# Effects of Age and Sex on the Kinematics of the Sprinting Technique in the Maximum Velocity Phase
## 3 Results
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline  & & \multicolumn{2}{c}{**Sex**} & \multicolumn{3}{c}{**Age**} & \multicolumn{3}{c}{**Interaction**} \\
**Parameter** & **F** & \(p\) & \(\eta_{p}\)2 & **F** & \(p\) & \(\eta_{p}\)2 & **F** & \(p\) & \(\eta_{p}\)2 \\ \hline Knee angle at touchdown (\(\theta\)knee\({}_{\mathrm{TD}}\), deg) & 1.476 & 0.232 & 0.038 & 1.005 & 0.323 & 0.026 & 1.261 & 0.269 & 0.033 \\ Minimum knee angle during support phase (\(\theta\)knee\({}_{\mathrm{AM}}\), deg) & 15.051 & \(<\)0.001 * & 0.295 & 2.402 & 0.130 & 0.063 & 0.675 & 0.417 & 0.018 \\ Knee flexion at the breaking phase (\(\Delta\)knee\({}_{\mathrm{AM}}\), deg) & 15.382 & \(<\)0.001 * & 0.294 & 0.019 & 0.892 & 0.001 & 1.973 & 0.168 & 0.051 \\ Knee angle at take-off (\(\theta\)knee\({}_{\mathrm{TO}}\), deg) & 0.087 & 0.770 & 0.002 & 5.051 & 0.031 * & 0.120 & 0.000 & 0.998 & 0.000 \\ Ankle horizontal velocity at touchdown (Vxankle, m/s) & 0.005 & 0.944 & 0.000 & 11.989 & 0.001 * & 0.245 & 1.537 & 0.223 & 0.040 \\ Ankle horizontal velocity at touchdown (relative to VxTD, m/s) & 9.779 & 0.003 * & 0.209 & 174.317 & \(<\)0.001 * & 0.825 & 3.163 & 0.084 & 0.079 \\ Ankle angular velocity at touchdown (wknee, rad/s) & 1.739 & 0.195 & 0.045 & 15.494 & \(<\)0.001 * & 0.295 & 0.049 & 0.825 & 0.001 \\ Ankle angle at touchdown (\(\theta\)ankle\({}_{\mathrm{TD}}\), deg) & 2.966 & 0.093 & 0.074 & 0.196 & 0.661 & 0.005 & 1.204 & 0.280 & 0.032 \\ Ankle angle at take-off (\(\theta\)ankle\({}_{\mathrm{TO}}\), deg) & 11.643 & 0.002 * & 0.239 & 0.000 & 0.999 & 0.000 & 2.626 & 0.114 & 0.066 \\ Ankle joint range of motion during support (\(\theta\)ankle\({}_{\mathrm{TO}}\), deg) & 1.233 & 0.274 & 0.032 & 0.173 & 0.680 & 0.005 & 0.070 & 0.792 & 0.002 \\ Minimum swing leg’s knee angle during support (\(\theta\)knee\({}_{\mathrm{MIN}}\), deg) & 2.086 & 0.157 & 0.053 & 8.435 & 0.006 * & 0.186 & 0.819 & 0.371 & 0.022 \\ Maximum swing leg’s knee angular velocity (\(\omega\)knee\({}_{\mathrm{S}}\), rad/s) & 0.134 & 0.716 & 0.004 & 25.982 & \(<\)0.001 * & 0.419 & 0.165 & 0.800 & 0.002 \\ Swing leg’s knee angle at take-off (\(\theta\)kne\({}_{\mathrm{S}}\), deg) & 0.010 & 0.921 & 0.000 & 0.347 & 0.560 & 0.009 & 4.861 & 0.034 * & 0.116 \\ Swing leg’s ankle angle at take-off (\(\theta\)ankles, deg) & 2.038 & 0.016 & 0.055 & 6.038 & 0.019 * & 0.147 & 4.017 & 0.053 & 0.103 \\ Swing leg’s thigh inclination at take-off (\(\phi\)thght\({}_{\mathrm{TO}}\), deg) & 0.000 & 0.990 & 0.000 & 12.972 & \(<\)0.001 * & 0.265 & 2.123 & 0.154 & 0.056 \\ Support leg inclination at touchdown (\(\theta\)ele\({}_{\mathrm{TD}}\), deg) & 1.914 & 0.175 & 0.050 & 0.864 & 0.359 & 0.023 & 0.932 & 0.341 & 0.025 \\ Support leg inclination at take-off (\(\theta\)ele\({}_{\mathrm{TO}}\), deg) & 1.567 & 0.219 & 0.042 & 2.568 & 0.118 & 0.067 & 0.251 & 0.620 & 0.007 \\ \hline \end{tabular}
*: significant sex difference; *: significant age difference; *: significant sex \(\times\) age interaction.  
\end{table} 
Table 5: Results of the statistical analysis for the linear and angular kinematics of the lower extremities’ joints and segments. Figure 3: Representative stick figures of the sprinting technique: (**a**) adult man; (**b**) prepubescent boy. The arrows indicate the differences between an adult man and a prepubescent boy: at take-off, the boy had a more extended swing leg knee joint and a less flexed ankle joint, as well as a less active arm swing of the swing leg. Before touchdown, the adult man had a more active ankle plantar flexion movement than the boy. Figure 2: Representative stick figures of the sprinting technique: (**a**) adult woman; (**b**) prepubescent girl. The arrows indicate the differences between an adult woman and a prepubescent girl: before the touchdown, the girl had an extensive rotation of the shoulder axis, and the arm was not directed in the direction of the movement. During the support phase, an excessive knee flexion was observed in the girl. During the midstance, the woman had a higher heel rise and a more flexed knee joint of the swing leg.