## 2 Materials and Methods
### Evaluation of Muscle Force
\begin{table}
\begin{tabular}{l c c} \hline \hline
**Variables** & **SQS Score** & **CASQ Score** \\ \hline EGS Medium maximal muscle force (N) & \(-0.057\) & \(\mathbf{-0.475}\) \\ EGS Maximal muscle force (N) & \(0.022\) & \(-0.163\) \\ EGS Duration of maintained maximal muscle force (s) & \(-0.188\) & \(0.106\) \\ EGD Medium maximal muscle force (N) & \(0.224\) & \(-0.167\) \\ EGD Maximal muscle force (N) & \(0.099\) & \(-0.233\) \\ EGD Duration of maintained maximal muscle force(s) & \(0.165\) & \(\mathbf{0.478}\) \\ FGS Medium maximal muscle force (N) & \(0.041\) & \(0.022\) \\ FGS Maximal muscle force (N) & \(0.051\) & \(-0.346\) \\ FGS Duration of maintained maximal muscle force (s) & \(\mathbf{-0.478}\) & \(0.145\) \\ FGD Medium maximal muscle force (N) & \(0.237\) & \(-0.215\) \\ FGD Maximal muscle force (N) & \(0.124\) & \(-0.256\) \\ FGD Duration of maintained maximal muscle force (s) & \(0.013\) & \(0.199\) \\ SQS Score & \(\mathbf{1}\) & \(0.388\) \\ CASQ Score & & \(\mathbf{1}\) \\ \hline \end{tabular} The bold values are different from 0 with a significance level \(\alpha=0.05\).  
\end{table} 
Table 17: Pearson correlation between SQS, CASQ scores and muscle parameters of left and right knee extensors and flexors. \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Variables** & **EGS** & **EGS** & **EGS** & **EGD** & **EGD** & **EGD** \\ \hline EGS Medium maximal muscle force (N) & \(\mathbf{0}\) & \(\mathbf{<0.0001}\) & \(\mathbf{0.733}\) & \(\mathbf{<0.0001}\) & \(\mathbf{<0.0001}\) & \(\mathbf{0.338}\) \\ EGS Maximal muscle force (N) & & \(\mathbf{0}\) & \(0.842\) & \(\mathbf{0.000}\) & \(\mathbf{<0.0001}\) & \(\mathbf{0.358}\) \\ EGS Duration of maintained maximal muscle force (s) & & \(\mathbf{0}\) & \(0.759\) & \(0.631\) & \(0.127\) \\ EGD Medium maximal muscle force (N) & & & \(\mathbf{0}\) & \(\mathbf{<0.0001}\) & \(0.654\) \\ EGD Maximal muscle force & & & & \(\mathbf{0}\) & \(0\) & \(0.393\) \\ EGD Duration of maintained maximal muscle force (s) & & & & & \(\mathbf{0}\) \\ \hline \end{tabular} The bold values are different from 0 with a significance level \(\alpha=0.05\).  
\end{table} 
Table 18: \(p\)-values for Pearson correlation between muscle parameters of left and right knee extensors. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline
**Variables** & **EGS** & **EGS** & **EGS** & **EGD** & **EGD** & **EGD** \\ \hline EGS Medium maximal muscle force (N) & \(\mathbf{0}\) & \(\mathbf{<0.0001}\) & \(\mathbf{0.733}\) & \(\mathbf{<0.0001}\) & \(\mathbf{<0.0001}\) & \(\mathbf{0.338}\) \\ EGS Maximal muscle force (N) & & \(\mathbf{0}\) & \(0.842\) & \(\mathbf{0.000}\) & \(\mathbf{<0.0001}\) & \(\mathbf{0.358}\) \\ EGS Duration of maintained maximal muscle force (s) & & & \(\mathbf{0}\) & \(0.759\) & \(0.631\) & \(0.127\) \\ EGD Medium maximal muscle force (N) & & & & \(\mathbf{0}\) & \(\mathbf{<0.0001}\) & \(0.654\) \\ EGD Maximal muscle force (N) & & & & & \(\mathbf{0}\) & \(0.393\) \\ EGD Duration of maintained maximal muscle force (s) & & & & & \(\mathbf{0}\) \\ \hline \end{tabular} The bold values are different from 0 with a significance level \(\alpha=0.05\).  
\end{table} 
Table 18: \(p\)-values for Pearson correlation between muscle parameters of left and right knee extensors. We observe in Table 17 that the Pearson coefficients are less than 0.5, which means that there is weak correlation between muscle parameters on one side and the SQS and CASQ score on the other side. In Table 20 we observed that p values associated with correlation coefficients presented in Table 17 are below the threshold 0.05 only for good correlations. For these correlations, the Pearson coefficient is greater than the value 0.47. The good correlations are between the following pairs of variables: EGS medium maximal muscle force-CASQ, EGD duration of maintained maximal muscle force-CASQ, and FGS duration of maintained maximal muscle force-SQS.