The purpose of this study was to examine potential moderators of school-based physical activity interventions on cardiorespiratory endurance in primary school-aged children using meta-regression. An Internet search with several databases was employed, extracting school-based pediatric physical activity intervention studies published within the past 30 years. Studies were included if there was a control or comparison group, if the study sample included primary school-aged children, if the targeted outcome of cardiorespiratory endurance was objectively assessed, if the intervention was at least partially school-based, and if the effect estimate's variability was reported. An inverse-variance random effects meta-regression was employed using the primary predictors of component number (single component or multi-component) and intervention length using 20 extracted studies with 23 total effects. The overall pooled effect on cardiorespiratory endurance was statistically significant (Hedges' g = 0.30, 95% C.I.: 0.19⁻0.40; p < 0.001). Using random effects meta-regression, neither component number (b = ⁻0.09, 95% C.I.: ⁻0.40⁻0.23; p = 0.560) or intervention length (b = 0.001, 95% C.I.: ⁻0.002⁻0.004; p = 0.427) yielded a significant modifying effect on cardiorespiratory endurance. School-based physical activity interventions have a significant pooled effect on cardiorespiratory endurance in primary school-aged children. Component number and intervention length does not modify this effect, suggesting other sources for between-study heterogeneity.
Keywords: aerobic fitness; exercise; health; meta-analysis; youth.