## 4 Discussion  
This study investigates the association between body composition and muscle fitness parameters in young judokas. We examined key indicators of body composition, including fat mass, muscle mass, and lean body mass, alongside muscle fitness parameters such as muscular strength, endurance, and power. Our findings reveal significant associations between body composition and muscle fitness, underscoring the critical role of optimal body composition in the physical performance of young judokas. Given the sport's demand for explosive movements and sustained physical exertion, [PERSON] et al. [27] emphasize that physical and physiological characteristics, such as muscle mass and aerobic endurance, are critical for success in judo. However, it is well doc  
Figure 1: Relationship between muscle mass and various performance metrics. This figure shows the association between muscle mass and measures of explosive strength (panels (**A**–**D**)), isometric strength (panels (**E**–**G**)), and local muscular endurance (panels (**H**–**J**)). Each panel presents the observed data points and the fitted regression line with muscle mass as the predictor. The output statistics in each panel include R2 (coefficient of determination), F (F-statistic), \(p\) (\(p\)-value), \(\beta\) (beta coefficient), and t (t-value). umented that body composition plays a pivotal role in judo performance. [PERSON] et al. [28] found that lean body mass is a key determinant of performance, influencing both strength and specific physical fitness. This is supported by [PERSON] et al. [29], who demonstrated that accurate estimation and maintenance of optimal body composition in adolescent judokas are crucial for their development and competitive success. Further, body composition is critically important for performance in judokas due to its direct impact on strength, agility, endurance, and overall physical efficiency. Lean body mass, particularly muscle mass, generates the explosive power needed for throws, holds, and counter-movements intrinsic to judo. Studies such as those by [PERSON] et al. [28] have shown that judokas with higher lean body mass tend to perform better, as muscle strength is a significant predictor of success in this sport. Moreover, [PERSON] et al. [27] emphasized that judokas must balance muscle mass and minimal body fat to optimize performance. Our results revealed a notable association between muscle mass and measures of explosive strength, as evidenced by significant correlations in the CMJ (\(p\) = 0.023) and DJ (\(p\) = 0.026). These findings highlight the direct impact of muscle strength and explosive power on the competitive performance of elite judo athletes. The association between body composition and muscle fitness parameters in young judokas is underscored by several key studies, revealing intricate interdependencies that influence athletic performance. [PERSON] et al. [30] demonstrated a significant correlation between handgrip strength and body composition parameters, emphasizing the importance of muscle mass in enhancing grip strength, a critical component in judo performance. Similarly, [PERSON] et al. [28] identified body composition, particularly lean body mass, and specific physical fitness factors, such as strength and endurance, as crucial determinants for distinguishing performance levels among judokas. Furthermore, [PERSON] et al. [31] highlighted the variation in body composition and motor potential across different weight categories, suggesting that optimal body composition tailored to weight class can significantly impact an athlete's motor abilities and overall performance. These findings collectively suggest that targeted training and nutritional strategies focusing on improving body composition and specific muscle fitness parameters can substantially enhance the performance of young judokas.