Mediators effecting moderate-to-vigorous physical activity and inactivity for girls from an intervention program delivered in an organised youth sports setting

Objectives: The objective of this study was to test whether coaches' physical activity levels, contextual variables, and coaches' behavioural variables mediated the effect of an intervention on female basketball players' moderate-to-vigorous physical activity (MVPA) and inactivity in an organised youth sport (OYS) setting. Design: Randomised controlled trial. Methods: Data for the current study were derived from a two-armed, parallel-group randomised controlled trial. This study ran over the course of a 5-day OYS basketball program in 2 sports centres in Sydney, Australia. A convenience sample of 76 female players and 8 coaches were recruited. Coaches allocated to the intervention condition attended 2 coach education sessions, where strategies to increase MVPA and decrease inactivity were taught. Results: There was a significant effect between changes in coach MVPA and player MVPA (unstandardised regression coefficient [. B] = 0.26, 95% CI = 0.14 to 0.38) which coincided with a significant indirect effect (B = 1.80, 95% CI = 0.85 to 2.85). There was also a significant effect between changes in coach inactivity and player inactivity (B = -0.23, 95% CI = -0.14 to -0.31), which coincided with a significant indirect effect (B = -3.20, 95% CI = -0.14 to -0.31). No significant indirect effects were found for lesson context and coaches' behaviours variables. Conclusions: Coaches' MVPA and inactivity significantly mediated the effect of the intervention on player MVPA and inactivity, respectively. Consequently, coaches' physical activity levels appear to be important for influencing their players' physical activity levels.