The roles of want to commitment and have to commitment in explaining physical activity behavior.

BACKGROUND Several theories and models have been proposed to explain decisions in changing and adopting behavior but few address the intricacies of behavioral maintenance. The current study assesses the utility of the Investment Model, which identifies satisfaction, investments, and involvement alternatives as predictors of commitment and continued behavior, in predicting physical activity behavior. METHODS Participants (N = 267) completed questionnaires about physical activity and commitment. Structural equation modeling assessed relationships among 2 types of exercise commitment (want to or enthusiastic commitment, have to or obligatory commitment), 3 commitment determinants (satisfaction, investments, and alternatives), and physical activity (minutes of physical activity, stage of behavior change). RESULTS Want to commitment, but not have to commitment, was related to stage of exercise behavior change and time spent in physical activity. Satisfaction and investments were positively related to want to commitment; whereas, satisfaction, investments, and alternatives were positively related to have to commitment. The model explained 68% and 23% of the variance in time spent in physical activity and stage of behavior change, respectively. CONCLUSIONS This study provides support for the application of the Investment Model to physical activity and suggests that want to commitment may be important for explaining and predicting sustained physical activity behavior.