## 4 Discussion  
This study examined the effects of the NHCT program on linear speed, change of direction, jump performance, and eccentric strength levels in young football players. After the eight-week NHCT program, the COD, CMJ, and eccentric strength levels of the football players in the training group significantly increased. In the control group, no significant improvement was observed in the athletic performance parameters. After NHCT training, the NHCBP of the players in the training group significantly decreased. This decrease indicates that players were able to contract more eccentric muscles against gravity. Based on the applied training protocol, the training group achieved a 25% increase in eccentric muscle strength. Studies on football that included NHCT protocols with varying sets and repetitions have reported an increase in hamstring strength [4, 22]. This finding is consistent with the results of our study and demonstrates the positive effect of the NHCT training program on muscles. Hamstring muscle strength is critical, as it has been shown to contribute significantly to injury risk. A previous prospective cohort study assessing the impact of hamstring muscle strength during the Nordic hamstring exercise indicated that eccentric hamstring strength is a key factor in the risk of hamstring strain injury [37]. Specifically, elongation of the biceps femoris (BF) muscle during NHCT alters the force-velocity and force-length relationships, which directly influence muscle function and mitigate muscle damage [37, 38]. Moreover, an 11% increase in BF muscle length was associated with an approximately 21% reduction in the incidence of hamstring injuries [37]. These findings align with other studies highlighting the importance of enhanced eccentric hamstring strength and increased BF length in preventing hamstring injuries [28, 39, 40]. Football involves high-intensity actions such as sprints, changes of direction, and jumping, which require a developed neuromuscular system [41, 42]. The improvement in  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \multicolumn{2}{c}{**TG (n = 20)**} & \multicolumn{2}{c}{**CG (n = 20)**} & \multicolumn{2}{c}{**ANOVA-\(p\)**} \\ \hline  & **Pre-Test** & **Post Test** & **Pre-Test** & **Post Test** & **Group\(\times\)Time Interaction** \\  & \(\vec{x}\pm\)**SS** & \(\vec{x}\pm\)**SS** & \(\vec{x}\pm\)**SS** & \(\vec{x}\pm\)**SS** & \(\vec{x}\pm\)**SS** & \\  & **ICC (95\%)** & **ICC (95\%)** & **ICC (95\%)** & **ICC (95\%)** & **ICC (95\%)** & **F** & \(p\) & \(\eta_{\mathrm{p}}\)\({}^{\mathbf{2}}\) \\ \hline CMJ (cm) & \(33.37\pm 2.12\) & \(39.50\pm 1.50\) & \(31.93\pm 2.06\) & \(33.19\pm 1.68\) & & & \\  & \(0.811\) (\%) & \(0.952\) (\%) & \(0.838\) (\%) & \(0.925\) (\%) & \(19.993\) & \(<\)0.001 \(\textasci{\textasci{\textasci{\textasci{\textasci{\textasci{\textasci  
COD and linear sprint performance observed in our study supports these findings [4; 43]. Studies have reported the contribution of NHCT to athletic performance by increasing the change of direction speed in young football players [43; 44; 45], but [PERSON] et al. [45] reported that low-volume NHC exercises do not affect linear sprinting. In our study, the effect on linear sprint may be due to the gradual increase in the intensity of NHC exercises. The findings of our study are consistent with these results, underlining the contribution of NHCT to neuromuscular development and performance increase. These findings reveal the necessity of adding NHCT to training programs, especially for sports such as football, which require speed and agility. It is known that modern football requires not only sprints and changes of direction, but also superiority in aerial balls. Success in aerial balls is directly related to the vertical jumping ability of players [46; 47]. NHCT improves jump performance by increasing the power-production capacity of these muscles. For instance, it has been reported that an 8-week NHCT program led to significant improvements in CMJ and squat jump performance [48; 49].