# Contributions of Body Segments to the Toe Velocity during Taekwondo Roundhouse Kick
## 3 Results
### Contributions of Body Segments in Impact Event  
Table 3 includes the contributions of the segments to the toe velocity in the impact event with angle-change types of footwork. Compared with the contributions in the MKF event, the contribution of thigh rotation decreased, while the contribution of the calf rotation increased significantly. In addition, the toe velocity was 15.52 m/s in the roundhouse kick without a backstep, and to reach this velocity, the contribution rate by thigh rotation was 39.8%, the contribution of calf rotation was 34.6%, the contribution of trunk rotation was 12.0%, the contribution of whole-body movement was 9.6%, the contribution of trunk movement was 8.4%, the contribution of foot rotation was 2.9%, and the contribution of others was \(-\)7.3%. In the roundhouse kick with PBS, the toe velocity was 14.87 m/s, the contribution rate of whole-body movement to reach the velocity was 8.7%, that of trunk movement was 7.8%, that of trunk rotation was 18.3%, that of thigh rotation was 36.5%, that of calf rotation was 36.8%, that of foot rotation was 2.5%, and that of others was \(-\)10.6%. In the angle-change types of footwork, the toe velocity at F0\({}^{\circ}\) was 13.66 m/s, the toe velocity at F22\({}^{\circ}\) was 13.72 m/s, the toe velocity at F45\({}^{\circ}\) was 14.06 m/s, the toe velocity at F67\({}^{\circ}\) was 15.64 m/s, and the toe velocity at F90\({}^{\circ}\) was 15.44 m/s. As the movement angle increased, the toe velocity increased. However, there was no statistically significant difference. The toe velocity by thigh rotation also increased to 3.60 m/s, 4.23 m/s, 4.68 m/s, 5.09 m/s, and 5.49 m/s with an increase in the angle, and the contribution rates also increased from 26.4% to 30.8%, 33.3%, 32.5%, and 35.5% as the backstep angle increased. Unlike the results of the kick without backstep, the contribution rate by calf rotation was higher than that of the thigh rotation, except for F90. The contribution rates of trunk rotation for PBS, F45\({}^{\circ}\), F67\({}^{\circ}\), and F90\({}^{\circ}\) were 17.8% to 18.5%, but those of F0\({}^{\circ}\) and F22\({}^{\circ}\) were 23.7% and 21.6%, respectively. The contribution rates of whole-body movement and trunk movement were similar at 7.8% to 9.9% for PBS, F45\({}^{\circ}\), F67\({}^{\circ}\), and F90\({}^{\circ}\), but they were low at 3.3% to 5.8% for F0\({}^{\circ}\) and F22\({}^{\circ}\). Table 4 includes the contributions of the segments to the toe velocity in the impact event with distance-change types of footwork. The toe velocity of PB was 16.75 m/s, and to reach this velocity, the contribution rate of whole-body movement was 8.1%, the contribution of trunk movement was 7.5%, the contribution of trunk rotation was 19.5%, the contribution of thigh rotation was 37.9%, the contribution of calf rotation was 35.4%, the contribution of foot rotation was 1.6%, and the contribution of others was \(-\)10.0%. In  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & **Whole-Body Movement** & **Trunk** & **Trunk Rotation** & **Thigh Rotation** & **Calf Rotation** & **Foot** & **Others** & **Toe Velocity** \\ \hline \multirow{2}{*}{\ \begin{tabular}{c} Kick W/O \\ Backstep \\ \end{tabular}  } & \multirow{2}{*}{\(1.48\pm 0.29\)} & \multirow{2}{*}{\(1.30\pm 0.28\)} & \multirow{2}{*}{\(1.86\pm 0.70\)} & \multirow{2}{*}{\(6.18\pm 1.94\)} & \multirow{2}{*}{\(5.38\pm 0.87\)} & \multirow{2}{*}{\(0.45\pm 0.54\)} & \multirow{2}{*}{\(-1.13\pm 1.63\)} & \multirow{2}{*}{\(15.52\pm 2.16\)} \\  & & & & & & & & \\ \multirow{2}{*}{ \begin{tabular}{c} PBS Kick \\ \end{tabular}  } & \multirow{2}{*}{\(1.29\pm 0.29\)} & \multirow{2}{*}{\(1.17\pm 0.26\)} & \multirow{2}{*}{\(2.27\pm 1.12\)} & \multirow{2}{*}{\(5.43\pm 1.36\)} & \multirow{2}{*}{\(5.47\pm 1.58\)} & \multirow{2}{*}{\(0.37\pm 0.64\)} & \multirow{2}{*}{\(-1.57\pm 1.69\)} & \multirow{2}{*}  
the roundhouse kick with PB, thigh rotation contributed the most, followed by calf rotation, trunk rotation, and whole-body movement.