School sport policy and school-based physical activity environments and their association with observed physical activity in middle school children

► School sport policies and their effect on children's physical activity were examined. ► Competitive varsity sports were associated with lower physical activity levels among boys. ► Intramural school participants were more likely to be boys and use indoor spaces. ► Physical activity settings were associated with higher activity levels among boys but not girls. ► Athletic facilities were under-utilized in all schools.