Bidirectional Associations Between Psychological States and Physical Activity in Adolescents: A mHealth Pilot Study.

Objective To understand the predictors and consequences of adolescent moderate-to-vigorous physical activity (MVPA) and sedentary behavior in nearly real-time. Methods Participants were 26 adolescents ( M age = 15.96, SD  = 1.56) who provided 80 self-reports of subjective states and continuous objective reports of MVPA and sedentary behavior over 20 days. Results Random effects were observed for all of the models with affect and feeling variables predicting MVPA. There was a negative fixed effect for within-person positive affect and sedentary behavior and the inverse association for negative affect. Within-person MVPA was a significant positive predictor of positive affect and energy. There was a random effect for within-person MVPA and fatigue. There was a significant random effect for within-person sedentary behavior predicting positive affect. Within-person sedentary behavior was a significant negative predictor of energy. Conclusions Findings highlight the importance of the intrapersonal nature of the associations among subjective states and physical activity.