# Analysis of Surface EMG Parameters in the Overhead Deep Squat Performance
## 3 Results
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Group 1—Correctness of Deep Squat 23–54\%**} \\ \hline \multirow{3}{*}{**\%MVC**} & **Rectus** & **Vastus** & **Biceps** & **Gluteus** \\  & **Femoris** & **Medialis** & **Femoris** & **Muscle** \\  & **R = 28.000** & **R = 27.100** & **R = 12.600** & **R = 14.300** \\ \hline Rectus femoris & & 1.0000 & 0.0193 & 0.0527 \\ \hline Vastus medialis & 1.0000 & & 0.0333 & 0.0861 \\ \hline Biceps femoris & 0.0193 & 0.0333 & & 1.0000 \\ \hline Gluteus muscle & 0.0527 & 0.0861 & 1.0000 \\ \hline \hline \end{tabular}  
*—range average. RF—rectus femoris, VM—vastus medialis, BF—biceps femoris, GM—gluteus muscle. \(p\)-value (the level of probability \(p\)), the smallest level of significance for which the calculated value of testing statistic leads to rejection of null hypothesis after taking into account the correction for the number of comparisons.  
\end{table} 
Table 4: The results (\(p\)-values) of multiple comparison post hoc tests performed for the rectus femoris, vastus medialis, biceps femoris, and gluteus muscle in group 1 (correctness of deep squat 23–54%). The red color indicates pairs of muscles with significant statistical differences in excitation expressed in %MVC. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Group**} & \multirow{2}{*}{**Muscle**} & \multirow{2}{*}{**Size**} & **Rank** & **Rank** & \multicolumn{3}{c}{**Kruskal–Wallis**} \\ \cline{4-9}  & & & **Sum** & **Average** & **Test Value** & \(p\)**-Value** & **Effect Size (\(\eta^{2}\))** \\ \hline \multirow{4}{*}{1} & RF & 10 & 280 & 28.0 & & & \\  & VM & 10 & 271 & 27.1 & & & \\  & BF & 10 & 126 & 12.6 & & & \\  & GM & 10 & 143 & 14.3 & & & \\ \hline \multirow{4}{*}{2} & RF & 22 & 1263 & 57.4 & & & \\  & VM & 22 & 1484 & 67.5 & & & \\  & BF & 22 & 653 & 29.7 & & & \\  & GM & 22 & 516 & 23.5 & & & \\ \hline \multirow{4}{*}{3} & RF & 8 & 179 & 22.4 & & & \\  & VM & 8 & 193 & 67.5 & & & \\  & BF & 8 & 117 & 14.6 & & & \\  & GM & 8 & 39 & 4.9 & & & \\ \hline \hline \end{tabular}  
*—rectus femoris, VM—vastus medialis, BF—biceps femoris, GM—gluteus muscle. \(p\)-value (the level of probability \(p\)), the smallest level of significance for which the calculated value of testing statistic leads to rejection of null hypothesis. \(\eta^{2}\in(0,0.01)\)—very small effect size, \(\eta^{2}\in(0.01,0.05)\)—small effect size, \(\eta^{2}\in(0.06,0.13)\)—moderate effect size, \(\eta^{2}>0.14\)—large effect size [38].  
\end{table} 
Table 3: The results of the Kruskal–Wallis ANOVA rank test performed for the rectus femoris (RF), vastus medialis (VM), biceps femoris (BF), and gluteus muscle (GM) in individual groups 1–3. Figure 7 presents box plots for %MVC with division into deep squat level performance groups for all muscles concerned. \begin{table}
\begin{tabular}{l c c c c} \hline \hline  & \multicolumn{3}{c}{**Group 3—Correctness of Deep Squat 85-92\%**} \\ \hline \multirow{3}{*}{**\%MVC**} & **Rectus** & **Vastus** & **Biceps** & **Gluteus** \\  & **Femoris** & **Medialis** & **Femoris** & **Muscle** \\  & **R = 22.375** & **R = 24.125** & **R = 14.625** & **R = 4.875** \\ \hline Rectus femoris & & 1.0000 & 0.5908 & 0.0011 \\ \hline Vastus medialis & 1.0000 & & 0.2550 & 0.0002 \\ \hline Biceps femoris & 0.5908 & 0.2550 & & 0.2259 \\ \hline Gluteus muscle & 0.0011 & 0.0002 & 0.2259 \\ \hline \end{tabular}  
\end{table} 
Table 6: The results (\(p\)-values) of multiple comparison post hoc tests performed for the rectus femoris, vastus medialis, biceps femoris, and gluteus muscle in group 3 (correctness of deep squat 85–92%). The red color indicates pairs of muscles with significant statistical differences in excitation expressed in %MVC. Figure 11: Cont.