Are Sex Differences in Youth Weightlifting Performance Explained by Fat-Free Mass? A Controlled Analysis

Bartkowiak, S, Kozieł, S, Krzykała, M, Karpowicz, K, Konarski, JM, and Malak, B. Are sex differences in youth weightlifting performance explained by fat-free mass? A controlled analysis. J Strength Cond Res XX(X): 000–000, 2025—This study examined sex differences in weightlifting performance among youth athletes, emphasizing the role of fat‐free mass (FFM), strength, and power. Fifty-three competitive weightlifters (28 male, 25 female) aged 13–15 years were evaluated using bioelectrical impedance analyses to estimate FFM, along with assessments of hand grip strength, squat jump (SJ) power, and isometric mid‐thigh pull force. Competition outcomes for the snatch, clean & jerk (C&J), and total weight lifted were recorded. Male weightlifters demonstrated significantly higher absolute strength outputs compared with female weightlifters ( p < 0.001). Regression analyses identified SJ power normalized to FFM as the strongest predictor of performance in male weightlifters across the snatch ( r 2 = 0.3742, p < 0.001), C&J ( r 2 = 0.3742, p < 0.001), and total ( r 2 = 0.3945, p < 0.001). In addition, results from the forward stepwise linear regression indicated that waist-to-hip ratio emerged as a significant, sex-specific predictor of C&J performance ( p > 0.05). These findings underscore the importance of FFM and lower-body explosive strength in youth weightlifting success. However, inherent neuromuscular and biomechanical differences between sexes contribute to persistent performance gaps. The results support the implementation of sex-specific training strategies that target these unique physiologic profiles to optimize performance outcomes in youth weightlifters.