## 4 Discussion
\begin{table}
\begin{tabular}{c c c c} \hline
**Contact Time (ms)** & **AP Impulse (BWs)** & **Vert Impulse (BWs)** & **Jump Height (cm)** \\ \hline S1-S2 & 0.04 * & 0.01 ** & 0.03 * & 0.03 * \\ S1-S3 & 0.03 * & 0.01 ** & 0.03 * & 0.03 * \\ S2-S3 & & & & \\ \hline \end{tabular}  
* S1: Shoe outside with a friction coefficient of 0.80 \(\pm\) 0.05. S2: Shoe outside with a friction coefficient of 1.00 \(\pm\) 0.05. S3: Shoe outside with a friction coefficient of 1.20 \(\pm\) 0.05. A-P: anterior–posterior direction. Vert: vertical direction. BW: body weight.  
\end{table} 
Table 7: Significance identified by \(p\)-value obtained from ANOVA test associated with the full approach jump (*: significant, \(p\leq\) 0.05; **: highly significant, \(p\leq\) 0.01). which constitute 11 out of the 13 parameters selected in the current study. Notably, 9 out of the 11 quality parameters exhibit non-linear influences of the shoe outside friction coefficient on skill performance quality (Tables 2, 4 and 6). As the friction coefficient increases, both the defensive slide and the full approach jump exhibited faster execution and more powerful actions to various extents, as did the jumping height of the full approach jump. However, the positive influence diminished in seven parameters, suggesting a potential saturation point, where further increases in friction coefficient may not yield proportional improvements in skill quality. In the context of discussing injury risk, the outcomes associated with the two selected parameters, namely joint torques related to lateral cutting movement in defensive slide and crossover dribbling, present a controversial scenario. The results of the defensive slide present a nuanced narrative that challenges prevailing expectations, while the results of crossover dribbling follow the common expectation. Specifically, common expectations posit that a high shoe friction coefficient is linked to movement conditions that could heighten the risk of soft tissue injury [13; 14]. In the case of the defensive slide, a notable pattern emerges wherein an augmentation of the friction coefficient corresponds to a reduction in ankle torque (Tables 1 and 2), suggesting a potential mitigation of injury risk. However, given the infrequency of pure lateral movements in real-game situations, additional investigations are imperative to validate these findings, particularly in defensive slide in real-game situations that encompass a combination of medial-lateral and anterior-posterior components. This underscores the intricate nature of movements in real-game scenarios and implies that solely examining pure lateral movement may not offer a comprehensive understanding of injury risk factors. Subsequent studies focusing on game-like skill control are requisite to substantiate the potential risk reduction. Summarizing the discussions above, the current study aligns seamlessly with the open-control nature of basketball skills [10; 11], emphasizing the critical role of dynamic balance control in cutting, rapid deceleration, and jumping movements. Considering both skill quality and injury risk, only two out of the nine affected control quality parameters demonstrate that an increase in friction coefficient enhances skill quality without a concurrent increase in injury risk. This intriguing revelation prompts consideration for a trade-off strategy or optimization in selecting the optimal friction coefficient. With only three coefficient manipulations in the current study, the possible optimal value of the shoe outside friction coefficient may exist between 1.0 and 1.2, underscoring the necessity for further research to pinpoint this optimal range. Comparing these results with those available in the existing literature [7; 8; 9], the study significantly contributes to the relatively limited body of research investigating the specific influences of shoe friction coefficients on basketball skills.