Relationships among the theory of planned behavior, stages of change, and exercise behavior in older persons over a three year period

The present study examined the relationships among the theory of planned behavior (TPB), stages of change, and exercise behavior in 131 older persons over a three year period. Participants completed a baseline questionnaire by mail that assessed attitude, perceived control, subjective norm, intention, and stage and then received a telephone call three years later in which current exercise stage and behavior were assessed. Path analyses showed that (a) TPB constructs were significant predictors of exercise stage, (b) intention mediated the effects of TPB constructs on exercise stage, and (c) exercise behavior was best predicted by intention rather than stage. Results were interpreted as providing evidence for the long term predictive validity of TPB in the exercise domain and as questioning the necessity of combining both intention and stage in a single predictive model.