# Contributions of Body Segments to the Toe Velocity during Taekwondo Roundhouse Kick
## 3 Results  
### Contributions of Body Segments in Minimum Knee Flexion (MKF) Event  
Table 1 contains the contributions of the segments to the toe velocity in the minimum knee flexion (MKF) event with angle-change types of footwork. In all types of kicks, thigh rotation showed the most significant contribution with a rate of 51.0 to 64.4%, and trunk rotation had the second highest contribution rate (16.7 to 29.9%). Whole-body movement (10.1 to 13.4%) was ranked third, and the contribution rate of trunk movement was 4.6 to 7.8%, indicating a significant difference between types of footwork.  
During the kick without a backstep, the toe velocity was 10.45 m/s in the MKF event, the contribution rate of thigh rotation was 53.9%, the contribution rate of trunk rotation was 24.3%, the contribution rate of whole-body movement was 12.4%, the contribution rate of trunk movement was 6.5%, the contribution rate of calf rotation was 2.5%, the contribution rate foot rotation was 0.2%, and the contribution rate of others was 0.3% The contribution of thigh rotation was the highest, followed by trunk rotation and whole-body movement.  
The results from the types of one-foot backstep footwork showed that the toe velocity at F0\({}^{\circ}\) was 8.05 m/s, that at F22\({}^{\circ}\) was 9.05 m/s, that at F45\({}^{\circ}\) was 9.47 m/s, that at F67\({}^{\circ}\) was 9.85 m/s, and that at F90\({}^{\circ}\) was 10.87 m/s. The velocity of the toe increased with an increase in the angle, and there was a statistically significant difference.  
There was a statistically significant difference in toe velocity, and the difference in toe velocity was a result of increasing the contribution of whole-body movement, trunk movement, and trunk rotation. The toe velocity influenced by thigh rotation also increased with an increase in the movement angle, but it did not reach the increase rate of the toe velocity, so the contribution rate to the toe velocity decreased as the movement angle increased. The toe velocity influenced by trunk rotation also increased to 1.46 m/s, 1.51 m/s, 2.05 m/s, 2.26 m/s, and 2.51 m/s as the angle increased. The contribution rate was 18.1% in F0 and 16.7% in F22, in which the toe velocity was low, and it increased to 21.6%, 22.9%, and 23.1% as the angle increased.  
Table 2 contains the contributions of the segments to the toe velocity in the minimum knee flexion (MKF) event with distance-change types of footwork. The toe velocity was 9.83 m/s for PB, 10.28 m/s for LB, 9.96 m/s for SB, 10.10 m/s for CBS, and 10.49 m/s for DSB. There was no statistical difference in the toe velocity across the distance-changes types of footwork. However, there was a statistically significant difference between SB and CBS, between SB and DSB in whole-body movement, and between SB and DSB in trunk movement. Similar to the results of the type of angle change, it was found that the contribution was greatest for thigh rotation, followed by trunk rotation, and whole-body movement.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline  & **Whole-Body** & **Trunk** & **Trunk** & **Thigh** & **Calf** & **Foot** & **Others** & **Toe** \\  & **Movement** & **Movement** & **Rotation** & **Rotation** & **Rotation** & **Rotation** & **Rotation** & **Objective** \\ \hline Kick w/o & 1.30 \(\pm\) 0.20 & 0.68 \(\pm\) 0.21 & 2.54 \(\pm\) 1.20 & 5.63 \(\pm\) 0.76 & 0.26 \(\pm\) 1.32 & 0.02 \(\pm\) 0.31 & 0.03 \(\pm\) 1.24 & 10.45 \(\pm\) 1.69 \\ Backstep & 12.4\% & 6.5\% & 24.3\% & 53.9\% & 2.5\% & 0.2\% & 0.3\% & 100.0\% \\ \hline PBS Kick [22] & 12.8 \(\pm\) 0.15 & 0.67 \(\pm\) 0.23 & 2.97 \(\pm\) 0.95 & 5.43 \(\pm\) 0.47 & \(-\)0.22 \(\pm\) 1.08 & \(-\)0.04 \(\pm\) 0.37 & \(-\)0.19 \(\pm\) 1.10 & 9.90 \(\pm\) 1