## 3 Results

Table 6: Descriptive statistics and ANOVA results for STIFF variable. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Measure**} & \multirow{2}{*}{**Side**} & \multicolumn{2}{c}{**PRE**} & \multicolumn{2}{c}{**POST**} & \multicolumn{2}{c}{**ANOVA Effects**} \\ \cline{3-8}  & & \(\mathbf{M\pm SD}\) & **Shapiro–Wilk** & **M \(\pm\) SD** & **Shapiro–Wilk** & **Time** & **Side** & **Time \(\times\) Side** \\ \hline \multirow{2}{*}{**MOS**} & \multirow{2}{*}{R} & 15.30 \(\pm\) 2.36 & \multirow{2}{*}{0.95 (0.28)} & 15.00 \(\pm\) 2.14 & \multirow{2}{*}{0.86 (0.01)} & \multirow{2}{*}{0.86 (0.01)} & \multirow{2}{*}{\(p\) = 0.010} & \multirow{2}{*}{\(p\) = 0.010} & \multirow{2}{*}{\(p\) > 0.05} & \multirow{2}{*}{\(p\) > 0.05} \\  & & (14.20, 16.40) & & & & & \\ \hline \multirow{2}{*}{L} & 15.20 \(\pm\) 1.94 & \multirow{2}{*}{0.94 (0.18)} & 14.00 \(\pm\) 1.07 & \multirow{2}{*}{0.95 (0.37)} & \multirow{2}{*}{0.95 (0.37)} & \multirow{2}{*}{0.95 (0.37)} & \multirow{2}{*}{\(p\) > 0.05} & \multirow{2}{*}{\(p\) > 0.05} \\  & & (14.30, 16.10) & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: _Cont._The analysis revealed no statistically significant effects (\(p>0.05\)) for all other variables. No meaningful changes over time, side-related differences, or interactions were observed. However, the DEC variable showed a significant effect for the Side factor in the between-side analysis for RF (\(p=0.031\); Figure 2b), indicating potential side-related differences in these measures. Despite some trends approaching significance, no conclusive differences were found for the remaining parameters. Figure 3: ANOVA visualization STIFF variables of (**a**) Achilles tendon, (**b**) Semitendinosus and (**c**) Rectus femoris. Group means (\(\pm\)SEM) and individual data points for STIFF variables are presented for PRE and POST time points, separated by Side (Left [L], Right [R]). Each subplot corresponds to a specific variable and tissue: (**a**) Achilles tendon, (**b**) Semitendinosus and (**c**) Rectus femoris. Data visualization includes individual data points and condition-specific means with standard error bars. The correlation analysis demonstrated significant relationships between VO2 max and several RF Pre viscoelastic properties (Figure 4). Specifically, VO2 max showed a moderate negative correlation with RF Pre FREQ (\(r=-0.60\), \(p<0.01\)) and RF Pre STIFF (\(r=-0.58\), \(p<0.01\)), indicating that higher aerobic capacity was associated with lower muscle frequency and stiffness. Conversely, VO2 max was positively correlated with RF Pre RT (\(r=0.53\), \(p<0.05\)) and RF Pre CREEP (\(r=0.48\), \(p<0.05\)). All other correlations between VO2 max and the examined variables were nonsignificant (\(p>0.05\)). Figure 4: Scatterplots for correlations assumptions. Scatterplots with regression lines and 95% confidence intervals displaying the relationship between VO2 max (mL-kg\({}^{-1}\cdot\)min\({}^{-1}\)) and various pre-intervention viscoelastic properties of the Rectus Femoris muscle. Each panel represents a bivariate correlation: (**a**) STIFF pre for [N/m], (**b**) RT [ms], (**c**) FREQ pre [H/z], (**d**) CREEP pre.