## 4 Discussion  
The aims of the present study were (a) to investigate the trunk and lower body muscle strength, flexibility and postural control between participants with and without PFP, (b) to investigate the differences between the \"affected\" and \"non-affected\" leg in the PFP group and (c) to investigate possible correlations between the occurrence of PFP and leg dominance. Our first conclusion is that all trunk muscle strength outcomes are significantly impaired both in participants with uni- and bi-lateral PFP compared to participants without PFP. Our results are in concordance with previous studies reporting that participants with PFP exhibit 24-29% lower trunk lateral flexion strength compared to participants without PFP [13, 45]. However, both of these studies included participants with bilateral symptoms and therefore lacked further analysis on the \"affected\" and the \"non-affected\" leg compared with the matched side in the CG. Our study classifies participants with PFP based on their (more) affected leg and therefore provides a deeper insight into side-specific impairments. Our study demonstrated that only participants with unilateral PFP exhibit excessive contralateral pelvic drop, which may be linked to impaired trunk lateral flexion strength of the affected side in participants with PFP [7]. Accordingly, we demonstrated that \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Outcome Measure**} & \multicolumn{2}{c}{**Means \(\pm\) SD**} & \multicolumn{2}{c}{**Difference**} & \multicolumn{2}{c}{**Means \(\pm\) SD**} & \multicolumn{2}{c}{**Difference**} \\ \cline{2-11}  & \begin{tabular}{c} **Unilateral** \\ **PFP** \\ **(r = 12)** \\ \end{tabular} & \multirow{2}{*}{\begin{tabular}{c} **Control** \\ **(r = 37)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **\(p\)** \\ **ES** \\ \end{tabular} } & \multicolumn{2}{c}{**Bilateral PFP**} & \multicolumn{2}{c}{**Control**} & \multirow{2}{*}{\begin{tabular}{c} **\(\mathbf{t}\)** \\ **(r = 6)** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **\(\mathbf{t}\)** \\ **(r = 37)** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **\(\mathbf{p}\)** \\ **ES** \\ \end{tabular} } \\ \hline Hip flexion with knee & & & & & & & & & & \\ flexed (\({}^{\circ}\)) & 145.34 \(\pm\) 8.44 & 144.58 \(\pm\) 10.68 & 0.26 & 0.793 & 0.08 & 143.57 \(\pm\) 5.81 & 144.58 \(\pm\) 10.68 & \(-\)0.23 & 0.822 & 0.11 \\ Hip extension (\({}^{\circ}\)) & 29.57 \(\pm\) 11.01 & 28.86 \(\pm\) 10.02 & 0.24 & 0.811 & 0.07 & 31.28 \(\pm\) 13.24 & 28.86 \(\pm\) 10.02 & 0.53 & 0.602 & 0.21 \\ Trunk lateral flexion & & & & & & & & & & \\ diff (cm) & 24.33 \(\pm\) 5.89 & 23.37 \(\pm\) 4.27 & 0.69 & 0.490 & 0.19 & 26.17 \(\pm\) 4.93 & 23.37 \(\pm\) 4.27 & 1.46 & 0.152 & 0.60 \\ CoP sway path A-P & & & & & & & & & & \\ (mm) & 5.01 \(\pm\) 1.44 & 5.55 \(\pm\) 1.46 & \(-\)1.29 & 0.201 & 0.37 & 4.98 \(\pm\) 1.95 & 5.55 \(\pm\) 1.46 & \(-\)1.09 & 0.325 & 0.33 \\ CoP sway path M-L & & & & & & & & & & \\ (mm) & 5.95 \(\pm\) 2.24 & 6.60 \(\pm\) 2.43 & \(-\)0.95 & 0.343 & 0.28 & 5.89 \(\pm\) 2.22 & 6.60 \(\pm\) 2.43 & \(-\)0.85 & 0.352 & 0.30 \\ CoP sway velocity & & & & & & & & & & \\ A-P (mm/s) & & & & & & & & & & & \\ CoP sway velocity & & & & & & & & & & & \\ M-L (mm/s) & & & & & & & & & & & \\ Standing asymmetry & & & & & & & & & & & \\ index (\%) & 3.77 \(\pm\) 3.67 & 3.21 \(\pm\) 2.56 & 0.66 & 0.510 & 0.18 & 3.11 \(\pm\) 2.95 & 3.21 \(\pm\) 2.56 & 0.58 & 0.611 & 0.04 \\ Semi-Squad & & & & & & & & & & \\ asymmetry index (\%) & 4.70 \(\pm\) 2.23 & 3.87 \(\pm\) 2.32 & 1.26 & 0.212 & 0.37 & 4.54 \(\pm\) 2.02 & 3.87 \(\pm\) 2.32 & 0.98 & 0.204 & 0.31 \\ \hline \hline \end{tabular}  
CoP = Center of Pressure. \({}^{\star}\) Statistically significant difference.  
\end{table} 
Table 5: _Cont._participants with unilateral PFP exhibit lower trunk extension alongside impaired trunk lateral flexors compared to participants without PFP.