Abstract
The complexity of student social adaptability development mechanisms in the context of physical education reform urgently requires in-depth exploration. Grounded in self-determination theory as the primary theoretical framework, supplemented by constructivist learning theory and social cognitive theory, this study constructed a multilevel SEM chain mediation model to examine the adaptive effects of physical education reform. Through a three-wave longitudinal tracking design, data were collected from 5,400 students in 180 classes across 36 middle schools in eastern, central, and western regions. Multilevel structural equation modeling techniques were employed to systematically examine the pathways through which perceived physical education reform practices are associated with social adaptability via cognitive appraisal, emotion regulation, and behavioral strategies. The study found that perceived physical education reform practices had a significant positive association with social adaptability, with a total effect of 0.52, of which indirect effects accounted for 73.1%. The complete chain mediation path effect value was 0.091, accounting for 23.9% of the total indirect effects. Multi-level analysis showed that the observed associations were significant at individual, class, and school levels, with the strongest aggregation effect at the class level, reaching 0.108. Cross-level moderation effect tests found that class cohesion and school sports culture respectively strengthened the cognitive-affective path and behavior-outcome path. The findings suggest that the observed associations may reflect a developmental sequence from cognitive restructuring to emotional adjustment to behavioral transformation, providing theoretical support and practical considerations for deepening physical education reform. Given the observational nature of this study, future experimental research is recommended to establish causal relationships. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40359-026-04321-y.