What parts ofthe partnership are effective? What needs improvement? Areother partners needed? Evaluation in public healthpartnerships should be ongoing and integrated into thefabric of the partnerships.

Adapted from Calise, Moeti, and Epping (2010).

The U.S. National Physical Activity Plan was launched in May2010 and revisions to the plan were added in April 2016. Thepartnership was the only way such an effort could be undertaken andbrought to a positive conclusion. The partnership has now moved tospecific strategies to implement the plan. More details and updatescan be found on the National Physical Activity Plan website(www.physicalactivityplan.org).

LEADERSHIP STRATEGIES TO LEVERAGEPARTNERSHIPSThe Imperative for Leadership and CollaborationThe critical first step to effectively improve the healthof a community through increased physical activity is toestablish a coordinated leadership effort that can ensurecollaborative investment of resources within thatcommunity. The approach selected by any given communityshould be shaped by the local community’s size, resources,needs, and interests.

Community Goals and the Tools to Achieve and Measure ThemHaving established a leadership strategy that provideseffective coordination of resources and efforts, acommunity will be poised to assess local priorities, setgoals and targets, and to define the measures they willuse to track progress.

Strategies and Resources to Reach Community Goals andTargets

Evidence-Based Strategies. Both for the purposes ofeffectively improving health and for supporting good

proposals for funding, implementing evidence-based

interventions is the most effective way to use

limited resources. Many proven and promising

interventions are available to achieve better health

and to get the greatest return for the investment of

resources and effort.

Reaching Priority Populations. A key reason for usingpopulation-based approaches is to increase community

leaders’ ability to reach beyond cultural differences

and socioeconomic barriers that adversely affect some

areas of their community more than others. The

planning process that includes assessment, goal and

objective setting, strategy selection, and evaluation

must include a continuous focus on needs of priority

populations.

Getting the Resources and Sustaining the Initiative.

With clear targets and a plan to achieve them, a

community leadership team and the respective sector

representatives working to implement programs will be

more fully prepared to articulate how requests for

funding will be used.

Return on Investment. Community leaders promotingphysical activity initiatives are in a uniquely

strong position when it comes to advocating for their

initiatives. That is because the science connecting

increased physical activity to health improvements is

solid; and there is strong evidence that investments

in improving health through physical activity result

in cost savings for individuals and employers and

more.

Implementing and Evaluating Plans to Increase PhysicalActivityAfter the leadership team has assessed needs andpriorities; set goals, objectives, and measures; chosenevidence-based strategies; and procured resourcesnecessary to begin working toward the objectives, it istime to begin implementing the plans established.

STRATEGIES FOR PHYSICAL ACTIVITY ADVOCACY

Public advocacy involves recommending, advancing, and supportinga particular cause or policy. Physical activity advocacy, therefore,involves publicly advancing and supporting improved health throughincreasing physical activity. Clearly, such an enormous task couldtake a variety of directions, from advocating for more school physicaleducation, to improving access to places to be active, to improvingcity planning to create environmental supports for physical activity.

Shilton (2008) made the case that physical activity public healthintervention has convincing scientific evidence and a broad supportbase to justify its global advocacy. As he reported, the World HealthOrganization (1995) defined advocacy for health as “a combinationof individual and social actions designed to gain politicalcommitment, policy support, social acceptance and systems supportfor a particular health goal or program” (Shilton 2006, 119). Inkeeping with the public health theme (as opposed to the medicalmodel, which focuses on the individual), Shilton also noted that “thekey goal of physical activity advocacy is not individual behavioralchange, but achieving advances in political commitment, policysupport, infrastructure, funding, and systems changes” (Shilton2006, 766).

LEADERSHIP AND PERSISTENCEThe importance of strong leadership in developing publichealth partnerships cannot be underestimated. Leadershipdoes not have to consist of just one person; it can comefrom a team or executive committee (as with the U.S.National Physical Activity Plan just discussed). Bydefinition, partnerships are inclusive—the voices of allinterested partners are heard. The contributions andinterest of partners can wane without strong leadership tohelp all partners focus on the long-term goal—whether thatgoal is to increase physical activity participation at thestate or national level, at the local community level, orat a worksite. The leadership team needs to be tenaciousand persistent to reach the long-term goal and to continue

beyond the goal with cycles of reevaluation, reassessment,reprioritizing, choosing new strategies to reach newpriorities, and then starting the cycle over again.

One need not reinvent the wheel to be a successful advocate forphysical activity; lessons learned from successful public healthinitiatives can enhance advocacy efforts for physical activity. Forexample, Shilton (2008) summarized the results of antismokinginterventions that have positively affected public health policiesglobally (as first reported by Yach et al. 2005). The dramaticdecrease in tobacco smoking in the United States is an outcome ofyears of multifaceted work; advocacy assisted in this processtremendously.Lessons Learned From Successful Antismoking Campaigns

1. A small group of dedicated, persistent, media-savvy, andpolitically astute leaders and agitators can have a significanteffect on public policy.

2. Broad-based support and well-networked coalitions are needed.3. Commitment to a comprehensive package is crucial—in this

case, a 10-point plan.4. Interventions known to be effective must be fully implemented.5. The issue of individual versus environmental action must be

addressed early, often, and well.6. Acknowledging the evidence of harm is necessary but not

sufficient for policy change.7. Decades of effort may be required.

A persuasive case can be made that as long as a disconnectexists between the scientific evidence regarding how physical activityimproves health and the lack of programs and policies that supportphysical activity for the health of populations, advocacy strategies forphysical activity promotion should be a priority. As covered inprevious chapters of this textbook, the evidence that physical activity

improves health is substantial and growing. We also know the typesof strategies that work to promote physical activity. Partnershipsmust now advocate for a long-term commitment to such strategies toimprove public health.

How does one go about becoming an advocate? Advocacy inpublic health is more art than science, but several key steps havebeen identified. Figure 16.1 illustrates five critical steps to successfulphysical activity advocacy.

FUNDINGFunding public health partnerships is always a challenge.Where does the financial support come from? How do weapply for support? How should a person or organizationbudget for a project? The answers to these and otherquestions differ with each project and partnership. Acomplete treatment of grant writing is beyond the scope ofthis text. However, a good place to begin looking forinitial financial support is members of the partnershiporganizations. When collaborative partners bring start-upmoney with them, early work is easier to accomplish.

State and local health departments, although neverflush with money, can be useful places to start seekingfunding. Community partners such as corporate supporters,parks and recreation departments, and departments oftransportation and education all can be investigated.Private foundations and local community foundations oftenhave a keen interest in health and health promotion.Partnerships are particularly attractive to fundersbecause of their naturally inclusive nature. Anotherresource would be a local college or university; facultymembers frequently have additional ideas about securingsources of funding. In short, there is no one way orsource for funding partnerships in physical activity andpublic health. You are limited only by your energy andyour creativity.

Figure 16.1   Five steps to successful physical activity advocacy.Adapted from Shilton (2008).

The first step to effective public health advocacy is to establish theurgency of the problem in a way that decision makers and otheradvocates can understand it. That urgency is most crediblyestablished with a solid grounding in the research of a particularproblem (i.e., the science base). The stronger the science, the easierthe case for urgency can be made. In the case of physical activityand public health, the science base that has established physicalinactivity as a leading cause of death, various noncommunicablediseases, and disability in the world is a very important starting pointin expressing the urgency.

Unfortunately, amassing a science base does not, by itself, makethe case for change. It is necessary, but not sufficient. Even thestrongest public health science is not usable unless it is understoodby decision makers and policy makers as well as other advocates.Although a municipal legislator is unlikely to read the most currentpeer-reviewed paper on determinants of physical activity from ascientific journal, she is likely to read fact sheets, websites, andsummaries that succinctly and credibly convey the urgency of theproblem.

WHO IS AN ADVOCATE?

The answer to this question is—anybody. Anybody can be anadvocate for change for increasing physical activityopportunities, places, and access. Decision makers toinfluence aren’t just elected officials. They can beschool principals, workplace supervisors, or neighborhoodassociations. Decision makers can even be family members.Change doesn’t happen by accident—advocates make changesfaster than they might happen naturally. One program—theActive Life Movement in Austin, Texas, USA—teachesadolescents and teenagers how to be effective advocatesfor healthy change (www.activelifemovement.org).

Once the urgency of the problem has been established in anunderstandable fashion, it must be creatively communicated topeople who can make a difference. This may be as simple asmaking a presentation to a corporate human resources directorregarding how much money in health care costs might be saved ifthe corporation began a physical activity promotion program.Alternatively, it could be a multipronged, systematic approach toinform governmental agencies about the problem. For example,people involved with health and health promotion could beapproached with a summary of the improvements in health thatmight be realized if the prevalence of people meeting physicalactivity guidelines increased by a certain percentage. Peopleinvolved with transportation and city planning might be approachedwith estimates of how much traffic congestion may be reduced in acertain neighborhood if bicycle lanes and sidewalks were added toencourage physical activity.

What happens to teamwork and performance when you lose a roweror two?

Communicating the urgency of the problem to people who havethe ability to do something about it is not sufficient to effect change.Advocates must be ready to offer credible solutions that preferablyhave been shown to work elsewhere. Once decision makers havebeen convinced of the need to do something, they need guidance onwhat that something is. Evidence-based strategies that have beenshown to increase physical activity are reviewed in chapters 11through 14 of this textbook.

LEADER PROFILEAlejandra Jáuregui de la Mota, PhD

Why and how did you get into the field of PhysicalActivity and Public Health?I have been passionate about physical activity sincechildhood. I started playing volleyball when I was 7 yearsold and continued to play through my undergraduate studieswhen I was part of the volleyball selective team at myuniversity. During my adolescence and young adulthood Iwas also an indoor cycling instructor and a swimmingteacher, and I went mountain biking during my leisuretime. I was so passionate about exercising and enjoyedoutdoor activities so much that I was convinced everysingle person on earth should be able to experience themany benefits of physical activity. That was when Irealized I wanted to dedicate myself to helping othersengage in and enjoy physical activity.

However, I lived in Colima, Mexico, a small town on thePacific coast with only a few graduate opportunities. Iwas very good at math and chemistry, and finished myundergraduate studies in chemistry, biology and pharmacy,despite knowing I would never dedicate myself to analyzingblood or urine samples, or work at a pharmacy. I soonstarted looking for a graduate program related to physicalactivity; at that time I had no understanding of publichealth. I applied to a master’s degree program inphysiology at Universidad de Extremadura, in Spain, and aprogram in Community Health at the University of McGill,in Canada. I also applied to a master’s degree program atthe National Institute of Public Health of Mexico (NIPH)—mainly because I was interested in the work of Dr.Salvador Villalpando, who had led some studies exploring

physical activity patterns in preschool children. I gotaccepted into all three programs, but the NIPH was theonly one to offer me a scholarship. That is how I got intothe field of public health.

For my Master of Science in Public Health degreeprogram, I explored how physical activity patterns ofpreschool children changed when entering elementaryschool, and how these changes affected body composition.That is how I managed to combine my interests in physicalactivity and public health.

Did any one person have a major influence on your career?How?There are three people who were major influences on mycareer, and who I now consider my mentors: Dr. DeborahSalvo, Dr. Michael Pratt, and Dr. Bill Kohl. They havetaught me how to be open, patient, and unselfish withknowledge. They have also been responsible for myprofessional growth and have guided me on how to create,lead, and maintain the new department of physical activityat my institution.

Finally, another major influence on my career has beenmy husband. He has always supported my professionalinterests, has encouraged me to be the best I can be, andhas reminded me of my passion for the simple things, suchas playing volleyball.

What are your current interests in the field of PhysicalActivity and Public Health and how do you translate theminto practice?I have two main interests in the field of PhysicalActivity and Public Health. The first is global, thesecond is personal. My global interest is to develop thisarea of research in my home institution, the NationalInstitute of Public Health of Mexico, and in Latin Americaat large. One of my professional goals is to positionphysical activity in the policy agenda of my country, asit has been neglected in the past years. Despite theurgent situation of noncommunicable diseases in Mexico,especially diabetes and obesity, and the implementation ofbold strategies at the national level aiming to improvethe diet of Mexicans (i.e., soda tax and regulation offoods in elementary and middle schools), most strategiesare focused on promoting healthy habits among individuals,

leaving the responsibility of living a healthy lifestyleup to each person. In this vein, I have pushed for theinclusion of environmental research at my institution byhelping develop and chair the new Department for PhysicalActivity and Healthy Lifestyles, which focuses onunderstanding not only the physical inactivity pandemic orunhealthy eating, but also the role that space and placehave in determining health.

More personally, my main research interests are relatedto the role of policy: social and built environments forpromoting healthy lifestyles, physical activity andhealthy dietary intake, and preventing noncommunicablediseases, especially obesity and diabetes. I havecollaborated with several groups with the objective ofdocumenting the national situation related to physicalactivity promotion, understanding the environment forphysical activity and healthy nutrition, and developingpolicy recommendations to improve our national policies.

I am based at the NIPH, so we have very strong ties withthe Ministry of Health and other international agencies,and since 2016 we have fostered new relationships with theMinistry of Education and the Ministry of the Environment.For example, along with United Nations Educational,Scientific and Cultural Organization (UNESCO), PanAmerican Health Organization/World Health Organization(PAHO/WHO), federal ministries, and more than 30 expertsin the field, we developed a series of recommendations toimplement a national strategy for quality physicaleducation in the Mexican school system. More recently, wehave been working closely with the new presidentialadministration to implement these recommendations, alongwith a whole-of-school approach for physical activitypromotion in all elementary and middle schools in thecountry.

Why do you do what you do?Because I love it.

What are two key issues that must be addressed by 2030?There are two major issues which I believe are the mostpressing: chronic diseases and poor quality of life.Fortunately, I believe that addressing these public healthproblems may require similar approaches—building healthierand more sustainable cities in which the healthy choice is

the easy and preferred one. This will need to be addressednot only through the public health arena, but will alsorequire aligning the interests of many sectors at manylevels. I believe this is the only solution.

Evidence of successes in other physical activity initiatives canalso be helpful to advocates. What are other people doing or sayingabout physical inactivity? Are there other examples of advocacyleadership that can assist? One very appropriate example is theToronto Charter for Physical Activity (Bull et al. 2010). The TorontoCharter, published in 2010, is a call for more political and socialcommitment on the national level to support health-enhancingphysical activity. It advocates the following four actions: (1)implementing a national plan for physical activity promotion; (2)introducing policies that support physical activity; (3) reorientingservices and funding to make physical activity a priority in education,transportation and planning, the built environment, worksites, sports,parks and recreation, and health care; and (4) developing effectivepartnerships for action. The Toronto Charter asserts that physicalinactivity is a global problem and must be addressed throughoutsociety.

THE WHO GLOBAL ACTION PLAN FOR PHYSICALACTIVITYThe World Health Organization (WHO) has taken a globalleadership position with a 12-year action plan to promotephysical activity throughout the world. The vision for theglobal action plan is “more active people for a healthierworld” and the overarching mission is to “ensure that allpeople have access to safe and enabling environments andto diverse opportunities to be physically active in theirdaily lives, as a means of improving individual andcommunity health and contributing to the social, culturaland economic development of all nations.” The planprioritizes four strategic objectives and 20 specific

policy actions within the objectives, which, ifimplemented, could increase global physical activity

levels. Clearly such an ambitious plan demands multiplepartnerships because the agenda is beyond the scope of anysingle agency. By working together to achieve the visionof this global action plan and improve health for all,partners can also accelerate progress to achieve their ownrespective goals. For more information on the WHO GlobalAction Plan for Physical Activity, explore the websitewww.who.int/ncds/governance/physical_activity_plan/en/.

Because change does not usually happen by chance, the fourthstep in physical activity advocacy is to develop and enact anadvocacy strategy. Such a strategy can involve both the political andmedia arenas. Communicating with organizations in these arenasshould be frequent to raise the profile of the issue and create ademand for change. Although less frequently addressed,professional networks and community organizations with similaradvocacy interests can amplify the message. Enlisting moreadvocates can be very beneficial to a cause.

Finally, translating and communicating the urgency to decisionmakers (step 2) may not be sufficient. Shilton (2008) calls forcreative persuasive communication tactics that keep an issueprominent in the media. Creative use of the popular media such astelevision, the Internet, and print can go a long way in getting theattention of decision makers and policy makers. Creating a demandfor change can often drive that change faster than the mostpassionate advocate.

CHAPTER WRAP-UPWHAT YOU NEED TO KNOW

Partnerships (relationships that focus on mutual cooperationand responsibility) are needed to promote physical activity

and exercise.Partnerships can be categorized as cooperation,coordination, or collaboration.There are several steps to building partnerships in physicalactivity and public health.The goal of physical activity advocacy focuses less onindividual behavioral change, and more on achievingadvances in political commitment, policy support,infrastructure, funding, and systems changes.Community physical activity plans should include leadershipand collaboration; goals and the tools to measure them;strategies and resources to reach goals and targets; andimplementation and evaluation plans.Physical activity advocates should communicate the urgencyof the problem, offer solutions, provide evidence of thesuccesses of other initiatives, use an effective advocacystrategy, and communicate that strategy well.The WHO Global Action Plan for Physical Activity is anexample of using partnerships to develop a road map forincreasing physical activity globally.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities tohelp you learn and understand the information presented in thetext. You’ll find e-Media links, flash card activities, and testquestions when you visit the page for this chapter.

BIBLIOGRAPHYBull FC, Gauvin L, Bauman A, Shilton T, Kohl HW, III, Salmon A.

The Toronto Charter for Physical Activity: A Global Call to

Action. J Phys Act Health 2010; 7(4):421-422.Bornstein D, Pate RR, Buchner D. 2014. Development of a

national physical activity plan for the United States. Journal ofPhysical Activity and Health 11: 463-469.

Calise TV, Moeti R, Epping JE. 2010. Developing partnerships. InBrown DR, Heath GW, Martin SL, eds. Promoting PhysicalActivity: A Guide for Community Action, 2nd ed. U.S.Department of Health and Human Services, Public HealthService, Centers for Disease Control and Prevention, NationalCenter for Chronic Disease Prevention and Health Promotion,Division of Nutrition and Physical Activity. Champaign, IL:Human Kinetics.

Pate RR. 2009. A National Physical Activity Plan for the UnitedStates. Journal of Physical Activity and Health 6 (Suppl 2):S157-S158.

Shilton, T. 2006. Advocacy for physical activity: From evidence toinfluence. International Union for Health Promotion andEducation 13 (2): 118-126.

Shilton, T. 2008. Creating and making the case: Global advocacyfor physical activity. Journal of Physical Activity and Health 5:765-776.

World Health Organization. 1995. Report of the inter-agencymeeting on advocacy strategies for health and development:Development communication in action. Geneva, Switzerland:World Health Organization.

Yach D, McKee M, Lopez AD, Novotny T. 2005. Improving dietand physical activity: 12 lessons from controlling tobaccosmoking. British Medical Journal 330: 898-900.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALISTThis chapter covers these competency areas as set forth bythe National Physical Activity Society:

1.1.1, 1.1.2, 1.1.5, 1.1.6, 1.2.1, 1.2.2, 1.4.3, 2.2.1,2.2.2, 3.4.1, 3.4.2, 3.4.3, 3.6.2, 3.6.3, 3.6.4, 4.2.5,4.3.3, 4.5.1, 4.5.4, 4.6.4

GLOSSARY

absolute intensity—The rate of energy expenditure required toperform any given physical activity. Often measured in METS,kilocalories (kcals), or miles per hour (mph) for activities like walkingor running; expressed in pounds (lb) or kilograms (kg) for the amountlifted in resistance training.absolute strength—The maximum amount of force one can exert,or maximum amount of weight that one can lift one time and no more(or one repetition max, 1RM).accelerometers—Small piezoelectric devices that estimate physicalactivity energy expenditure by measuring movement. Specifically,they measure the magnitude and direction of acceleration. Theyconstitute an indirect measure of physical activity.accelerometer sampling rate—The number of data points that anaccelerometer records per second.access—In broad terms, access is the ability to approach or usesomething. In a physical activity and public health context, it includesgeographic access (availability and accessibility) and economicaccess (ability to pay to use a resource, such as a gym).accumulation—Acquiring a specific dose of physical activity orexercise to achieve a specific goal (such as health, physical fitness,or peak performance) by performing several shorter bouts, thenadding together the time spent during each of these bouts (e.g.,three bouts lasting 10 minutes each to achieve 30 minutes of dailyphysical activity or exercise).

action stage—The fourth stage of the transtheoretical model, inwhich a previously sedentary person has recently become physicallyactive and is perhaps now meeting the physical activity guidelines of150 minutes per week of moderate-intensity physical activity.active transport—Walking, cycling, or other human-poweredmethods (e.g., skateboarding) of transportation.activities of daily living (ADLs)—Minimal self-care activities that aperson must accomplish each day. Examples include bathing,dressing, feeding, and using the toilet.adverse cardiac event—A composite term to describe severalacute cardiac abnormalities. In relation to physical activity andexercise, the two most frequently studied events are cardiac arrestand sudden cardiac death.advocacy—Public support for advancing a defined cause, causes,or policy.aerobic activities—Forms of activity that are intense enough andperformed long enough to maintain or improve an individual’scardiorespiratory fitness. Aerobic activities commonly require the useof large muscle groups.aerobic capacity—Activities that stress the ability to maintain highpercentages of O2max for extended periods of time (e.g., 20minutes or longer).aerobic power—Activities that require high levels of oxygen deliveryto the working muscles and last from 3 to 15 minutes.affect—The feeling that results from being physically active. Forexample, the amazing feeling of scoring a goal compared to thegeneral intent to stay physically fit is what motivates some people tobe physically active.age-related decline in cognitive function (also known as age-related cognitive decline or normal cognitive aging)—Thegradual loss of cognitive abilities over time (vocabulary, conceptualreasoning, memory, processing speed) due to aging.

air displacement plethysmography—A technique based on thesame displacement principles as hydrostatic weighing that usesmultiple sensors in the measurement unit to measure airdisplacement in a known period of time.all-cause mortality—Death due to any cause.Alzheimer’s disease—The most prevalent type of dementia, withsymptoms including memory loss and behavioral and cognitiveproblems that deteriorate over time.anaerobic activities—High-intensity activities that exceed thecapacity of the cardiovascular system to provide oxygen to musclecells for the usual oxygen-consuming metabolic pathways.Anaerobic activity can be maintained for only a short period of time,about 2 to 3 minutes. Sprinting and powerlifting are examples ofanaerobic physical activity.anaerobic capacity (or mean peak power)—Short-burst, high-intensity movements that last between 15 seconds or up to threeminutes, and stress additional anaerobic energy pathways of thebody.anaerobic power (or peak power)—Short-burst, high-intensitymovements that last less than 15 seconds and stress the anaerobicenergy pathways of the body.anorexia nervosa—A psychological eating disorder characterizedby abnormally low body weight and excessive fear of weight gain.atherogenic dyslipidemia—Low high-density lipoprotein (HDL)levels and high triglyceride levels with small, dense low-densitylipoprotein (LDL).audit—A method of measuring the built environment based on directobservation through inventories, and allowing for quantifying aspectsat the community and street levels.basal metabolic energy expenditure (BMEE)—The energyexpended to maintain breathing and circulation while at rest; usuallyexpressed as kilocalories.

bioelectrical impedance analysis (BIA)—A technique that sends alow-amperage electrical current through surface electrodes on thebody (e.g., the wrist and ankle), and the measurements of theresistance to the current permit the estimation of body compositionusing prediction equations.biomechanics—The study of physics applied to the understandingof movements in living organisms.biostatistics and data science—The application of mathematicaland statistical techniques to the analysis of public health problems.body composition—The relative proportion and distribution of fat,lean mass (muscle and bone), and minerals in the body.body mass index (BMI)—A frequently used screening measure thattakes into account a person’s height as well as weight. To calculateBMI, divide weight in kilograms by height in meters squared:

BMI = weight (kilograms) / height (meters2)body weight status—A concept encompassing issues related toweight gain, loss, and maintenance.bone mineral density—A measurement of the amount of calciumand other minerals in a segment of bone, usually measured at thehip or lower spine.bone strengthening activities—Physical activities that maintain orimprove muscular strength (how much resistance can be overcome),endurance (how many times or for how long can resistance beovercome), or power (how fast can the resistance be overcome).built environment—Any aspect of the environment, urban or rural,that has been created by people. This can include structures likesidewalks, roads, stoplights, crosswalks, buildings, and parks.bulimia—A psychological eating disorder characterized by bouts ofextreme overeating (bingeing) followed by bouts of depression andself-induced purging.cancer—A group of diseases with processes associated withuncontrolled abnormal cell growth and proliferation.

cardiovascular disease (CVD)—The cardiovascular diseases(CVDs) are a group of disorders of the heart and blood vessels thatinclude coronary heart disease (CHD or ischemic heart disease,heart attacks), cerebrovascular disease (stroke), elevated bloodpressure (hypertension), peripheral artery disease, rheumatic heartdisease, congenital heart disease, and heart failure.chronic diseases (or noncommunicable diseases)—Illnesses thatare not caused by a specific infectious agent.classroom activity breaks—All activity performed in the classroomduring classroom time regardless of intensity.clinically significant weight loss—A loss of at least 5% of bodyweight.co-benefits—Positive aspects resulting from a physical activitystrategy beyond increases in physical activity. These may includereduced air pollution, more social interaction, lower crime, and betterequity. In some circumstances, physical activity promotion may bethe co-benefit of a program or policy with a different primary goalthan increasing population levels of physical activity.cognitive function—Cerebral processes involved in thinking andknowledge acquisition, including attention, reasoning, memory, andlanguage.collaboration—Working with one or more other person(s) toproduce a common product. The most organized and structured typeof partnership, in which the partnership is formalized in writing andthe two organizations share a long-term goal.Community Guide (officially known as the Guide to CommunityPreventive Services)—A collection of evidence-based findings andrecommendations from the Community Services Task Forcedesigned to be a resource to improve health and prevent disease.community-wide campaign—A recommended informationalapproach to increase physical activity using highly visible, broad-based multicomponent strategies.

compliance—People’s ability to continue to participate in regularphysical activity or exercise programming.Comprehensive School Physical Activity Programs—A school-based, multicomponent approach that is designed to increasephysical activity.computed tomography (CT)—A research and medical diagnostictool that relies on X-ray technology to quantify the amount of fattissue and other tissue in the body or in a region of the body.connectivity—A concept referring to the ease of getting from oneplace to another within a neighborhood while using the road networkof a city to walk or bike. In a part of the city where the streets follow agrid pattern, it is easy to use the street network (assuming sidewalksor bicycle lanes are available) to move around by walking orbicycling. In parts of the city where intersections are very far fromeach other, or there are a lot of dead-end streets or culs-de-sac,connectivity is considered to be suboptimal.contemplation stage—The second stage of the transtheoreticalmodel, in which a person may be thinking about making a change tobe physically active a short time in the future, and may be aware ofthe benefits, but has not yet reached a tipping point to make thebehavior change.cooperation—Working together or complying with requests.Cooperation usually involves a less formal partnership, in which twoorganizations share resources and communicate on a regular basis.coordination—Organization of multiple inputs or elements to makeit easier to produce a common product. Coordination tends to be amore formal partnership in which two organizations unite to promotea cause by sharing resources towards a common goal.cost-effectiveness evaluation—A component of programevaluation focused on estimating the overall costs of programdelivery, how these costs compare with those of alternative programdelivery options, and how the costs of program or policy delivery and

implementation compare to the cost of not delivering the program orpolicy.counts (accelerometry)—A numerical value, in an arbitrary scale,assigned to the acceleration recorded by an accelerometer in agiven time point.cut points (accelerometry)—Physical activity intensity thresholdsderived by formulas converting counts per epoch (usually counts perminute) to energy expenditure values. Cut points indicate theminimum number of counts per minute (for this example) to be metto categorize a minute as being of sedentary, light, moderate, orvigorous intensity. Cut points are brand- and age-specific.decisional balance—A person’s ability to weigh the pros and consof being physically active and to take action based on thatassessment.delivery alternatives—A critical component of a well-conductedprocess evaluation. Program delivery policy implementation can beimproved by testing it against an alternative designed for the samepurpose.dementia—A group of symptoms related to loss of memory andcognitive skills that are serious enough to lower a person’s ability toperform everyday tasks. Alzheimer’s disease is the most commontype of dementia.detraining—The loss of health or fitness following the cessation of aregular program of physical activity or exercise.diabetes mellitus (or diabetes)—A syndrome associated with lowinsulin secretion, a limited ability of insulin to act on target tissues tomaintain glucose homeostasis, or both of these conditions.direct observation—The only direct measure of physical activitybehavior; uses trained observers to collect standardized data onphysical activity intensity and type occurring at specific settings bygroups of people (e.g., students in a PE class, users of a park).domains—The reason for or purpose of a given physical activitybehavior, which includes discretionary time domain (also referred to

as free-time or recreational domain), transportation-based domain,occupational domain, and household domain.dose-response—The amount of physical activity or exerciseneeded for achieving health, physical fitness, or performance goals.dose-response analysis—An analysis examining if the response toa physical activity program or policy depends on the dose of theprogram or policy to which a person was exposed. Three or moreevaluation groups are needed to conduct a dose-response analysis.dose-response relationship—The relationship between the amountof an exposure (e.g., physical activity) and the overall response of anorganism (e.g., a health outcome, like cancer). In physical activityresearch, the amount of physical activity needed for achievinghealth, physical fitness or performance goals is expressed as adose-response relationship.dual-energy X-ray absorptiometry (DXA)—A technique in which X-ray beams are emitted and data are differentiated into fat mass, fat-free mass, and skeletal (bone) mass in a two-dimensional display.The DXA technique can provide precise data about a person’spercentage of body fat, as well as bone mineral density data.dynamic physical activity or exercise—Physical activity thatusually requires muscle-shortening (concentric) and muscle-lengthening (eccentric) movements.dysthymia (also known as Persistent Depressive Disorder)—Acondition of chronic mild depression.economy—The energy cost of physical activity or exercise at agiven speed or workload.Educating the Student Body Report—A major report from theInstitutes of Medicine in 2013 that detailed six majorrecommendations for action needed to improve opportunities forphysical activity in school children, using school as the hub for theseactivities.effectiveness studies—Studies in which the main outcome ofinterest relates to how well a treatment works in practice—or more

appropriately—in real life instead of in controlled settings.efficacy trials—Studies that are used to establish that a certainintervention or public health program can change a certain condition.environmental health—The branch of public health that focuses onthe built and natural environments and their effect on health.epidemic—The occurrence of cases of an illness, specific health-related behavior, or other health-related events clearly in excess ofnormal expectancy in a community or region.epidemiology—The study of the distributions and causes ofdiseases in defined populations. Epidemiology is the basic scienceof public health.epochs (accelerometry)—A time segment at which accelerometerdata is aggregated (e.g., 1-second, 10-second, 30-second, 60-second). For example, when data are aggregated at the 60-secondepoch length, all data points (counts) collected within a 1-minuteperiod are averaged.essential fat—Fat needed to maintain normal bodily functions. It isimportant for stored energy, cushioning and insulation, and vitaminabsorption; it is found in and around the nervous system, heart,lungs, kidneys, spleen, intestines, and muscles. The minimal amountof essential fat for men has been estimated to be 3% of body weight;for women the estimate is around 12% of body weight. Whenessential body fat falls too low, health risks for chronic disease andadverse immune reactions increase.excessive weight gain—A change in body weight of more than 2 kgper year or 10 kg per decade; or, a weight increase of more than 3percent.exercise—A specific type of physical activity that is planned,repetitive, and done for a specific purpose (e.g., to improve health orphysical function, physical fitness, or peak performance).exercise physiology—The study of how body structures andfunctions are altered by acute bouts of exercise or physical activity,and how the body adapts to the chronic stress of physical training.

experimental evaluation studies—A type of evaluation studydesign considered to be the gold standard of evaluation studies.These types of studies are characterized by randomization of peopleor communities to an intervention group (those that will receive thephysical activity program or policy) and control or comparison group(those that will not receive the physical activity program or policy).exposure—Any factor that is hypothesized or studied as beingcausally related to a defined outcome of interest.fasting plasma glucose (FPG) test—A test used to diagnosediabetes or prediabetes in which blood glucose is measured after aneight-hour fast. If the glucose level is 99 mg/dl or below, the test isnormal. A glucose level of 100 to 125 is consistent with prediabetesor impaired fasting glucose; a person with these levels is at higherrisk for type 2 diabetes. If the level is 126 or higher, the person hasdiabetes.Fitnessgram—A comprehensive set of assessment procedures forphysical education programs that includes health-related physicalfitness field tests that assess aerobic capacity; muscular strength,muscular endurance, and flexibility; and body composition.FITT—Frequency, intensity, time, and type (mode) of exercise.formative evaluation—The first level of a physical activity programevaluation, in which the fundamental questions focus on the needs,utility, and design features of a physical activity promotion programor policy and its individual components.functional ability—The capacity to perform a task, activity, orbehavior independently.functional health or physical function—The engagement inregular physical activity both individually and in populations, or tomove around and to perform types of physical activity. Measures ofphysical function include measures of ability to perform one’s desiredactivities of daily living like: walking (e.g., usually gait speed),running, climbing stairs, carrying groceries, sweeping the floor,standing up, and bathing.

geographic information systems (GIS)—Computational mappingmethods that allow for the analysis of geographic and social data(e.g., distances, landmarks, density, traffic, crime, resources, greenspace) by overlaying data in map format from multiple sources.Global Physical Activity Questionnaire (GPAQ)— Standardizedinternational surveillance instrument for physical activity, modeledafter IPAQ, its predecessor.GPS waypoints—Geographic location points recorded continuously(every 5 to 15 seconds) by Geographic Positioning Systems (GPS)monitors, which include data on latitude, longitude, date stamp, timestamp, and altitude, and from which travel velocity can be derived.gross energy expenditure—The combination of physical activity orexercise energy requirements with resting energy expenditure.health administration and policy—The field of public health thatfocuses on health care administration, leadership, and management.health education—Education that encompasses strategies toincrease or maintain personal health.health promotion—The process of enabling people to increasecontrol over, and to improve, their health. It moves beyond a focuson individual behavior towards a wide range of social andenvironmental interventions.health-related PE (HRPE)—A concept that promotes public healthobjectives and focuses on the health benefits of physical activity.Healthy People 2020—Health goals that are updated every 10years by the U.S. Department of Health and Human Services thathighlight disparities and opportunities for health improvement bysetting public health targets to achieve in a 10-year period.high intensity interval training (HIIT)—Physical activities orexercises that require working at a higher intensity for a few secondsor minutes followed by working at lower (recovery) intensities, whichcan vary in training bouts.

hypertrophy—The enlargement of an organ or tissue from theincrease in the size of its cells.ideal body fat/ideal body weight—An optimal percentage of bodyfat or value of one’s body weight that is highly variable and should bebased on factors such as age, sex, personal goals, behaviors, andappropriate educational messaging that does not promote addictivedisorders (i.e., eating or exercise).implementation fidelity—The extent to which the program or policyis being implemented as originally planned.incidence—a measure of disease frequency for the occurrence ofnew cases of a disease or outcome of interest over a specifiedperiod of time.individually adapted behavior change programs—Physicalactivity promotion strategies that integrate key components of thehealth behavior theories and theoretical models to help peoplechange and maintain physical activity behaviors. The evidence basebehind these types of programs is strong, and these strategies workwhen implemented appropriately.infectious diseases—Illnesses due to a specific infectious agent orits toxic products that arise through transmission of that agent or itsproducts from an infected person, animal, or reservoir to asusceptible host.informational approaches—Strategies designed to increasephysical activity that rely on the transmission of information.initiation (cancer)—The first stage of the multistage model ofcarcinogenesis. In this stage, genetic material is altered, andaffected cells are more likely to grow more rapidly than unaffectedcells.insomnia—Difficulty in sleeping at night.instrumental activities of daily living (IADLs)—Activities that aperson must be able to accomplish to live independently. Examplesinclude using a telephone, housekeeping, meal preparation, andlaundry.

insulin resistance—A condition in which cells become slow torespond or unresponsive to the effects of insulin, which gives themthe signal to absorb glucose from the bloodstream. Insulin resistanceis a risk factor for the development of diabetes.International Physical Activity Questionnaire (IPAQ)—Firststandardized international surveillance instrument for physicalactivity.interventions—A public health action, preferably at the communitylevel, designed to improve health.kinesiology—An academic discipline that addresses theinterrelationship of physiological processes and the anatomy of thebody with respect to movement.land use (zoning)—The management, planning, and developmentof land in defined jurisdictions.light-intensity activity—Activity requiring 1.6 to 3.0 METs, such aswalking at a slow pace (2 mph or less) or cooking.logic model—A critical tool for program evaluation in which agraphic or narrative description of processes and interrelationshipscan lead to a result (cause and effect). Logic models describe anddefine the relationships between resources, the target population,short-term and long-term effects, and the ultimate desired outcomesof a program or policy.macro-environmental urban design (also known as community-scale urban design)—The aspects of the built environment at alarge scale, usually spanning several square miles (or kilometers),and normally defined as an administrative unit like a neighborhood,zip code, school district, city, or county.magnetic resonance imaging (MRI)—A research and medicaldiagnostic tool that relies on X-ray technology to quantify the amountof fat tissue and other tissue in the body or in a region of the body.MRI is thought to be a safer technique largely because it does notrely on ionizing radiation.

maintenance stage—The fifth and final stage of the transtheoreticalmodel, in which a person has been consistently active for at least sixmonths.mass media campaign—The use of mass media channels todeliver messages about physical activity to large audiences. Massmedia campaigns are designed to increase awareness or knowledgeof the health benefits of physical activity, and are a type ofinformational approach that does not have enough evidence to berecommended by the Community Guide.MET—A metabolic equivalent or 3.5 ml . kg–1 . min–1 of oxygenuptake, which is equal to the resting energy expenditure for anaverage person.meta-analysis—A study compiling findings from the best studies ofa given topic and statistically combining these data findings todetermine strength of the evidence for that topic.metabolic syndrome—A cluster of clinical characteristics (withsimilar profiles in adults and adolescents) that include atherogenicdyslipidemia, elevated fasting glucose or insulin levels, hypertension,and excess abdominal obesity.metastases—The process by which a cancer spreads to organs andsystems other than their site of origin.micro-environmental urban design (also referred to as street-scale urban design)—The aspects of the built environment in smallgeographic areas, generally limited to a few blocks.moderate-intensity activity—Activity requiring 3.0 to less than 6.0METs, such as walking briskly (3 to 4 mph), mopping or vacuuming,or raking a yard.mood disorders—Psychological disorders that are characterized bychanges (increases or decreases) in a person’s mood (e.g.,depression).motor behavior—The study areas of motor learning, motor control,and motor development.

motor control—The study of human information processing and theintegration of motor movements that involve motor planning andexecution.motor development—The study of changes in motor behavior ofthe lifespan.motor learning—The study of how we learn and perform motorskills such as cycling and dancing. It also addresses the conceptsthat influence motor skills negatively or positively.movement sciences—The study areas of motor learning, motorcontrol, motor development, and biomechanics.multistage model of carcinogenesis—A useful model to study thedevelopment of cancer through three basic stages: initiation,promotion and progression.muscle dysmorphia—A psychological disorder characterized bynegative body image and the intense desire to have a muscularphysique.muscle mass—The bulk of skeletal muscle in the human body.musculoskeletal injury—An acute disorder in a bone, muscle, joint,or connective tissue that is attributable to exercise or physicalactivity.narcolepsy—A condition of extreme sleepiness during the day.National Physical Activity Plan (NPAP)—A comprehensive set ofpolicies, programs, and initiatives designed to increase physicalactivity in all segments of the U.S. population.natural environment—The physical aspects of the environment thatwere not created or altered by people. Examples include nationalparks, rivers, lakes, the ocean, or the weather.needs assessment—A source of data for formative evaluations withthe general purpose of gathering information from the targetpopulation (or one that is similar) of a planned physical activityprogram or policy.

net energy expenditure—Physical activity or exercise energyrequirement, or gross energy expenditure minus the resting energyrequirements.No Child Left Behind—An act passed by the U.S. Congress in2001 supporting standards-based education reform and includingprovisions for disadvantaged students.numerator monster—A mythical creature that arises when cases ofan outcome of interest are counted but the population from whichthose cases came from (the denominator) is not. Without thedenominator, following the numerator monster will lead to fallaciousconclusions about rates and risks.nutritional diseases—Nutrient-related conditions that causedisease in humans.obesity—Having an unhealthy body weight, which is consistent witha variety of disease processes such as CVD, metabolic syndrome,and type 2 diabetes.observational evaluation studies (often referred to as quasi-experimental designs)—A type of evaluation study design in whichpeople or groups are divided into treatment and control groupsbased on convenience, receptivity, targeting, and other factors.These types of evaluation study designs differ from experimentalones in that they are not randomized.oral glucose tolerance test (OGTT)—A test used to diagnosediabetes or prediabetes in which blood glucose is measured after aneight-hour fast and two hours after ingesting 75 grams of glucosedissolved in water. If the glucose level is 139 mg/dl or below, the testis normal. A glucose level 140 to 199 is consistent with prediabetesor impaired fasting glucose. If the level is 200 or higher, the personhas diabetes.osteoarthritis—The degeneration of joint cartilage and theunderlying bone, most common from middle age onward. It causespain and stiffness, especially in the hip and knee joints.

osteoporosis—A medical condition in which the bones becomebrittle and fragile from loss of tissue, typically as a result of hormonalchanges, or deficiency of calcium or vitamin D.outcome evaluation (also referred to as impact evaluation)—Astep of a physical activity program evaluation focused on cause andeffect. Outcome evaluation examines whether the program or policyhas the intended effect on the outcome of interest or not. For thepurposes of physical activity promotion programs and policies, theoutcome of interest usually refers to increased levels of physicalactivity due to the program or policy.overload principle—Improvement in health and physical fitness thatare directly related to increases in FITT variables by graduallyincreasing the physical stress on the body.overtraining—Participating in too much physical activity or exercisewithout taking the time to recover appropriately.overweight—Carrying more body fat than is healthy or an amountthat increases disease risk.partnership—The state of officially combining resources (people,finances) with one or more other entities or people to work toward acommon goal.physical activity—Any bodily movement that recruits skeletalmuscles and results in energy expenditure (i.e., expending calories).physical activity and exercise continuum—The process whereone should become physically active while avoiding sedentarybehaviors and seek to achieve specific health, physical fitness,and/or peak performance based on individual or population goals.physical activity energy expenditure (PAEE)—The energyexpenditure that is specifically the result of physical activity, usuallyexpressed as kilocalories.physical environment—A broad term encompassing all thephysical aspects of the environment that surround us. This caninclude the roads in a city or the lamp posts, but also topographicalaspects (e.g., steepness of a hill). There are two main types of

physical environmental features: those of the built environment andthose of the natural environment.physical fitness—A set of measurable physiological parameterssuch as cardiorespiratory endurance (aerobic power), skeletalmuscle endurance, skeletal muscle strength, skeletal muscle power,flexibility, balance, speed of movement, reaction time, and bodycomposition.place activation—Programming activities and communication orinformational strategies to get people to use a built environmentresource (e.g., a new park or trail).precontemplation stage—The first stage of the transtheoreticalmodel, in which a person has not even thought about becomingphysically active or may be unaware of the importance of beingphysically active.preparation stage—The third stage of the transtheoretical model, inwhich a person has reached that tipping point and is making smallchanges in behavior (e.g., taking the stairs rather than the elevator);in this stage, the person may be looking for support from friends andfamily as this new stage of activity begins.Presidential Youth Fitness Program—A comprehensive school-based program that promotes health and physical activity forAmerica’s youth. The program includes online challenges and allowsparticipants to keep track of their progress toward individual goals.prevalence—total number of individuals with a disease or outcomeof interest at a point or period in time (may be a health behavior, likeachieving sufficient levels of physical activity for health).process evaluation—A step of a physical activity programevaluation focused on implementation. The main interest whenconducting a process evaluation is to determine how well thephysical activity program or policy is operating and what can be doneto improve those operations.program evaluation—The process of collecting and analyzing datato determine if a program is necessary or feasible, if it is being

implemented optimally, if it is as impactful as intended, and if it iscost-effective.progression (cancer)—The third stage of the multistage model ofcarcinogenesis. In this stage, proliferating precancerous cellsbecome full, invasive tumors, and cancer is subsequently diagnosed.progression/adaptation—How the body (muscles, tissues, organsystems) reacts over time to overload and specificity in the context ofphysical activity and exercise.promotion (cancer)—The second stage of the multistage model ofcarcinogenesis. In this stage, initiated cells become precancerousthrough additional genetic changes as a result of the altered statethey entered in the first (initiation) stage. The promotion stage ischaracterized by rapid proliferation of altered cells.psychological distress (also known as mental distress)—A seriesof symptoms resulting from unpleasant emotions or feelings that canimpact someone’s overall level of functioning in everyday life.public health—The art and science of preventing disease,prolonging life, and promoting health through the organized efforts ofsociety.public health law—The part of public health that examines the roleof policy and government in promoting health and preventingdisease.public health surveillance—The ongoing, systematic collection,analysis, and interpretation of health-related data essential to theplanning, implementation, and evaluation of public health practices.quality of life—One’s satisfaction with life that includes health- andnonhealth-related aspects.random plasma glucose test—A test used to diagnose diabetes orprediabetes in which blood glucose is measured (nonfasting) when aperson has diabetic symptoms such as increased urination,increased thirst, unexplained weight loss, fatigue, blurred vision,increased hunger, or sores that do not heal. If the glucose level isabove 200 mg/dl, the person probably has diabetes.

randomization—The arbitrary assignment of people, groups ofpeople, or settings (e.g., schools or hospitals) to receive or notreceive an intervention or treatment.reactivity—The tendency to modify one’s habitual behavior afterbecoming aware that you are being measured or observed.recall bias—The inability to accurately recall, or the selective recallof only certain activities.relative intensity—The rate of energy expenditure as a percentageof maximum effort like the percent of O2max, percentage ofmaximal heart rate, or perception of effort on self-report scales.relative strength—The amount of force one can exert or the weightthey can lift for 1RM divided by their body weight.resistance training—Activities to improve strength, power, andmuscular strength and endurance such as weight training or usingflexible bands.response bias—When participants provide false or inaccurateresponses to questions.restless legs syndrome—A sleep movement disordercharacterized by the urge to move one’s legs while trying to fallasleep.risk factors—Lifestyle or genetic variables that can predict theoccurrence of disease.role ability—The ability to successfully perform both activities ofdaily living and instrumental activities of daily living.sedentary activity—Activity requiring 1.0 to 1.5 METs, such assitting and reading or watching television, or standing quietly.sedentary behavior—Any waking behavior characterized by anenergy expenditure of 1.5 or fewer METs while sitting, reclining, orlying. The majority of office work, driving a car, and sitting whilewatching television are examples of sedentary behaviors. Sedentarybehavior and sedentary activity are similar but not synonymous; both

are limited to energy expenditures 1.5 or fewer METs, but sedentaryactivity includes standing.self-efficacy—In a physical activity behavior context, it refers to theconfidence or perceived ability that a person may have to bephysically active and deal with the external threats and barriers thatcould result in slowing, stopping, or reverting progress.self-esteem—A general feeling of confidence and satisfaction withoneself.SHAPE America (Society of Health and Physical Educators)—Aprofessional organization promoting health and physical activity.skinfold measurement—Measurements of skinfold thickness atvarious sites on the body (e.g., the triceps, abdomen, and thigh) thatprovide an estimate of subcutaneous fat (about 50% of total bodyfat) and therefore an estimate of body density and the percentage ofbody fat.sleep apnea—A potentially serious disorder, characterized by upperairway blockage during sleep and resulting in the interruption ofbreathing during sleep.sleep disorders—Alterations in the way that one sleeps that affecthealth and quality of life.social capital—The factors that contribute to cohesive and well-functioning societies; elements of high social capital include a sharedsense of community and feeling that you can trust your neighbors.social desirability bias—Responding to a question based on whatyou feel others (including the interviewer) expect or consider good.social environment—A level of the socioecological model ofbehavior; it refers to how society is composed or how it behaves as awhole, beyond the people that we directly know or interact with in ourdaily lives.social support—A broad concept that generally refers to anystrategy for developing or strengthening the interpersonal

connections or the social environment of people to encourage (orovercome barriers to) physical activity.socioecological model of behavior—A conceptual framework andvisual representation for understanding the multiple factors thatinfluence physical activity, and therefore the potential solutions toencourage activity. The basic principle is that although the behavior(physical activity) occurs at the individual level, it is influenced byfactors of multiple levels (individual, interpersonal, socialenvironment, built environment, policy).SOFIT (system for observing fitness instruction time)—Avalidated direct observation tool for instructional settings thatmeasures both group-based levels of physical activity and quality ofthe class.SOPARC (system for observing play and recreation incommunities)—A validated direct observation tool for public openrecreation settings that measures both group-based levels ofphysical activity and environmental indicators of the social andphysical context of the settings.specificity principle—A principle based on the fact that changes inhealth and physical fitness are dependent on adjusting FITTvariables for the desired adaptations and outcomes.sport and exercise psychology—The study of behaviors andoutcomes related to participation in sports or programs of exercisetraining.stakeholders—People and organizations with direct or indirectinterests in a physical activity project, program, or policy.state anxiety—Acute feelings of stress due to confrontation with aspecific situation, place, or object.static (or isometric) physical activity or exercise—Physicalactivity that is anaerobic in nature and requires an increase in forceproduction with limited range of motion.thermic effect of food (TEF)—The amount of energy that is used todigest and metabolize energy that is ingested (food and drink).

Usually expressed as kilocalories.total energy expenditure (TEE), also referred to as total caloricexpenditure—The combination of one’s resting metabolism (basalmetabolic energy expenditure), thermic effect of food, and physicalactivity energy expenditure over time, usually expressed askilocalories.training plateaus—Training periods when little, if any, improvementoccurs with increased levels of physical activity or exercise.trait anxiety—refers to individual variations to state anxiety (seestate anxiety). Trait anxiety is a relatively stable aspect of apersonality, i.e., the differences in a person’s response to stressfulsituations, places, events, or objects.transtheoretical model—A theoretical model of health behavior,based on a five-category continuum of behavior, that is used toclassify how prepared a person is to change behavior, ormotivational readiness to change or begin.type 1 diabetes—A syndrome in which a person’s immune systemattacks and destroys the insulin-producing beta cells of the islets ofLangerhans in the pancreas.type 2 diabetes (adult-onset, non-insulin-dependent diabetesmellitus, or NIDDM)—A syndrome related to overweight, obesity,and insulin resistance (IR, impaired glucose homeostasis).underwater (hydrostatic) weighing—A technique that is based onthe principle of water displacement (i.e., when you get in tub ofwater, the water level rises based on the volume your bodydisplaces). In this technique, a person’s weight is measured both inand out of water. A person with more fat (which is less dense thanlean body tissue) will be buoyed up more than a leaner person, andwill consequently weigh less in water.urban design—The form, function, and outward appearance of thephysical environment in defined entities, such as neighborhoods,towns, cities, and communities.

vigorous-intensity activity—Activity requiring 6.0 or greater METs,such as walking very fast (4.5 to 5 mph), running, mowing grass witha hand-push mower, or participating in an aerobics class.volume—The dose of physical activity or exercise which is related tofrequency, intensity, type, and time/duration of physical activity.waist circumference—A measure of girth at the level of the lowestrib or umbilicus level using a cloth measuring tape with a spring-loaded handle; a common way to determine when people arecarrying too much abdominal fat for good health.waist-to-hip ratio (WHR)—A simple way to use circumferences toevaluate the distribution of body fat in adults. Health risk increasesas WHR increases, and standards vary by age and sex.walkability—A construct capturing the features of the builtenvironment of an urban area that are conducive to walking fortransportation. The most common definition of walkability combineshigh land-use mix, connectivity, and residential density, although thisdefinition is not necessarily applicable to all contexts and settings.weight maintenance (or weight stability)—A weight change ofless than 3%, and prevention of weight regain after a substantial lossthat is consistent with a change in weight of 3% to less than 5%.weight regain—after a substantial loss, it is consistent with achange in weight of 3% to less than 5%.Whole School, Whole Community, Whole Child (WSCC) Model—A public health framework that U.S. educators are encouraged touse to promote increased school physical activity that includeshealth education; physical education and physical activity; nutritionenvironment and services; health services; counseling,psychological, and social services; social and emotional climate,physical environment; employee wellness; family engagement; andcommunity engagement.

INDEX

Note: The italicized f and t following page numbers refer to figuresand tables, respectively.

Aabsolute intensity 26absolute strength 30academic performance 218academic programs, in public health 6ACC (American College of Cardiology) 85accelerometers 59-60, 59f, 69access to physical activity 242-243, 250accumulation of exercise 24ACSM (American College of Sports Medicine) 23action stage 226Active Australia (case study) 197, 197factive transport 243activities of daily living (ADLs) 138adaptation. See progression/adaptationaddictive behaviors 164ADLs (activities of daily living) 138adult-onset (type 2) diabetes 80, 90, 92f, 95adults and older adults. See also specific body systems or diseases

balance and stability in 137balance assessments 133basal metabolic energy expenditure 107benefits of physical activity in 38brain function outcomes in 169ffall risk reduction 137, 140, 141gait assessments 133physical activity guidelines for 48, 89t, 90, 118-120, 136-137, 137tquality of life 169resistance training in 126sarcopenia in 127waist circumference measures 116

adverse cardiac events 183-187, 185f

advocacy, of physical activity 9, 279-285, 281faerobic activities 24aerobic capacity 25, 139aerobic power 25affect 230age, as risk factor

brain health 165cancer 149CVD 82musculoskeletal disorders 126, 127musculoskeletal injury 181obesity 110

age-related cognitive decline 163, 170Aguilar, Nicolas 253AHA (American Heart Association) 85, 87air displacement plethysmography 115all-cause mortality 78-79, 79f, 88Alzheimer’s disease 163, 169, 170American College of Cardiology (ACC) 85American College of Sports Medicine (ACSM) 23American Heart Association (AHA) 85, 87anaerobic activities 24anaerobic capacity 25anaerobic power 25anatomical factors, in injury 181angiogenesis 167anorexia nervosa 164antismoking interventions 280-282anxiety disorders 163, 164, 170arthritis 124, 125, 126-127, 134-136assessment phase, of public health functions 10, 12fassessments. See fitness assessments; measurements of physical activity; program

evaluationassurance phase, of public health functions 10, 12fatherogenic dyslipidemia 80, 81, 83audits 248Austin, Texas (case study) 252, 252favailability, of geographic access 242AV O2 diff 83

Bbalance

assessment of 133fall prevention and 137functional health and 139

barriers, to physical activity 35, 227Barriers to Being Active Quiz 228f

basal metabolic energy expenditure (BMEE) 57, 107, 111Bauman, A. E. 196, 197bed rest, as detraining 35, 135, 135fBehavioral Risk Factor Surveillance System (BRFSS) 69, 70tbehavioral sciences. See also physical activity behavior

in history of physical activity and public health 44physical activity adaptations 82, 84-86, 113, 128, 130term usage 21youth and physical activity 209-210

behavior change. See physical activity behaviorBerg balance scale 133BIA (bioelectrical impedance analysis) 115Bills of Mortality 67bioelectrical impedance analysis (BIA) 115biomechanics, defined 20. See also movement sciencesbiostatistics 10Black Death (bubonic plague) 4-5blood glucose levels for active persons 97tBMD (bone mineral density) 124, 129, 133-134, 134f. See also musculoskeletal health and

disordersBMEE (basal metabolic energy expenditure) 57, 107, 111BMI (body mass index) 102-106, 103t, 104f, 105f, 112fBOD POD 115body composition

BMI and 103defined 107ideal 114measurement of 114-116, 114fyouth outcomes 211, 213

body fatabdominal 111essential 113ideal 114physical activity effects on 83, 107

body mass index (BMI) 102-106, 103t, 104f, 105f, 112fbody weight status 111. See also overweight and obesityBogota, Colombia (case study) 245bone mineral density (BMD) 124, 129, 133-134, 134f. See also musculoskeletal health and

disordersbone remodeling process 130fbone-strengthening activities 24, 134-135, 136-137, 137tbrain health and disorders

common conditions 163-164defined 162disorder prevalence and costs 162-163physical activity effects on 165-171, 166f, 169fphysical activity guidelines 173risk factors 164-165

testing for 168youth outcomes 213

breast cancer riskphysical activity and 146, 151, 157sex hormones and 153

BRFSS (Behavioral Risk Factor Surveillance System) 69, 70tBrownson, R. 11, 246, 247bubonic plague (Black Death) 4-5built environment

access to physical activity and 242-243, 250Bogota, Colombia (case study) 245defined 240influence of 49, 69, 242-243, 254land use policy 251measurement of 247-249Mueller neighborhood (case study) 252, 252fphysical activity policy and 249-251, 250fresearch challenges 243urban design 244-247walking trails development (case study) 246

bulimia 164

CCalise, T.V. 252, 276caloric balance 106-107, 106fcalories. See kilocaloriescalorimetry, indirect 57-58cancer

deaths from 147, 150tincidence of 148, 150tmetastases 146multistage model of carcinogenesis 148-149, 148fphysical activity among survivors 153-154, 154tphysical activity effects on 149-157physical activity guidelines 157prevalence and costs 146-148risk factors 149screening tests 153

cardiac events, sudden adverse 183-187, 185fcardiorespiratory fitness or function (CRF) 86-87cardiorespiratory health

assessment of 86-87general recommendations for 87-90physical activity effects on 82, 83-86, 84f, 88, 129physical activity guidelines 88-90, 89tyouth outcomes 209, 211, 213

cardiovascular disease (CVD)

defined 79London transport workers study 43-44, 44fphysical activity effects on 79-80prevalence and costs 80risk factors 79-80, 80-82secondary prevention of 85

careers in physical activity and public health 49-52. See also leader profilesCarlson, S.A. 183Centers for Disease Control and Prevention (CDC)

Physical Activity Evaluation Framework 260surveillance systems 46

Chau, J. 196, 197Chenoweth, D. 109, 109fchildren and adolescents

benefits of physical activity in 38BMI and weight status in 103-106, 104f, 105fbrain function outcomes in 169fdepression in 164developmental considerations 211, 212f, 217-218, 218fdiabetes in 80, 90fitness assessments of 210Let’s Move! initiative 195obesity prevention in 116, 118physical activity effects on 208-210, 211-213physical activity guidelines for 48, 89, 89t, 136, 137t, 213-214physical activity levels in 214-215self-report in 65waist circumference measures 116

cholesterol levels 80, 81, 83chronic diseases 6, 45church-based support network (case study) 235cigarette smoking. See tobacco usecitizen scientists 244clinically significant weight loss 111co-benefits, of physical activity promotion 254, 259, 270cognition 163cognitive function 163, 168-169collaboration partnerships 9, 276-277college-based health education (case study) 200colon cancer risk 146, 150-151, 152-153, 157combined physical movements 25commitment strategy 230tcommunication, of program evaluation results 270-272Community Guide 192-193, 215-216community interventions

Active Australia (case study) 197, 197fcommunity-wide promotions 194-196in public health practice 46-47

social support in 233-235West Virginia Walks (case study) 269

community-scale urban design 245-247compliance 23, 35-37Comprehensive School Physical Activity Program (CSPAP) 207, 216computed tomography (CT) 114connected support 229connectivity, in urban design 246consumer-based fitness trackers 62contemplation stage 226control groups 267-268cooperation partnerships 276coordination partnerships 276cost-effectiveness evaluation 263-264costs of disease. See economic costs of disease or injurycounts (accelerometer data) 59, 60C-reactive protein (CRP) 81-82CRF (cardiorespiratory fitness or function) 86-87crime, and physical activity 247-248CRP (C-reactive protein) 81-82CSPAP (Comprehensive School Physical Activity Program) 207, 216CT (computed tomography) 114cultural traditions, and obesity 111cut points

in accelerometer data 60for populations differences 103

CVD. See cardiovascular disease

Ddaily voluntary caloric expenditure 23data collection and analysis

for program evaluation 268-270surveillance data 46, 67-69, 70t

death. See mortalitydecisional balance 226-227delivery alternatives assessment 261dementia 163, 170, 171depression 163, 164, 170, 171detraining 23, 35diabetes

blood glucose levels for active persons 97tas CVD risk factor 81description and types 80physical activity effects on 91-92, 92f, 95physical activity guidelines 95-97prevalence and costs 90-91, 91frisk factors 91

tests for 93-94diagnosis, as public health function 10, 12fdiaries (self-report instrument) 64-65Dietary Guidelines for Americans (2015-2020) 18, 106diet interventions 111, 112fDing, D. 263Ding, Melody 236direct observation techniques 62-64, 248discretionary domain 56diseases. See also specific diseases

in history of public health 4-6physical activity and prevention of 19, 20f

distress 164, 165, 170, 170f, 171domains of physical activity 56, 58dose (volume) of exercise 23dose-response analysis

colon cancer 150described 24, 24f, 268metabolic syndrome 94, 94ftype 2 diabetes 92f

doubly labeled water technique 58dual-energy X-ray absorptiometry (DXA) 114, 114f, 133Dunn, A.I. 166, 232duration (time) of exercise 22, 30, 31tDXA (dual-energy X-ray absorptiometry) 114, 114f, 133dynamic physical activity or exercise 25dysthymia 164

Eeconomic access 242economic costs of disease or injury

brain and mental health disorders 162-163cancer 147-148CVD 80falls 138metabolic disease 90osteoarthritis 125osteoporosis 124overweight and obesity 108-109, 109f

economy of movementaerobic capacity and 25physical activity effects on 84weight loss or maintenance and 113in youth 209

effectiveness studies 47efficacy trials 46-47Ekelund, Ulf 201-202

electronic fitness devices 58-62, 59f, 60f, 61f, 66empowerment, in public health 9, 10, 12fendurance activities 136energy expenditure

by activity 107tage-related decline in 107calculations of (case study) 32, 32tcaloric balance and 106-107, 106fmeasurements of 23, 56, 57-58, 57f

environment. See also built environmentcancer risk and 146, 149defined 8influence on health 240-241influence on physical activity 49, 49f, 69, 242-243musculoskeletal injury risk and 181-182types 240

environmental health 8environmental health sciences 45epidemics 4-5epidemiology 6-7, 43, 45fepoch (accelerometer data) 59essential fat 113, 114estrogen 126, 153ethnicity. See race or ethnicityevaluations. See program evaluationevidence-based public health 193excessive caloric intake 110excessive weight gain 111exercise, defined 16, 56. See also physical activity and exerciseexercise/heart hypothesis 44exercise physiology

body composition adaptations 112, 113brain health adaptations 167cardiorespiratory adaptations 82, 83-86, 84f, 129defined 19metabolic adaptations 91-92musculoskeletal adaptations 128, 129youth outcomes 209

experimental design studies 266

Ffalls

economic costs 138low muscle mass and 127risk reduction 137, 140, 141

FAM (functional assessment measure) 139fasting plasma glucose (FPG) test 93

fat. See body fatFiatarone, Maria 126fibromyalgia 134Fick equation 83FIM (functional independence measure) 139fitness 16, 56, 181fitness assessments

balance 133body composition 114-116, 114fbrain health 168cancer screening 153cardiorespiratory fitness 86-87functional health 139-140gait 133musculoskeletal health 130-134, 133fobesity and overweight 113-116in school-based programs 210as training principle 22, 33-34

fitness devices 58-62, 59f, 60f, 61f, 66Fitnessgram 210FITT principles

frequency 30, 31t, 136intensity 25-30, 25f, 26t, 27f, 136, 167-168, 184, 185overview 22time (duration) 30, 31ttype 24-25

500 Cities Project 69food safety 43force development 129, 129fformal written policies 249formative evaluations 260-261, 266FPG (fasting plasma glucose) test 93fractures

osteoporosis and 126risk reduction 134, 135

frequency of exercise 22, 30, 31t, 136functional ability 138, 140-141functional assessment measure (FAM) 139functional health

assessment of 139-140concept of 137-138, 139fdefined 22, 137low muscle mass and 127physical activity effects on 140-141, 140fphysical activity guidelines 31t, 141risk factors 138-139

functional independence measure (FIM) 139funding, for public health partnerships 281

Ggait assessments 133genetics

as brain health risk factor 165as cancer risk factor 146, 149as CVD risk factor 82external influences on 81individual variation and 22, 31, 33fmusculoskeletal health and 126, 127as obesity risk factor 110

geographic access 242geographic information system (GIS) 248-249geographic positioning systems (GPS) 60-61, 60fgerm theory 4-5GIS (geographic information system) 248-249Global Matrix initiative 214-215Global Observatory for Physical Activity (GOPA!) 69Global Physical Activity Questionnaire (GPAQ) 68goals and goal setting 16, 17f, 22, 31Gomez, L.F. 245goniometry 133GOPA! (Global Observatory for Physical Activity) 69GPAQ (Global Physical Activity Questionnaire) 68GPS monitors 60-61, 60fgraded exercise testing (GXT) 86-87, 86fGRAD intervention (case study) 200green space 240grip strength assessment 132gross energy expenditure 23growth charts 103, 104f, 105fGuide to Community Preventive Services 192-193, 215-216

HHan, Ho 36-37handgrip dynamometry 132, 133fhealth. See also public health science; specific body systems or diseases

environmental 8, 240-241functional 22, 31t, 127, 137-141, 138f, 140f, 141obesity consequences 110physical activity effects on 24, 24f, 37-38poverty and 5

health administration and policy 9-10health belief model 225thealth education and promotion

classroom-based 198-202college-based (case study) 200defined 198

effective curricula 199overview 8-9as public health function 10, 12fWHO Principles of Health Promotion 9WSCC model 216

health guidelines development 47health-related PE (HRPE) 215health-related quality of life. See functional healthHealthy People 2020 108, 206, 207Heart and Soul program (case study) 235heart disease. See cardiovascular diseasehigh intensity interval training (HIIT) 24-25Hino, Adriano Akira 119hip fracture risk 134, 135HIV/AIDS 9-10Holloszy, John 94hormones, and osteoporosis 126household domain 56HRPE (health-related PE) 215hydrostatic (underwater) weighing 114-115hypertension 81hypoglycemia 95, 97

IIADLs (instrumental activities of daily living) 138ideal body fat 114ideal body weight 114impact (outcome) evaluations 262-263implementation fidelity 261-262inactivity. See physical inactivityinclusion, as health promotion principle 9indirect calorimetry 57-58individual factors in physical activity 48-49, 48f, 49findividually adapted programs 229-230, 230t, 232, 232findustrial revolution 5infectious diseases 4-6, 45inflammation biomarkers 81-82informational promotion

Active Australia (case study) 197, 197fclassroom-based health education 198-202community-wide campaigns 194-196mass media campaigns 196-198rationale for 194VERB (case study) 198

initiation stage of carcinogenesis 148injuries. See also musculoskeletal injuries

defined 178-179

risk of 25, 37, 209insomnia 164instrumental activities of daily living (IADLs) 138insulin-dependent (type 1) diabetes 80, 90insulin resistance 152, 153intensity of exercise

adverse cardiac events and 184, 185for brain health adaptation 167-168classifications of 25-26, 26tas FITT principle 22methods for determining 26-30, 27fof resistance training 136

O2 max and 25fInternational Physical Activity Questionnaire (IPAQ) 68intersectoral collaboration 9interval training 24-25interventions. See community interventionsinterviews, as physical activity measure 65IPAQ (International Physical Activity Questionnaire) 68isokinetic dynamometry 132isometric physical activity or exercise 25

JJáuregui de la Mota, Alejandra 283-284Jewell, J.S. 166Johns Hopkins School of Public Health 6joint injuries, and osteoarthritis 127juvenile (type 1) diabetes 80, 90

KKarvonen formula 27Katzmarzyk, P.T. 214-215kilocalories

caloric balance 106-107, 106fexcess intake 110needs formula 106per minute or hour intensity measure 28in physical activity measurement 32, 32t, 56total caloric expenditure 23

kinesiologybody weight and 112-113cancers and 149-153cardiorespiratory health and 82, 83-84, 84fdefined 17epidemiology merger 45fmetabolic health and 91-92

musculoskeletal health and 127-130, 129f, 130f, 131fmusculoskeletal injuries and 182-183subdisciplines of 18-21traditional training model 16, 17, 18fyouth outcomes 208-210

Kraus, William E. 96

Llactate threshold (LT) 83Laine, J. 263Lancet Series on Physical Activity 68land use policy 251law, public health 12-13leader profiles

Adriano Akira Hino 119Alejandra Jáuregui de la Mota 283-284Andrea Ramirez Varela 155-157Anna Porter 271-272Geoffrey P. Whitfield 72Ho Han 36-37I-Min Lee 50-51James Sallis 172-173Melody Ding 236Michael Pratt 186Nicolas Aguilar 253Peter Silvius 219Ross Brownson 11Sandra M. Mahecha 142Ulf Ekelund 201-202William E. Kraus 96

leadership 279, 280Lee, I-Min 50-51leisure-time domain 56Let’s Move! initiative 195Leutzinger, J. 109, 109flife expectancy 42lifestyle behaviors, and brain health 165light intensity 25logic model 264-266, 264f, 267fLondon School of Tropical Medicine and Hygiene 6London transport workers study 43-44, 44flow muscle mass 124, 127LT (lactate threshold) 83

MMcKenzie, Thom 63

macro-environmental urban design 245-247magnetic resonance imaging (MRI) 114Mahecha, Sandra M. 142maintenance stage 226male pattern fat distribution 111mass media campaigns 196-198maximal heart rate (MHR) 26-27, 83, 84fmaximal oxygen uptake. See O2maxmean anaerobic power (anaerobic capacity) 25measurements of physical activity

choosing method of 71, 71fcombined approaches 71direct observation techniques 62-64electronic devices for 58-62, 59f, 60f, 61f, 66laboratory techniques 57-58self-report instruments 64-67surveillance data 67-69, 70t

media campaigns 196-198medicine, versus public health 4mental health disorders. See brain health and disordersMET (metabolic equivalent) 23, 27-28, 32, 32tmeta-analysis (term) 151metabolic adaptations 91-92metabolic diseases. See diabetes; metabolic syndromemetabolic equivalent (MET) 23, 27-28, 32, 32tmetabolic health, in youth 211-213metabolic syndrome

assessment of 92-94as CVD risk factor 81described 80diagnosis criteria 91tphysical activity effects on 91-92, 94-95, 94fphysical activity guidelines 95-97prevalence and costs 90risk factors 91

metastases 146mhealth strategies 230MHR (maximal heart rate) 26-27, 83, 84fmicro-environmental urban design 244-245Mitchell, J. 35Mittleman, M.A. 185mobility limitations. See functional healthmobility tests 133mode (type) of exercise 22, 24-25moderate intensity 26modifications, as training principle 22, 34monitoring function, of public health 10, 12f

mood disorders 163-164, 170Moore, S.C. 78Morris, Jeremy N. 43-44, 44fmortality

cancer deaths 147, 150tleading causes of death 6, 6t, 46tphysical activity correlation 78-79, 79f, 88sudden cardiac death 183-187, 185f

motivation 22, 33motor behavior 20motor control 20motor learning 20movement sciences

adaptations in youth 209brain health adaptations 167cardiorespiratory adaptations 82described 20-21musculoskeletal adaptations 128, 129-130

MRI (magnetic resonance imaging) 114Mueller neighborhood (case study) 252, 252fmultidimensions, in health promotion principles 9multistage model of carcinogenesis 148-149, 148fmuscle dysmorphia 164muscle mass, low 124, 127muscle-strengthening activities. See resistance trainingmuscular strength and endurance 132, 139, 209, 211musculoskeletal health and disorders

assessment of 130-134disorder prevalence and costs 124-125fitness and function tests 133fmost common disorders 124physical activity effects on 127-130, 129f, 130f, 131f, 134-136physical activity guidelines 135, 136-137, 137trisk factors 125-127youth outcomes 209, 211, 213

musculoskeletal injuriesdefined 178-179incidence and prevalence of 179-180, 180t, 182fnumerator monster and 179physical activity effects on 182-183, 183frisk factors 180-183training principles and 184

Nnarcolepsy 164National Health and Nutrition Examination Survey (NHANES) 69, 70tNational Health Interview Survey (NHIS) 69, 70t

National Physical Activity Plan (NPAP) 206-207, 277-278National Physical Activity Society (NPAS) 21, 52National Public Health Performance Standards Program (NPHPSP) 10National Society of Physical Activity Practitioners in Public Health (NSPAPPH). See

National Physical Activity Societynatural environment 240needs assessments 261, 266negative lifestyle behaviors, and brain health 165. See also physical inactivity; sedentary

behavior and activityneighborhoods, defining 248net energy expenditure 23NHANES (National Health and Nutrition Examination Survey) 69, 70tNHIS (National Health Interview Survey) 69, 70tNIDDM (non-insulin-dependent diabetes) 80No Child Left Behind legislation 208noncommunicable (chronic) diseases 6, 45non-insulin-dependent (type 2) diabetes (NIDDM) 80NPAP (National Physical Activity Plan) 206-207, 277-278NPAS (National Physical Activity Society) 21, 52NPHPSP (National Public Health Performance Standards Program) 10NSPAPPH. See NPASnumerator monster 179nutrition

cancer and 149obesity and 111osteoporosis and 126public health goals 18

nutritional diseases 5

OOA (osteoarthritis) 124, 125, 126-127, 134-136Obama, Michelle 195obesity. See overweight and obesityobservational evaluation studies 266-268obstructive sleep apnea (OSA) 112, 164occupational domain 56occupational loads, and osteoarthritis 127OGTT (oral glucose tolerance test) 93older adults. See adults and older adultsOMNI-Walk/Run Scale 29, 30f1-repetition maximum (1RM) 29-30, 132, 133foral glucose tolerance test (OGTT) 93OSA (obstructive sleep apnea) 112, 164osteoarthritis (OA) 124, 125, 126-127, 134-136osteoporosis 124-126, 133-134, 134foutcome (impact) evaluations 262-263overload principle 22, 34, 184

overtraining 23, 35overweight and obesity

assessment of 113-116BMI and weight status 102-106, 103t, 104f, 105fcaloric balance and 106-107, 106fas cancer risk factor 149challenges of 111as CVD risk factor 81defined 102as disease 102health consequences 110as osteoarthritis risk factor 127physical activity effects on 112-113, 116-118physical activity guidelines 118-120prevalence trends and costs 107-109, 108f, 109frisk factors 109-111

PPAEE (physical activity energy expenditure) 57, 58, 107tPaffenbarger, Ralph 44, 44fPAGAC (Physical Activity Guidelines Advisory Committee Report)

benefits of physical activity 38cardiorespiratory health recommendations 88classification of physical activity 26, 26tas kinesiology and public health integration basis 18metabolic health recommendations 94-95mortality and physical activity correlation 78weight management 116-120

pandemic, of physical inactivity 68PAR (7-day Physical Activity Recall interviews) 64Parkinson’s disease 163participation, as health promotion principle 9partnerships

funding 281keys to building 277-278, 278tleadership strategies 279mobilizing 10, 12ftypes 276-277

peak power (anaerobic power) 25pedometers 61-62, 61fperceived exertion (PE) scales 29, 30fperceived support 227percentage of maximal heart rate 26-27percentage of maximal heart rate reserve 27percentage of maximal oxygen uptake 28, 29fperformance-related fitness 37PE (perceived exertion) scales 29, 30f

Peterson, J.A. 235physical activity advocacy 9, 279-285, 281fphysical activity and exercise

adaptations to. See progression/adaptationbarriers to 35, 227, 228fbenefits of 37-38, 45, See also specific body system or diseasesco-benefits from promotion of 254, 259, 270continuum of 16defined 16, 56in disease prevention and rehabilitation 19, 20fdomains of 56, 58energy expenditure calculations (case study) 32, 32texcessive, and osteoarthritis 127FITT principles 22, 24-30general guidelines 47-48, 56-57, See also specific body systems or diseasesguidelines for youth 48, 89, 89t, 136, 137t, 213-214as injury risk factor 181, 209measurements of. See measurements of physical activitymortality correlation 78-79, 79f, 88physician consult before 187promotion of. See built environment; informational promotion; school-based physicalactivity programstraditional training model 16, 17, 18ftraining principles 22-23, 31-37youth activity levels 214-215youth outcomes 208-210, 211-213

Physical Activity and Public Health Specialist 52physical activity and public health subdiscipline. See also public health science

careers in 49-52evolution of 42-45, 45f

physical activity behaviorfactors influencing 48-49, 49fHeart and Soul program (case study) 235individually adapted programs 229-230, 230tat population level 226Project Active (case study) 232, 232fsocial support for 227-229, 233-235theories and models of 224-227, 225t, 227f, 231-233, 231f

physical activity diaries 64-65physical activity energy expenditure (PAEE) 57, 58, 107tPhysical Activity Guidelines Advisory Committee Report (PAGAC). See PAGACPhysical Activity Guidelines for Americans

functional health guidelines 141general physical activity guidelines 47-48importance of 23as kinesiology and public health integration basis 18mortality and physical activity correlation 78muscle-strengthening activity guidelines 136-137, 137t

weight control guidance 106physical activity policy 249-251, 250fphysical activity programs. See program evaluation; school-based physical activity

programsphysical education 215-216physical environment 240physical fitness 16, 56, 181physical function. See functional healthphysical inactivity

as brain health risk factor 165as cancer risk factor 149as CVD risk factor 81emergence of public health issue 44as functional health risk 139health risks of 78-79musculoskeletal health and 125, 126-127, 134-135as obesity risk factor 110as pandemic 68

physiology. See exercise physiologypillars of public health 6-10, 7fplace activation 242policy development 9, 10, 12fpolicy influence

beyond physical activity 254on physical activity 69, 241-242, 249-251, 250fin social cognitive model 49, 49f

POM (Profile of Mood States) 168Porter, Anna 271-272poverty, and health 5Pratt, Michael 186precontemplation stage 226prediabetes tests 93-94premature death risk 78-79, 79fpreparation stage 226Presidential Youth Fitness Program 210President’s Council on Sports, Fitness, & Nutrition 210process evaluations 261-262Profile of Mood States (POM) 168program evaluation

co-benefits of 259cost of 263data collection and analysis 268-270design of 266-268importance of 258-259logic model for 264-266, 264f, 267fquestions in 262results dissemination 270-272steps in CDC framework 260

types 260-264, 260fwhen to begin 258

progression/adaptationbrain health 167-168cardiovascular 82, 83-86, 84f, 129genetics and 31, 33finjury prevention and 184metabolic 91-92musculoskeletal 127-130, 129f, 130f, 131fin overweight and obesity 112-113as training principle 23, 34-35in youth 208-210

progression stage of carcinogenesis 149progressive overload 22, 34, 184Project Active (case study) 232Project GRAD (case study) 200promotion of physical activity and exercise. See health education and promotion;

informational promotion; physical activity behaviorpromotion stage of carcinogenesis 148protective equipment use 181psychological distress 164, 165, 170, 170f, 171Public Health Functions Project 10public health guidelines 47-48public health law 12-13public health science. See also health

areas (pillars) of specialization 6-10, 7fdefined 42evidence-based 193focus of 4functions of 10, 12f, 46-47future of 13history and evolution of 4-6, 42-45subdiscipline 42-45, 45f, 49-52surveillance data 46, 67-69, 70ttraining programs 6

Qquality of life 169, 170f. See also functional healthquality of well-being scale (QWB) 139quasi-experimental designs 266-268questionnaires 65-67

Rrace or ethnicity

as CVD risk factor 82diabetes prevalence 90

obesity prevalence 108as obesity risk factor 110-111as osteoporosis risk factor 126

Ramirez Varela, Andrea 155-157randomization 266random plasma glucose test 93-94reactivity 62, 64recall bias 67received support 227-229recovery time 23, 35recreational domain 56Reger-Nash, B. 269rehabilitation, and physical activity 19, 20frelative intensity 26, 27frelative strength 30reminder strategy 230trepetitions, in resistance training 136research

environmental science challenges 243translating into practice 46-47, 272

resistance trainingadaptations to 128-130as anaerobic activity 24for frail older adults 126guidelines 136-137, 137tmusculoskeletal health and 134-135training variables in 30

response bias 67restless leg syndrome 164rheumatoid arthritis 134role ability 138, 140-141Routemaster bus 43fRoutemaster bus study 43-44running economy. See economy of movement

SSallis, James 172-173, 200, 217sampling rate 59sarcopenia (low muscle mass) 124, 127Schmid, T. L. 249-251, 250fschool-based physical activity programs. See also health education and promotion

activity integration practices 206, 216assessments in 210developmental considerations 211, 212f, 217-218, 218fphysical activity adaptations in youth 208-210physical education 215-216rationale for 206-208

SPARK program (case study) 217, 217fwhole-of-school approach 207, 208f

sedentary behavior and activitydefined 16as disease and mortality risk 78-79weight management and 118in youth 213

self-determination theory 225tself-efficacy 86, 227self-esteem 164, 165self-reports 64-67, 247-248self-reward strategy 230tsequencing, of media campaigns 1967-Day Physical Activity Recall (PAR) 64sex, as risk factor

brain health 165cancer 149CVD 82musculoskeletal disorders 126, 127musculoskeletal injury 181

sex hormones 126, 153SF-36 (long) and SF-12 (short) assessments 139SHAPE America (Society of Health and Physical Educators) 207Shilton, T. 279-282Silvius, Peter 219single-stream campaigns 194skinfold measurement 114f, 115sleep apnea 112, 164sleep disorders 164sleep improvement 86, 112-113, 169smartphone apps 62smoking. See tobacco usesocial capital 233social cognitive theory 225tsocial desirability bias 67social ecological model 48-49, 49f, 231-233, 231fsocial environment 243social influences on physical activity 49, 49fsocial justice 9social media marketing 196-198social norms, as policy influence 250social support 227-229, 230t, 233-235Society of Health and Physical Educators (SHAPE America) 207socioeconomic status, and obesity 111SOFIT (system for observing fitness instruction time) 63SOPARC (system for observing play and recreation in communities) 63SPARK program (case study) 217, 217fspecificity principle 22, 34, 184

sport and exercise psychology 21. See also behavioral sciencesSports, Play and Active Recreation for Kids (SPARK) 217, 217fstakeholders 260, 270state anxiety 164static physical activity or exercise 25step counters 61-62, 61fstreet-scale urban design 244-245strength training. See resistance trainingstress management 86stretching, and injury risk 183stroke volume, changes in 84fsubstance abuse 165substitution strategy 230tsudden cardiac death 183-187, 185fsuicidal thoughts 165sun exposure 149surveillance data 46, 67-69, 70tsystem for observing fitness instruction time (SOFIT) 63system for observing play and recreation in communities (SOPARC) 63

Ttai chi 137, 141talk test 29, 30ftarget heart rate (THR) 27Task Force on Community Preventive Services 192teaching models 22, 33, 33fTEE (total energy expenditure) 57-58, 57fTEF (thermic effect of food) 57testosterone, and osteoporosis 126tests. See fitness assessments; measurements of physical activitytheory of planned behavior 225ttheory of reasoned action 225tthermic effect of food (TEF) 57thinness, as osteoporosis risk factor 125THR (target heart rate) 27time, as barrier to exercise 194time (duration) of exercise 22, 30, 31ttobacco use, as risk factor

cancer 149CVD 81musculoskeletal injury 181osteoporosis 125

total caloric expenditure 23total energy expenditure (TEE) 57-58, 57ftoxic environmental exposure 149training

dose response 23, 24, 24f, 268

FITT principles 22, 24-30plateaus in 34-35principles of 22-23, 31-37, 184traditional model 16, 17, 18f

trait anxiety 164transportation domain 56transtheoretical model 224-227, 225t, 227ftrauma, as brain health risk factor 165type (mode) of exercise 22, 24-25type 1 (juvenile) diabetes 80, 90type 2 (adult-onset) diabetes 80, 90, 92f, 95

Uunderwater (hydrostatic) weighing 114-115underweight, as osteoporosis risk factor 125urban design 244-247, 252U.S. National Physical Activity Plan 206-207, 277-278U.S. Report Card on Physical Activity for Children and Youth 214-215

Vvaccine development 42VERB campaign (case study) 198vertical jump test 133fvigorous intensity 26, 184, 185vital statistics system 5

O2max (maximal oxygen uptake)aerobic power and 25in CRF assessment 86-87exercise intensity and 25fintensity as percentage of 28, 29fphysical activity effects on 83, 84f, 129

O2peak 86, 87fvolume (dose) of exercise 23. See also dose-response analysis

Wwaist circumference measures 83, 115-116waist-to-hip ratio (WHR) 116walkability 246-247Walk a Hound, Lose a Pound model 267fwalking trails development (case study) 246Wang, Y. 108way points, on GPS device 60wearable fitness devices 58-62, 59f, 60f, 61f, 66web-based media 196-198weight management 111-112, 112f. See also overweight and obesity

West Virginia Walks (case study) 269Whitfield, Geoffrey P. 72WHO (World Health Organization) 6, 6t, 9, 285whole-of-school approach 207, 208fWhole School, Whole Community, Whole Child (WSCC) model 216WHR (waist-to-hip ratio) 116Wingate anaerobic power test 133workload anaerobic method 30worksite physical activity access 250World Health Organization (WHO) 6, 6t, 9, 285written standards 250WSCC (Whole School, Whole Community, Whole Child) model 216

Yyouth. See children and adolescentsYouth Risk Behavior Surveillance System (YRBSS) 69

Zzoning and land use 251

ABOUT THE AUTHORS

Harold W. (Bill) Kohl, III, PhD, is a professor of epidemiology andkinesiology at the University of Texas Health Science Center atHouston and the University of Texas at Austin. At the University ofTexas Health Science Center, Dr. Kohl also serves as the associateregional dean for academic affairs and international health affairs atthe Austin regional campus.

In his recent efforts, he has concentrated on national andinternational physical activity surveillance and epidemiology issues,as well as program development and evaluation studies for thepromotion of school-based physical activity for children andadolescents. He is a fellow of the American College of SportsMedicine (ACSM) and the National Academy of Kinesiology, and hehas served as an elected trustee of ACSM. He is the founder andpast president of the International Society for Physical Activity andHealth and currently serves as the elected chair of the U.S. National

Physical Activity Plan Alliance. He has served in an editorial capacityfor several scientific journals and is editor emeritus of the Journal ofPhysical Activity and Health. He has published more than 200papers, chapters, and monographs in the scientific literature. In 2018he coauthored the textbook Foundations of Kinesiology.

Tinker D. Murray, PhD, is a professor emeritus and honoraryprofessor of international studies in health and human performanceat Texas State University in San Marcos. He earned his PhD inphysical education from Texas A&M University in 1984. His researchinterests include school-based and clinical-based youth physicalactivity and interventions with public health linkages for theprevention of obesity and diabetes, continuing educationopportunities for coaching education, and personal fitness andtraining applications related to exercise physiology.

From 1982 to 1984, Murray served as director of cardiacrehabilitation at Brooke Army Medical Center, where he was twicerecognized for his exceptional performance. He began his career atTexas State University (formerly Southwest Texas State), where heserved as the director of employee wellness from 1984 to 1988 anddirector of the exercise performance laboratory from 1984 to 2000.He was a volunteer assistant cross country and track coach at

Southwest Texas State from 1985 to 1988 and helped win three GulfStar Conference titles.

From 1985 to 1988, he was a subcommittee member for theGovernor’s Commission on Physical Fitness that developed the FitYouth Today program. He served as lecturer and examiner for theUSA Track and Field Level 2 coaching certification program from1988 to 2008 and as the vice chair of the Governor’s Commission onPhysical Fitness in Texas from 1993 to 1994. He worked with theTexas High School Coaches Association (THSCA) from 2003 to2013 as a facilitator with the Professional Development Cooperative,which promoted continuing education opportunities.

Murray is a fellow of the American College of Sports Medicine(ACSM) and is certified as an ACSM program director. He was atwo-time president of the Texas regional chapter of ACSM (1987 and1994). He served on the national ACSM board of trustees from 1998to 2001. In the fall of 2003, he was a guest researcher at the Centersfor Disease Control and Prevention (CDC) Division of Nutrition andPhysical Activity. He has been actively involved with the InternationalSociety for Physical Activity and Health (ISPAH) and has attendedseveral biannual meetings of the International Congress on PhysicalActivity and Public Health.

Murray retired from Texas State University in 2018 and wasnamed a professor emeritus and honorary professor of internationalstudies. He continues to remain physically active by cycling daily,jogging often, and lifting weights twice a week. He remainsacademically active by contributing to scholarly presentations andpublications that promote physical active lifestyles.

Deborah Salvo, PhD, is an assistant professor of public health atthe Brown School at Washington University in St. Louis, where she isa faculty scholar of the Prevention Research Center, the Center forDiabetes Translation Research, and the Institute for Public Health.Before this appointment, she held positions at the University ofTexas School Health Science Center in Austin, Stanford University’sPrevention Research Center, and the National Institute of PublicHealth of Mexico.

Salvo is a native of Mexico City, Mexico, and earned herbachelor’s degree in nutrition and food sciences from UniversidadIberoamericana. She earned her doctorate in biological andbiomedical sciences (nutrition and health sciences, public health andepidemiology track) from Emory University in 2013. Her interests liein understanding the role of built environment on physical activityand health, and in using this evidence to resolve global healthdisparities. Her work ranges from local projects to multisiteinternational consortia. She has expertise in using, improving, anddeveloping novel methodological approaches that combine physicalactivity and spatial epidemiological tools to address complexquestions on the effects of context on health. Throughout her career,she has facilitated and led international collaborations to support thegrowth of the field of physical activity and public health on a global

scale, with special emphasis on low- and middle-income countriesand populations.

Salvo is the current chair of the Council on Environment andPhysical Activity within the International Society for Physical Activityand Health. She is also part of the steering committee of the GlobalObservatory for Physical Activity, and she is an active member of theOur Voice Global Network. Salvo serves as associate editor forPreventing Chronic Disease, an official scientific journal of theCenters for Disease Control and Prevention. Throughout her career,she has served as technical advisor on physical activity and the builtenvironment for several agencies, including the Centers for DiseaseControl and Prevention, the Fogarty International Center within theNational Institutes of Health, the National Institute of Public Health ofMexico, and the World Health Organization. Salvo was a contributingauthor to the second series on physical activity published by TheLancet in 2016, which convened global experts to present the latestevidence of the important role of physical activity for public health.