## 4 Discussion
The results of the current study also demonstrated that back extension (\(p\) = 0.006; R\({}^{2}\) = 0.61) and hand grip strength (\(p\) = 0.009; R\({}^{2}\) = 0.52) exhibit a strong positive association with muscle mass. This indicates that greater muscle mass significantly contributes to higher performance in these strength measures, underscoring the importance of muscular development in elite judo athletes. These results align with previous studies showing a significant correlation between body composition and strength, particularly explosive and isometric strength [32; 33]. A similar study on Polish national and international rank competitors found a statistically significant correlation between lean body mass and hand-grip strength [31]. In contrast, the tests of repetitive strength did not have a statistically significant correlation with the body composition of the competitors. This is in line with the results obtained in our study. The same research also found a correlation between absolute strength tests and body mass and body fat percentage. This justifies the fact that competitors from higher weight categories, who also have a higher body fat percentage, recorded better results in absolute strength tests. There is a significant impact of muscle mass % on DJ height, bench press throw Fmax, and absolute strength (back Fmax and hand Fmax). Muscle mass is one of the crucial determinants of performance in judo, significantly impacting an athlete's strength, power, and overall effectiveness in competition. According to [PERSON] et al. [34], muscle mass is particularly influential in young judo athletes, where somatic maturation, growth, and training experience collectively shape their physical capabilities. This study highlights that increased muscle mass can enhance physical performance metrics such as explosive and absolute strength. In judo, where the ability to execute powerful throws, maintain holds, and resist opponents' maneuvers is essential, greater muscle mass translates into more effective performance. Muscle mass contributes to higher levels of anaerobic power and muscular endurance, allowing athletes to perform explosive techniques repeatedly throughout a match without significant fatigue. Consequently, targeted training programs to increase muscle mass should be a fundamental aspect of judo training regimens, especially for developing athletes. However, this study is not without shortcomings. This study's cross-sectional design limits the ability to infer causality, and we can only discuss associations, not causal relationships, between body composition and muscle fitness parameters. The relatively small sample size may increase the likelihood of Type II errors, potentially underestimating the strength of associations between variables. Additionally, while participants were top-level athletes within their respective categories, the combined analysis of cadets and juniors without detailed differentiation could influence the findings. Furthermore, this study included only male judokas, limiting the generalizability of the findings to female judokas. This study did not account for the participants' nutritional habits, specific training regimens, or other lifestyle factors that could influence muscle fitness. Additionally, including various weight categories without specific analyses might obscure the weight class's potential differences and influences on the results. This oversight limits the granularity of our findings, as different weight categories may have distinct physical and physiological profiles that affect muscle fitness parameters differently. Moreover, the variability in the accuracy and precision of measurement techniques for body composition and muscle fitness parameters can affect the reliability of the results. Despite these limitations, this study has several strengths. One significant strength is the focus on young elite judokas, providing specific insights into this athlete population's body composition and muscle fitness.