Automatic vs. rational motives for adolescent physical activity: an ecological momentary assessment study.

Objective: The current study seeks to examine rational motivational variables central to self-determination theory (i.e., perceived competence, family social support, friend social support, autonomous motivation, controlled motivation, and amotivation) as moderators of the relationship between automatic motives (i.e., momentary affective states, fatigue, and energy) and physical activity (moderate-to-vigorous physical activity and sedentary behavior). Methods: We conducted a 20-day ecological momentary assessment (EMA) study, in which 100 adolescents aged 13-18 years old were recruited locally February 2016 to March 2017 and were asked to indicate baseline social support, motivation, and competence for physical activity. Subsequently, participants wore an Actigraph accelerometer 24 h per day and answered EMA surveys assessing automatic motives 4 times per day using time-based signaling. Results: There was a significant interaction between within-person positive affect and amotivation as a predictor of moderate-to-vigorous physical activity (MVPA) ( Conclusions: Overall, findings from this study suggest that rational and automatic motives are intertwined and should be explored together as targets for physical activity intervention efforts.