School-level correlates of physical activity intensity in 10-year-old children

Purpose. Little is known about school environmental factors that promote or inhibit activity, especially from studies using objective measures in large representative samples. We therefore aimed to study associations between activity intensities and physical and social school environmental factors. Methods. A population-based sample of 1 908 British children (SPEEDY study), mean age 10.3 years (Standard deviation [SD]: 0.3), recruited from 92 schools across Norfolk, UK, with valid activity data (assessed with Actigraph accelerometers). Outcome measures were school-based (8 am-4 pm on weekdays) time (in minutes) spent in sedentary (<100 counts/min), moderate (2000-3999 counts/min) and vigorous (>= 4 000 counts/min) activity. A total of 40 school physical and social environmental factors were assessed. Multivariable multilevel linear regression analyses adjusted for children's sex and body mass index were conducted; interactions with sex were investigated. Results. Availability of a 'Park and Stride' scheme was negatively associated with sedentary minutes (-7.74; 95% CI: -14.8; -0.70). Minutes of moderate activity were associated with the availability of a lollypop person (1.33, 95% CI: 0.35; 2.62) and objectively-assessed walking provision (1.70, 95% CI: 0.85; 2.56). The number of sports facilities of at least medium quality (0.47, 95% CI: 0.16; 0.79), not having a policy on physical activity (-2.28, 95% CI: -3.62; -0.95), and, in boys only, provision of pedestrian training (1.89; 95% CI: 0.77; 3.01) were associated with minutes of vigorous activity. Conclusions. Only a small number of school-level factors were associated with children's objectively-measured physical activity intensity, giving few pointers for potential future intervention efforts. Further research should focus on using objective measures to elucidate what factors may explain the school-level variance in activity levels.