Objective: The purpose of this study was to quantify the effect of physical activity (in both descriptive and intervention studies) on health-related quality of life (HRQOL) in children and adolescents from both healthy and chronic illness populations. Method: A systematic review of PubMed, PsycINFO, and ProQuest identified 33 studies of physical activity and HRQOL in youth, including descriptive and prepost intervention designs. Results: In descriptive studies (N = 14), there was a small, positive association between physical activity and HRQOL based on child-reports (Hedges' g = .302, p < .001, 95% confidence interval, CI [.178, .426]) and a negligible association based on parent-proxy reports (Hedges' g = .115, p = .101, 95% CI [-.023, .253]). Intervention studies (N = 19) yielded a small, positive effect of physical activity intervention on HRQOL based on child-reports (Hedges' g = .279, p = .014, 95% CI [.057, .500]) and a medium, positive effect based on parent-proxy reports (Hedges' g = .522, p = .012, 95% CI [.117, .928]). Intervention effects were attenuated by removal of a single study. Hypothesized and exploratory moderators did not moderate the relationship between physical activity and HRQOL. Conclusions: Findings supported the primary hypothesis that physical activity was related to better HRQOL in youth, although the magnitude of these effects did not represent a minimal clinically important difference (MCID) in most studies. Future studies are needed to assess HRQOL in youth before and after exercise interventions to quantify the type, frequency, duration, and intensity of physical activity needed to change HRQOL.
