Physical activity automaticity, intention, and trait self-control as predictors of physical activity behavior - a dual-process perspective.

Dual-process theories assume that physical activity (PA) behavior is regulated by two different processes: (i.e., automatic, fast) and (i.e., effortful, slow) processes. In this study we examined main effects as well as the interaction of reflective (intention and trait self-control)and impulsive (automaticity)processes on PA behavior. A prospective study with two points of measurement ( = 118 university students) was conducted. At t1, age, sex, past PA behavior (control variables), PA intention, automaticity and trait self-control (predictors) were assessed with standardized questionnaires. At t2 (4 weeks later), PA behavior (dependent variable) was measured with a standardized questionnaire. Hierarchical multiple linear regression analysis revealed that automaticity was associated with PA behavior. The expected interaction effects Intention x Trait Self-control and Automaticity x Intention x Trait self-control on PA were significant. Moderation analyses revealed that PA intention has a significant positive association with PA behavior when trait self-control was higher compared to lower. Furthermore, automaticity has the strongest association with behavior when both intention and trait self-control where lower compared to higher. Our results underline the additive and interactive effects of impulsive and reflective processes in regulating PA behavior.