The impact of an implementation intervention that increased school's delivery of a mandatory physical activity policy on student outcomes: A cluster-randomised controlled trial

Objectives: Assess the impact of an implementation intervention on student's physical activity, health-related quality of life (HRQoL) and on-task behaviour. Design: A cluster-randomised controlled trial. Methods: Following baseline 61 eligible schools were randomised to a 12-month, implementation intervention to increase teacher scheduling of physical activity, or a waitlist control. Whole school-day and class-time physical activity of students from grades 2 and 3 (similar to ages 7 to 9) were measured via wrist-worn accelerometers and included: moderate-to-vigorous physical activity, light physical activity, sedentary behaviour and activity counts perminute. Children's health related quality of life (HRQoL) and out-of-school-hours physical activity was measured via parent-proxy surveys. Class level on-task behaviourwasmeasured via teacher self-report surveys. Student and teacher obtained outcomes were measured at baseline and 12-month follow-up. Parent reported outcomes were measured at 12-month follow-up. Linear mixed models compared between group differences in outcomes. Differential effects by sex were explored for student and parent reported outcomes. Results: Data from 2485 students, 1220 parents and >500 teachers were analysed. There was no statistically significant between group differences in any of the outcomes, including accelerometer measured physical activity, out-of-school-hours physical activity, HRQoL, and on-task behaviour. A statistically significant differential effect by sex was found for sedentary behaviour across the whole school day (3.16 min, 95% CI: 0.19, 6.13; p = 0.028), with females illustrating a greater difference between groups than males. Conclusions: Only negligible effects on student physical activity were found. Additional strategies including improving the quality of teacher's delivery of physical activity may be required to enhance effects. (c) 2021 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.