Sex-specific age comparisons.

Physical fitness during adolescence is critical for health and sports participation, with sex-specific developmental trajectories influencing performance. The aim of this cross-sectional study was to examine sex differences in physical fitness among non-athletic adolescents aged 13–15 years and to provide reference values for fitness parameters across age and sex. We assessed 9,669 non-athletic adolescents (64% females) aged 13–15 years. Fitness tests included Sargent jump, standing long jump, 30m sprint, medicine ball chest throw, and 6-minute shuttle run. Interactions between sex and age were analyzed using two-way ANOVA, with effect sizes (Cohen’s d) and mean differences calculated between 13–15 years of age. Pearson correlation coefficients were used to examine relevant relationships, and were compared between sexes using Fisher’s r-to-z transformation. Significant sex-by-age interactions were observed for all fitness parameters (p