## 4 Results
### Muscle Activation and Co-Activation  
The muscle activation of the semitendinosus, rectus femoris, medial gastrocnemius, vastus medialis, vastus lateralis, and tibialis anterior showed significant differences with the gradual increase in the foot external rotation angle at touchdown. The results of the statistical parametric mapping (SPM) analysis are shown in Figure 6. In terms of semitendinosu activation, post hoc analyses showed that, during the stance phase (26-37%, \(p=0.018\)), there were no significant differences between the TI and the TN and between  
Figure 5: Detailed results of joint angles and peak moments for different initial contact foot progression angles (20\({}^{\circ}\), 0\({}^{\circ}\), and \(-\)20\({}^{\circ}\)) at foot strike. The results of SPM analysis for TI, TN, and TO conditions are shown. The yellow, blue, and red areas correspond to the results of the SPM analysis for TI vs. TN, TN vs. TO, and TI vs. TO. F* is a specific threshold to distinguish between significant and non-significant regions. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Variables**} & **Toe-In** & **Toe-Neutral** & **Toe-Out** & \multirow{2}{*}{**\(p\)-Value**} & \multirow{2}{*}{**F**} & \multirow{2}{*}{**ES**} \\  & **Mean \(\pm\) SD** & **Mean \(\pm\) SD** & **Mean \(\pm\) SD** & & \\ \hline Ankle Dorsiflexion Angle (\({}^{\circ}\)) & 22.66 \(\pm\) 3.10 & 19.04 \(\pm\) 4.53 & 12.56 \(\pm\) 4.21 & \textless{}0.001 * & 55.75 & 0.717 \\ Hip Flexion Angle (\({}^{\circ}\)) & 53.42 \(\pm\) 7.95 & 56.06 \(\pm\) 9.91 & 55.83 \(\pm\) 11.84 & 0.074 & 3.041 & 0.019 \\ Knee Flexion Angle (\({}^{\circ}\)) & 50.39 \(\pm\) 5.97 & 51.40 \(\pm\) 4.87 & 54.50 \(\pm\) 3.84 & 0.02 * & 3.046 & 0.16 \\ Ankle Sagital Moment (Nm/Kg) & 3.95 \(\pm\) 0.37 & 3.61 \(\pm\) 0.45 & 3.12 \(\pm\) 0.55 & 0.023 * & 45.22 & 0.72 \\ Ankle Horizontal Moment (Nm/Kg) & 1.23 \(\pm\) 0.41 & 1.34 \(\pm\) 0.43 & 1.56 \(\pm\) 0.48 & \textless{}0.001 * & 22.76 & 0.778 \\ Knee Sagital Moment (Nm/Kg) & 1.71 \(\pm\) 0.63 & 1.92 \(\pm\) 0.47 & 2.12 \(\pm\) 0.52 & 0.009 * & 3.586 & 0.135 \\ Knee Frontal Moment (Nm/Kg) & 0.23 \(\pm\) 0.13 & 1.04 \(\pm\) 0.43 & 1.69 \(\pm\) 0.72 & \textless{}0.001 * & 49.04 & 0.743 \\ Knee Horizontal Moment (Nm/Kg) & 0.47 \(\pm\) 0.11 & 0.39 \(\pm\) 0.31 & 0.81 \(\pm\) 0.39 & \textless{}0.001 * & 158.1 & 0.934 \\ Hip Sagital Moment (Nm/Kg) & 6.73 \(\pm\) 0.46 & 6.48 \(\pm\) 0.34 & 6.41 \(\pm\) 0.38 & 0.197 & 1.14 & 0.16 \\ \hline \hline \end{tabular} Note: “**” means significance with \(p<0.05\).  
\end{table} 
Table 3: Detailed results of peak joint angles and moments during the cutting maneuver. the TN and the TO condition, and only a significant difference between the TI and the TO condition. The results showed that the activation of the medial gastrocnemius increased with the increasing foot external rotation angle during the initial phase of the stance (0-18%, \(p\) < 0.018). The same was true for the tibialis anterior muscle. In contrast, the activation of vastus medialis and vastus lateralis decreased with the increasing foot external rotation angle. Figure 6: Statistical parameter mapping output for semitendinosus, biceps femoris, vastus medialis, vastus lateralis, vastus medialis, rectus femoris, tibialis anterior, and soleus during the standing phase. F* is a specific threshold to distinguish between significant and non-significant regions. Figure 7D demonstrates that the activation ratios of BF/RF and H/Q are higher when the foot is in an internal rotation relative to the other two angles, and that the activation ratios of MG/TA are higher when the foot progression angles are in a neutral position compared to SOL/TA. The activation ratio of BF/VM was shown to be higher when the foot initially touched the ground in external rotation.