The purpose of the study was to investigate the utility of various social-psychological variables for predicting intentions to engage in physical activity within a national population. More specifically, attitude, perceived behavioral control, and perceived social support measures were utilized to provide modified operationalizations of the theories of planned behavior and reasoned action in order to assess their relative utility for predicting physical activity intentions. Data from the Campbell's Survey of the Weil-Being of Canadians enabled the assessment of the predictive efficacy of the two models in the overall population, as well as in various population subgroups. The theory of planned behavior was found to account for a substantially greater percentage of the behavior intention variance (31%) than did the theory of reasoned action (15%). Further, the study provides some support for the utility of the theory of planned behavior for understanding the activity intentions of different population groups.
L.M. Wankel and W.K. Mummery are with the Faculty of Physical Education and Recreation at the University of Alberta, Edmonton, AB Canada T6G 2H9. T. Stephens and C.L. Craig are with the Canadian Fitness and Lifestyle Research Institute, 313-1600 James Naismith Drive, Gloucester, ON Canada K1B 5N4.