Self-Efficacy, Decision-Making, and Stages of Change: An Integrative Model of Physical Exercise1


  • 1

    This research was partially supported by Grant SO7RRO5818 from the National Institutes of Health, Grants KO7CAO1757, R29CA59660-01 and POICA50087 from the National Cancer Institute and Grant MH47233 from the National Institute of Mental Health. The authors wish to thank Elaine Taylor, Nancy Keenan and Mark Morgenstern for their efforts on this project.

Correspondence concerning this article should be addressed to Bess H. Marcus, Ph.D., Division of Behavioral Medicine, The Miriam Hospital and Brown University School of Medicine, RISE Building, 164 Summit Avenue, Providence, RI 02906.


Exercise has important health benefits but a large proportion of the population is physically inactive. We examined the stages of readiness to exercise and their relationship to self-efficacy, the costs and benefits of exercising, and self-report of physical activity in a sample of Rhode Island worksites. Using a three-step model-building approach, exploratory principal components analyses were followed by an examination of the stages of change model with confirmatory structural equation modeling procedures. The model was then examined with longitudinal data. Confirmatory and longitudinal analyses showed an excellent tit between the model and the data. Results indicated that the costs and benefits of exercise and self-efficacy for exercise were related to physical activity only indirectly, through the mediation of stage of readiness to exercise. Structural modeling fit indices revealed that much of the variation and covariation in physical activity was explained by the model. There is the potential to enhance the impact of exercise interventions, by targeting them so as to address factors related to these different stages of readiness.