Physical Activity Interventions
Mediating variable framework in physical activity interventions: How are we doing? how might we do better?

https://doi.org/10.1016/S0749-3797(98)00080-4Get rights and content

Abstract

Introduction: Behavioral science provides the foundation for physical activity interventions. The mediating variable framework is used to assess the status of physical activity interventions and the roles that are, or could be played, by behavioral theory.

Methods: Twenty-five physical activity intervention studies and 45 physical activity correlational studies were found in the literature, tabulated, and included in the analysis.

Results: Behavioral interventions for promoting physical activity have worked primarily when participants were motivated enough to volunteer or when a school-based physical education program changed. In most cases, behavioral or psychosocial theory accounted for 30% or less of the variability in physical activity behaviors. Most intervention studies do not measure mediating variables, and when they do, they do not systematically effect changes in all the mediating variables on which they are predicated.

Discussion: To increase the effectiveness of physical activity interventions, more physical activity research should focus on a better understanding of the predictors of physical activity and toward interventions demonstrated to effect change in these predictors of physical activity.

Conclusion: Changing the focus to basic behavioral and social science and mediator change research should provide a more systematic and cost-effective approach to increasing the effectiveness of physical activity interventions.

Section snippets

Intervention → behavior: how are we doing?

Table 1 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 presents a summary of 23 physical activity intervention studies. While attempting to increase physical activity is highly laudable, we need to critically assess how well we have done. These critical comments apply to our own work, as well as that of others, and the results are comparable to those found with other behaviors.35

The primary purpose of intervention

Mediating variable framework

Similar to a recent paper by Hansen and McNeal,36 this paper argues that: (1) interventions work by means of mediating variables; (2) current theoretical models from which mediating variables are obtained often do not account for substantial variability in the targeted outcomes; (3) interventions have not been shown to effect substantial change in the mediating variables; and, together, (4) these factors impose limits on the effectiveness of the interventions. As a result, priority should be

Mediating variables → behavior: what’s possible?

Within the mediating variable framework, the maximum possible relationship of mediating variables to behavior places a limit on the effect of an intervention on behavior. A review of the theoretical literature enables us to assess what the current maximum level of predictiveness might be. There have been several recent reviews of theoretical models predicting physical activity.40, 41, 42 Table 2 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67,

Interventions → mediating variables: are we changing what we need to change?

If we accept that interventions work through mediating variables, then the extent to which interventions have an impact on mediating variables places another limit on the extent to which an intervention can have an impact on behavior. Few of the research projects summarized in Table 1 measured mediating variables. The ones that did, tested either an effect of the intervention on the mediating variables15 or the relationships of change in the mediating variable to change in physical activity

Discussion

This brief review suggests two major reasons why interventions are not attaining desired levels of change in behavioral outcomes. First, current theories do not predict behavior or behavior change at high enough levels. Second, interventions are not substantially effecting change in the mediating variables.

The low predictiveness of theory for behavior (RM→B2) specifies the vital importance of theory in the behavior change process. Clearly, more basic behavioral and social science research on

Recommendations for research

To facilitate communication, behavioral and social science research (BSSR) can be grouped into theoretical, basic, mediator change, and interventional categories. Theoretical BSSR includes research on basic mechanisms of cognition, emotion, and behavior not ordinarily focused on the behaviors of interest to us (e.g., physical activity). Basic BSSR employs the concepts, methods, and measures of theoretical BSSR to understand the behavior(s) of interest. Mediator Change research tests methods for

Acknowledgements

The authors were funded during the writing of this paper by grants from NIH: CA61596. The authors appreciate the comments of many reviewers, including Len Epstein, Rod Dishman, and Bess Marcus.

References (95)

  • J.F. Sallis et al.

    A multivariate study of determinants of vigorous exercise in a community sample

    Prev Med

    (1989)
  • M.F. Hovell et al.

    Identifying correlates of walking for exercisean epidemiologic prerequisite for physical activity promotion

    Prev Med

    (1989)
  • J.F. Sallis et al.

    Explanation of vigorous physical activity during two years using social learning variables

    Soc Sci Med

    (1992)
  • N.H. Gottlieb et al.

    The relative influence of health beliefs, parental and peer behaviors and exercise program participation on smoking, alcohol use and physical activity

    Soc Sci Med

    (1986)
  • S.G. Trost et al.

    A prospective study of the determinants of physical activity in rural fifth-grade children

    Prev Med

    (1997)
  • N.H. Gottlieb et al.

    Sociocultural correlates of childhood sporting activitiestheir implications for heart health

    Soc Sci Med

    (1985)
  • K.D. Reynolds et al.

    Psychosocial predictors of physical activity in adolescents

    Prev Med

    (1990)
  • R.C. Stucky-Ropp et al.

    Determinants of exercise in children

    Prev Med

    (1993)
  • J.M. Zakarian et al.

    Correlates of vigorous exercise in a predominantly low SES and minority high school population

    Prev Med

    (1994)
  • T. Baranowski et al.

    Theory as mediating variableswhy aren’t community interventions working as desired?

    Ann Epidemiol

    (1997)
  • B.R. Flay

    Efficacy and effectiveness trials (and other phases of research) in the development of health promotion programs

    Prev Med

    (1986)
  • U.S. Department of Health and Human Services. Physical Activity and Health: A Report of the Surgeon General. Atlanta,...
  • D.N. Lombard et al.

    Walking to meet health guidelinesThe effect of prompting frequency and prompt structure

    HealthPsychol

    (1995)
  • K.J. Calafas et al.

    A controlled trial of physician counseling to promote the adoption of physical activity

    Prev Med

    (1996)
  • Castro CM, Sallis JF, Hickman SA, Lee RE, Chen AH. A prospective study of psychosocial correlates of physical activity...
  • R.V. Luepker et al.

    Community education for cardiovascular disease preventionRisk factor changes in the Minnesota Heart Health Program

    Am J Public Health

    (1994)
  • D.R. Young et al.

    Effect of community health education on physical activity knowledge, attitudes, and behavior

    Am J Epidemiol

    (1996)
  • J.D. Killen et al.

    Cardiovascular disease risk reduction for tenth gradersa multiple-factor school-based approach

    JAMA

    (1988)
  • B.G. Simons-Morton et al.

    Promoting children’s diet and physical activity among childrenresults of a school-based intervention study

    Am J Public Health

    (1991)
  • G. Parcel et al.

    School promotion of healthful diet and physical activityimpact on learning outcomes and self-reported behavior

    Health Educ Q

    (1989)
  • S.H. Kelder et al.

    Community wide youth exercise promotionlong-term outcomes of the Minnesota Heart Health Program and the Class of 1989 Study

    J Sch Health

    (1993)
  • T.L. McKenzie et al.

    Effects of a curriculum and inservice program on the quality of elementary physical education classes

    Res Q Exerc Sport

    (1993)
  • J.F. Sallis et al.

    The effects of a 2-year physical education program (SPARK) on physical activity and fitness in elementary school students

    Am J Public Health

    (1997)
  • R.V. Luepker et al.

    Outcomes of a field trial to improve children’s dietary patterns and physical activity. The Child and Adolescent Trial for Cardiovascular Health (CATCH)

    JAMA

    (1996)
  • E.J. Satone et al.

    Operational design and quality control in the CATCH Multicenter Trial

    Prev Med

    (1996)
  • K. Resnicow et al.

    Results of the Teach Well Worksite Wellness Program

    Am J Public Health

    (1998)
  • A.C. King et al.

    Long-term effects of varying intensities and formats of physical activity on participation rates, fitness, and lipoproteins in men and women aged 50 to 64 years

    Circulation

    (1995)
  • A.C. King et al.

    Group- vs. home-based exercise training in healthy older men and womenA Community-Based Clinical Trial

    JAMA

    (1991)
  • A.W. Garcia et al.

    Predicting long-term adherence to aerobic exercisea comparison of two models

    J Sport Exerc Psychol

    (1991)
  • J.I. Robison et al.

    Effects of a 6-month incentive-based exercise program on adherence and work capacity

    Med Sci Sports Exerc

    (1992)
  • A.C. King et al.

    Low cost strategies for increasing excercis behaviorrelapse preparation training and social support

    Behav Modif

    (1984)
  • B.H. Marcus et al.

    Evaluation of relapse prevention and reinforcement interventions to promote exercise adherence in sedentary females

    Res Q Exerc Sport

    (1993)
  • J.M. Jakicic et al.

    Prescribing exercise in multiple short bouts versus on continuous bouteffects on adherence, cardiorespiratory fitness, and weight loss in overweight women

    Int J Obes

    (1995)
  • P.A. Estabrooks et al.

    Effect of a stimulus control intervention on attendance at a university fitness center

    Behav Modif

    (1996)
  • R.C. Brownson et al.

    Preventing cardiovascular disease through community based risk reductionThe Bootheel Heart Health Program

    Am J Public Health

    (1996)
  • T. Baranowski et al.

    Theory as mediating variableswhy aren’t community interventions working as desired?

    Ann Epidemiol

    (1997)
  • W.B. Hansen et al.

    The law of maximum expected potential effectconstraints placed on program effectiveness by mediator relationships

    Health Educ Res Theory Pract

    (1996)
  • Cited by (715)

    View all citing articles on Scopus
    View full text