Psychosocial correlates of objectively measured in-school and out-of-school physical activity among Brazilian adolescents.

Physical activity is influenced by an interplay of time and setting, thus, the role of psychosocial factors on behavior is expected to vary across the day. This cross-sectional study identified the psychosocial correlates of time spent in physical activity during in-school (i.e., 08:00-11:59) and out-of-school (i.e., 12:00-22:00) time segments. The sample consisted of adolescents (7th to 9th grade) of two public schools in Florianopolis, Brazil. Accelerometer measured light-intensity (LPA) and moderate-to-vigorous-intensity physical activity (MVPA) were estimated. Psychosocial correlates of physical activity (i.e., outcome expectations, attitude, self-efficacy, support from parents, and support from peers) were self-reported. Linear mixed models were applied and interaction effects of gender and age were also analyzed. From a total of 194 participants, 138 and 112 provided in-school and out-of-school valid data, respectively. Outcome expectations were associated with out-of-school MVPA (β = 0.18; p = .006). Age interaction effects were observed for the associations between outcome expectations and out-of-school LPA (β = 0.21; p = .009) and between self-efficacy and out-of-school MVPA (β = 0.19; p = .009). In conclusion, psychosocial correlates were positively associated with out-of-school physical activity and the effects varied according to age. No psychosocial correlates were identified for LPA and MVPA performed during schooltime.