The relationship between Body Mass Index and Physical Fitness Index among college students: a cross-sectional study in Yangzhou, China

Body Mass Index exhibits a distinct nonlinear relationship with physical fitness. College students with BMIs within the normal range demonstrate optimal physical fitness levels, while deviations from this range are associated with overall declines in physical fitness, particularly among male students. These findings provide a scientific basis for physical fitness monitoring and stratified intervention strategies for college students. However, due to the cross-sectional design of this study, causal relationships between BMI and physical fitness cannot be established, and future longitudinal studies are warranted.