Interventions for promoting physical activity among adolescents in school settings: systematic review and meta-analysis

Background Physical inactivity among adolescents is a significant challenge contributing to rising cases of obesity, noncommunicable diseases (NCD), and mental health challenges. A viable strategy is the promotion of physical activity (PA) in the school setting. We conducted a systematic review and meta-analysis to assess the efficacy of school-based physical activity interventions, compared to control conditions, in improving activity outcomes in adolescents. Methods We followed PRISMA guidelines and searched Scopus, Embase, CINAHL, PubMed, and Cochrane from 2000 onwards for relevant studies in English. We included randomised controlled trials (RCTs) involving adolescents aged 10–19 years with interventions in school-based settings and outcomes including activity, fitness, sedentary behaviours, and body mass index (BMI). We conducted a meta-analysis of included studies, assessed them using the Risk of Bias (ROB) 2 tool from the Cochrane handbook, and evaluated evidence quality through the GRADE framework. Results The search yielded 30629 records, of which 90 studies including approximately 17000 adolescents met the inclusion criteria. Interventions included multicomponent programmes, activity lessons, educational awareness sessions, and after-school activities. In the short term (0–6 months), school-based interventions significantly increased physical activity levels (standardised mean difference (SMD)=0.41, 95% confidence interval (CI)=0.23–0.59; low-certainty evidence). However, these improvements were not sustained beyond six months of follow-up, with pooled analyses showing no significant long-term effects on overall activity, sedentary behaviour, or BMI. Conclusions School-based interventions can modestly increase adolescents’ physical activity in the short term, but their effects diminish over time. Sustaining behavioural change may require long-term, system-level strategies that involve schools, families, and communities. Overall, the certainty of evidence was low to moderate, and findings should be interpreted with caution due to high heterogeneity across studies.