## 3 Results  
The results regarding the biological maturation of the participants showed that, out of the total of 63 participants, 24 were in the stage of normal maturation, while the rest were all in the stage of early maturation. The characteristics of the youth football players are presented in the next table. The correlation analysis revealed significant relationships between the CMJ Bilateral Asymmetry Index and specific isokinetic strength variables. A significant positive correlation was observed between the CMJ Bilateral Asymmetry Index and the BAI Anterior Quadriceps (60\({}^{\circ}\)/s) (r = 0.262, \(p\) = 0.038, 95% CI [0.016, 0.479]), indicating a small-to-moderate effect size ([PERSON]'s z = 0.269, SE = 0.129). This finding indicates a modest but meaningful association between bilateral asymmetry and the anterior quadriceps performance at lower angular velocities. In contrast, a significant negative correlation was identified between the CMJ Bilateral Asymmetry Index and the BAI Posterior Hamstrings (60\({}^{\circ}\)/s) (r = \(-\)0.319, \(p\) = 0.011, 95% CI [\(-\)0.525, \(-\)0.077]), demonstrating a moderate inverse relationship ([PERSON]'s z = \(-\)0.331, SE = 0.129). This suggests that greater bilateral asymmetry in the CMJ is associated with reduced performance in the posterior hamstrings at this angular velocity. No significant correlations were found between the CMJ Bilateral Asymmetry Index and the other variables, including BAI Anterior Quadriceps at 180\({}^{\circ}\)/s (r = 0.138, \(p\) = 0.280, 95% CI [\(-\)0.114, 0.373]) and 300\({}^{\circ}\)/s (r = 0.121, \(p\) = 0.347, 95% CI [\(-\)0.131, 0.358]), or the BAI Posterior Hamstrings at 180\({}^{\circ}\)/s (r = 0.162, \(p\) = 0.205, 95% CI [\(-\)0.090, 0.394]) and 300\({}^{\circ}\)/s (r = \(-\)0.107, \(p\) = 0.404, 95% CI [\(-\)0.346, 0.145]). These findings indicate specific relationships between bilateral asymmetry and muscle performance at angular velocities of 60\({}^{\circ}\)/s, indicating distinct roles for the anterior quadriceps and posterior hamstrings (Table 3 and Figure 1). Moreover, a multiple linear regression analysis was conducted to explore the relationship between the CMJ Bilateral Asymmetry Index and the biomechanical predictors, including BAI Anterior Quadriceps (60\({}^{\circ}\)/s, 180\({}^{\circ}\)/s, 300\({}^{\circ}\)/s) and BAI Posterior Hamstrings (60\({}^{\circ}\)/s, 180\({}^{\circ}\)/s, 300\({}^{\circ}\)/s). The overall regression model (Table 3) was significant, F(6,56) = 2.42, \(p\) = 0.038, R\({}^{2}\) = 0.206, indicating that the predictors collectively explained approximately  
Figure 1: [PERSON]’s correlation matrix of CMJ Bilateral Asymmetry Index (BAI) and isokinetic variables across different angular velocities. The heatmap displays [PERSON]’s correlation coefficients (\(r\)) between the CMJ Bilateral Asymmetry Index and biomechanical variables, including BAI Anterior Quadriceps (60\({}^{\circ}\)/s, 180\({}^{\circ}\)/s, 300\({}^{\circ}\)/s) and BAI Posterior Hamstrings (60\({}^{\circ}\)/s, 180\({}^{\circ}\)/s, 300\({}^{\circ}\)/s). Significant correlations are indicated with \({}^{\star}\)\(p\)\(<\) 0.05, \({}^{\star\star}\)\(p\)\(<\) 0.01, \({}^{\star\star\star}\)\(p\)\(<\) 0.001. Warmer colors indicate positive correlations, while cooler colors represent negative correlations. \begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Variable** & **Pearson’s \(r\)** & \(p\) & **95\% CI Lower** & **95\% CI Upper** \\ \hline BAI Anterior Quadriceps (60\({}^{\circ}\)/s) & 0.262 * & 0.038 * & 0.016 & 0.479 \\ BAI Anterior Quadriceps (180\({}^{\circ}\)/s) & 0.138 & 0.280 & \(-\)0.114 & 0.373 \\ BAI Anterior Quadriceps (300\({}^{\circ}\)/s) & 0.121 & 0.347 & \(-\)0.131 & 0.358 \\ BAI Posterior Hamstrings (60\({}^{\circ}\)/s) & \(-\)0.319 * & 0.011 * & \(-\)0.525 & \(-\)0.077 \\ BAI Posterior Hamstrings (180\({}^{\circ}\)/s) & 0.162 & 0.205 & \(-\)0.090 & 0.394 \\ BAI Posterior Hamstrings (300\({}^{\circ}\)/s) & \(-\)0.107 & 0.404 & \(-\)0.346 & 0.145 \\ \hline \hline \end{tabular}  
* \(p\) \(<\) 0.05.  
\end{table}