Physical Activity Modulation in 9-11 year old children: Exercise Classes In the Teaching Environment (“EXCITE”)

Whether physical activity can be modulated via interventions is uncertain. PURPOSE: To determine whether a classroom-based intervention can modulate physical activity in 9-11 year old children. METHODS: We recruited a sample of 153 children (n=76 boys) from five schools. In an exploratory controlled before-and-after design, two schools were assigned to the Intervention condition (n=72) and three to Control (n=81), matching for socioeconomic status and physical education provision. School teachers delivered an 8-week classroom-based intervention, comprising of 10 minutes of moderate-vigorous physical activity integrated into the curriculum on each school day. Children in control schools maintained their usual school routine. Primary outcomes were the mean daily total physical activity (counts·min-1; cpm) and moderate-vigorous physical activity (minutes; Evenson cutpoints). We instructed children to wear a waist-mounted accelerometer for eight consecutive days, with a requirement for a minimum of four days with at least 10 hours of wear time. Measurements were taken at baseline, week 8 (during the last week of the intervention), and follow up (4 weeks post-intervention). We estimated the change from baseline for each primary outcome at week 8 and at follow up, including the baseline values as a covariate to adjust for any imbalance. We adopted a magnitude-based inferences framework, with the minimum important difference defined as a Cohen’s d of 0.2 standard deviations. RESULTS: At 8-weeks, the change from baseline in mean daily cpm in the intervention group versus control was 59 cpm (90% confidence interval, -20 to 138 cpm). The probability that the true population increase in cpm is larger than the minimum important difference was 0.75; “likely to be” practically important. For moderate-vigorous physical activity, the intervention resulted in a mean improvement of 10.1 minutes (-7.2 to 27.3 minutes). The probability that this effect was practically important was 0.64 (“possibly” beneficial). At follow up there were no substantial differences between intervention and control for either outcome. CONCLUSION: The short-term perturbation effect of the intervention on total physical activity was likely to be substantial. However, this effect was transient and practically disappeared at follow up.