School-level variation in physical fitness outcomes among children and adolescents

Physical fitness is one of the key indicators of overall health in youth and plays an important role in decreasing the risk of a number of chronic conditions. There has been limited research on the relationship between school-level factors and young people's physical fitness, with no studies examining school-level variation in physical fitness outcomes for children and adolescents in Croatian schools. The primary aim of this article is to examine school-level variation in a number of health and performance/skill-related physical fitness outcomes. Specifically, we tested the following hypotheses: H1: When variation in physical fitness outcomes is partitioned across schools, counties, and regions, the largest contextual variation will be attributable to the school level; H2: School-level variation in physical fitness outcomes will remain substantial even after adjusting for individual-level covariates such as sex and class, and H3: School-level variation in physical fitness outcomes will be consistently high across both elementary and secondary schools. A total of 15,106 children and adolescents from elementary and secondary schools in Croatia participated in this study. They were tested in the following areas: body size, coordination, speed, agility, flexibility, strength, power and cardio. The multilevel analysis revealed that the largest contextual variation in physical fitness outcomes is attributable to the school level, underscoring the critical role that schools play in shaping students' physical fitness. Even after adjusting for individual-level covariates such as sex and class (grade), substantial variation between schools remained. Finally, we observed that school-level variation in physical fitness outcomes was consistently high across both elementary and secondary schools. The findings suggest that there is a need for comprehensive, multi-tiered interventions designed to guarantee that every student can access high-quality physical education and ample opportunities for physical activity.