Heterogeneity manifestation and formation mechanism of school youth sports activity quality: a multi-case comparative study based on the configurational perspective.

Introduction: Improving school-based youth sports activities is an important objective of health and education policy, yet schools continue to differ markedly in implementation quality. Methods: This study combined multi-case comparison with fuzzy-set qualitative comparative analysis (fsQCA) to examine how policy, resources, organization, curriculum, teachers, facilities, evaluation, and student experience jointly shape activity quality. Five schools representing resource-driven, organizationally innovative, and resource-constrained contexts were analyzed. Results: Organizational leadership displayed quasi-necessary characteristics but was not sufficient alone. Eight high-quality and eight low-quality configurations were identified. High-quality outcomes reflected either the effective transformation of resource advantages or organizational compensation under moderate resources, whereas low-quality outcomes arose from weak foundational support or failures in organizational transformation. Student experience played a process-related role in several configurations. Sensitivity tests showed that the main explanatory structure remained broadly stable across the tested settings. Discussion: School youth sports activity quality is shaped by combinations of conditions rather than by a single factor. Given the five-school case base, the identified pathways should be interpreted as exploratory mechanisms within the examined schools rather than as estimates of their prevalence in a wider population.