The theory of planned behavior as related to intention to exercise and exercise behavior

In a previously reported study we sought to assess the usefulness of the theory of planned behavior in explaining the exercise behavior of 73 adults enrolled in an exercise program over a 5-mo. period. The correlation between scores on Intention to Exercise and Exercise Behavior was moderate and inverse, conflicting with a primary tenet of the Theory of Planned Behavior. In this analysis of the data we sought to explain that finding by partitioning participants into groups based on a median split of their scores on Intention to Exercise and Exercise Behavior. Using the four Intention by Behavior groups as independent variables and scale scores as dependent variables, post hoc tests for Fitness Attitude showed significant differences only when High Intention conflicted with Low Intention, irrespective of Exercise Behavior. Perceived Behavioral Control showed opposite tendencies, i.e., differences were significant when High Behavior conflicted with Low Behavior, irrespective of Intention to Exercise. We conclude that Perceived Behavioral Control defines one's ultimate Exercise Behavior over a 5-mo. period while scores on Fitness Attitude define Intentions to Exercise.