The family, school and community linkage of improving adolescent physical fitness and health: based on the ANT.

Introduction: The issue of insufficient physical activity among adolescents is multifaceted and cannot be effectively addressed by a single organization or department. Therefore, cross-sectoral and inter-organizational collaboration offers a promising approach to meeting the complex needs of adolescents' early development and physical fitness promotion. Supported by Actor-Network Theory (ANT), this study systematically analyzes how urban China establishes a Family-School-Community (FSC)-centered network for promoting adolescent physical health. Methods: Through case studies, semi-structured interviews, and participant observations, the study identifies and captures the relationships and categories among various actors (both human and non-human), barriers and interest factors, network entry thresholds and sustainability conditions, as well as the alignment among participants, resources, and institutional support. Results: Qualitative analysis of the data reveals three core themes: (1) actor identification and determination, (2) network formation through translation, and (3) criteria for actor enrollment and mechanisms for resolving controversies. The findings indicate that cross-sectoral collaboration aimed at promoting adolescents' physical health is either largely absent or remains fragile, suggesting that local potential has not been fully leveraged. These results highlight the lack of effective actor recruitment within the network-building process. Conclusion: Consequently, it is essential to mobilize actors, policies, resources, and information exchange platforms to foster adolescents' participation in physical activities and to strengthen cross-sectoral cooperation policies and practices that support their healthy development.