Associations between body composition and physical performance in Chinese male adults: a cross-sectional study

Background Body composition is a key determinant of health and physical performance, yet its association with multidimensional physical fitness in adult male populations remains insufficiently understood. This study aimed to investigate the relationships between body composition parameters and physical performance in Chinese adult men. Methods A total of 2,362 adult males were recruited from community-based fitness assessment programs in Hengyang, China. Body composition, including body fat percentage, fat mass, fat-free mass, and skeletal muscle mass, was measured using bioelectrical impedance analysis. Physical performance was evaluated through handgrip strength, vertical jump, push-ups, back strength, and estimated VO₂max. Associations were analyzed using Spearman correlation, principal component analysis (PCA), and multiple linear regression models. Results Higher body fat percentage was significantly associated with poorer performance in vertical jump, push-ups, and VO₂max (all p < 0.001), whereas skeletal muscle mass showed positive associations with strength-related outcomes, particularly handgrip strength ( β = 0.384, p < 0.001). PCA revealed distinct clustering between adiposity-related variables and performance indicators. Regression analyses indicated that skeletal muscle mass was the strongest predictor of strength, while body fat percentage and age were the main predictors of reduced aerobic capacity. BMI showed weaker and less consistent associations with physical fitness compared with direct body composition indicators. Conclusion Body composition was associated with physical fitness among adult men. Higher adiposity was related to lower physical performance, whereas greater lean mass was positively associated with strength outcomes. These findings support the value of body composition assessment for community health monitoring, but longitudinal studies are needed before causal conclusions can be drawn.