The "play gap": socioeconomic stratification in pediatric physical activity and its long-term health implications.

Physical inactivity in children and adolescents is not only a behavioral problem but also a manifestation of structural inequity. Across countries and within populations, opportunities for physical activity are unequally distributed by sex, socioeconomic position, disability status, neighborhood conditions, and access to supportive social and built environments. As a result, those with the greatest health needs often face the greatest barriers to participation. In this review, we synthesize recent evidence on the determinants of inequity in child and adolescent physical activity, assess the strengths and limitations of major policy levers, and examine emerging intervention strategies designed to improve reach, relevance, and sustainability. We argue that progress will depend on moving beyond universal but weakly implemented recommendations towards equity-oriented approaches that are context-sensitive, cross-sectoral, and accountable for implementation. Schools, financial support mechanisms, urban design, digital tools, and participatory models all hold promises. Still, their effects are constrained when policy ambition is not matched by delivery capacity or when interventions fail to address underlying social gradients. Future progress requires a shift from fragmented programmes to resilient systems that embed equity in design, prioritize disadvantaged groups, strengthen surveillance and evaluation, and position young people and communities as active partners in change.