# Relationship between Unilateral Leg Extension Strength and Dynamic Balance in Healthy Young Men
## 4 Discussion  
This study investigated the relationship between unilateral leg extension strength and dynamic balance in healthy young men. The study found that all balance performances, including the three-direction score and the composite score used in the dynamic test, had moderate, large, and very large correlations with the absolute and relative 1 RM strength scores. The results of the study show that the positive interaction between strength and dynamic balance is linear. Lower limb strength is a fundamental component of sensorimotor function that supports mobility. Thus, a decrease in strength for movement-related activities may be associated with an increased likelihood of falls and a decrease in performance [28]. [PERSON] et al. [29] found that lower limb maximum isometric strength scores were significantly correlated with Y Balance Test directions, and a stepwise multiple regression analysis showed that power output explained between 21.9% and 49.4% of the variance in the Y Balance Test. In another study, a positive linear relationship was found between the distance in the Y Balance Test and the strength of the knee extensors in the anterior, posteromedial, and posterolateral directions (\(r\) = 0.617, \(r\) = 0.599, and \(r\) = 0.565, respectively) [19]. In our study, the explained variance between 1 RM strength and dynamic balance seems to be compatible in this respect (21-57% explained variance). On the other hand, in some studies, one can find interesting results regarding strength and dynamic balance, which contradict our and many studies in the literature. For example, in a study examining the relationship between peak isometric torque of hip external rotation, abduction and extension, and Y-balance scores, it was found that only hip abduction was a predictor of the Y Balance Test score [30]. Furthermore, [PERSON] et al. [31] found an insignificant relationship between the isokinetic concentric force of the ankle, knee, and hip groups and the dynamic balance values. They reasoned that the variance was not large enough to detect the relationship. Nevertheless, it can be said that increased strength capacity has a positive effect on balance performance. [PERSON] et al. [32] investigated the effects of a planned six-week lower and upper extremity strength training programme on static and dynamic balance in young male athletes. The authors observed significant training results for improving dynamic balance in the anterior (4.3%), posterolateral (6.1%), and posteromedial directions (6.6%). It can therefore be said that strength-based training methods have a direct influence on dynamic balance performance. It can be mentioned that dynamic balance tests can also be a training strategy for strength development. [PERSON] et al. [33] found that electromyographic (EMG) activity of \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Variables** & \(r^{2}\) & **Adjusted \(r^{2}\)** & \(p\) Value \\ \hline Anterior & & & \\ \hline Absolute Strength & 0.574 & 0.560 & \textless{}0.001 \\ \hline Relative Strength & 0.433 & 0.415 & \textless{}0.001 \\ \hline Posterolateral (PL) & & & \\ \hline Absolute Strength & 0.366 & 0.346 & \textless{}0.001 \\ \hline Relative Strength & 0.221 & 0.196 & 0.006 \\ \hline Posteromedial (PM) & & & \\ \hline Absolute Strength & 0.342 & 0.321 & \textless{}0.001 \\ \hline Relative Strength & 0.217 & 0.196 & 0.006 \\ \hline Composite & & & \\ \hline Absolute Strength & 0.453 & 0.435 & \textless{}0.001 \\ \hline Relative Strength & 0.288 & 0.265 & 0.001 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results of the linear regression analysis for the unilateral leg extension strength and the results of the Y Balance Test. the Vastus Medialis (VM) muscle exceeded the recommended threshold of 40-60% for strengthening effects during the test used in three aspects of the Star Excursion Balance Test (SEBT).