Interdependent Effects of Autonomous and Controlled Regulation on Exercise Behavior.

Self-determination theory (SDT) is used to predict individual differences in goal-directed behavior. A fundamental tenet of SDT is that autonomously regulated behavior is more likely to be engaged in and sustained than externally controlled behavior. Unidimensional treatment of regulation is suboptimal. The current study utilizes a multidimensional approach-polynomial regression-to evaluate the interdependent effects of autonomous and controlled regulation on physical activity. Results from three samples of healthy, younger adults demonstrate a mostly positive influence of autonomous regulation but a curvilinear effect of controlled regulation on behavior such that greater activity was associated with moderate levels of controlled regulation-an effect that cannot be identified with "unidimensional" methods. Results from Sample 3 showed that autonomous regulation was associated with greater exercise levels only when controlled regulation was moderate or high. Results suggest that controlled regulation is not wholly detrimental to behavioral promotion.