Association between family sports environment and adolescent physical activity: the mediating role of basic psychological needs and the moderating role of academic stress

Rooted in the integration of Self-Determination Theory (SDT) and Conservation of Resources Theory (COR), this study aims to explore the associations linking family sports environment to adolescent Moderate-to-Vigorous Physical Activity (MVPA). Specifically, it examines the mediating role of basic psychological needs satisfaction and the conditional indirect effects of academic stress on this mediated pathway. A multi-stage hybrid sampling method was employed to recruit 523 adolescents (Mean Age = 15.23, SD = 1.76) from six secondary schools across Eastern, Central, and Western China. Participants completed the Family Sports Environment Scale, the Basic Psychological Needs in Exercise Scale, and the Adolescent Academic Stress Scale. Physical activity was objectively measured using ActiGraph GT3X+ accelerometers (valid wear time $$\ge$$ 4 days, including 1 weekend day). Parental education level and BMI were included as covariates. Data were analyzed using SPSS 26.0 and the PROCESS macro (Model 59). (1) Measurement model assessment confirmed satisfactory reliability and validity for all constructs. (2) Family sports environment was significantly and positively associated with adolescent MVPA ($$\beta$$= 0.15,$$p<.01$$), with basic psychological needs serving as a significant mediating pathway. (3) Academic stress was observed as a “dual-stage” moderator: it negatively moderated the first stage of the theoretically linked pathway (family environment $$\to$$ needs satisfaction), consistent with the resource depletion hypothesis; conversely, it positively moderated the second stage (needs satisfaction $$\to$$ MVPA), consistent with the compensatory coping hypothesis. Crucially, despite these opposing moderating effects, the overall indirect effect of family environment on MVPA remained robust and stable across low, medium, and high levels of academic stress. The findings suggest a complex homeostatic dynamic where the opposing moderating effects of academic stress counterbalance each other. While high stress may attenuate the perception of family support, it simultaneously amplifies the motivation to engage in physical activity when psychological needs are satisfied. These results highlight the potential resilience of family support as a resource for adolescent health behaviors.