# Effects of Age and Sex on the Kinematics of the Sprinting Technique in the Maximum Velocity Phase
## 3 Results  
The results regarding the RV are presented in Figure 1. A significant effect of age (\(F_{(1,41)}\) = 281.38, _p_! 0.001, \(\eta_{p}\)\({}^{2}\) = 0.89), a significant sex effect (\(F_{(1,41)}\) = 7.93, _p_! 0.008, \(\eta_{p}\)\({}^{2}\) = 0.19), and an interaction of age \(\times\) sex (\(F_{(1,41)}\) = 5.64, _p_! 0.001, \(\eta_{p}\)\({}^{2}\) = 0.14) were found. Table 2 depicts the results for the step parameters and the BCM kinematics, whereas Table 3 presents the results of the statistical analysis for the above-mentioned variables. Results indicated a significant (_p_! 0.05) main effect of sex in the step temporal parameters (SF and contact time); however, these parameters were significantly (_p_! 0.05) different between AM and AF but not between PPB and PPG. This was also the case for the other parameters that were found to be statistically different between sexes in adulthood but were not different in prepubescence (horizontal BCM take-off velocity, angle of projection, touchdown distance). Also, a significant (_p_! 0.05) main effect of age was observed for the step parameters, the temporal structure of the step and the BCM kinetics (horizontal and vertical take-off velocity, its lowering during the support phase, and its distance from the point of support at the take-off). Finally, a significant (_p_! 0.05) interaction of age \(\times\) sex was revealed for the horizontal BCM take-off velocity and the angle of projection. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Parameter** & **AM (_n = 14_)** & **AF (_n = 8_)** & **PPB (_n = 10_)** & **PPG (_n = 10_)** \\ \hline Knee angle at touchdown (@kneeTD, deg) & \(148.9\pm 7.6\) & \(148.7\pm 6.7\) & \(149.0\pm 5.1\) & \(144.0\pm 6.9\) \\ \hline Minimum knee angle during support phase (@kneeAM, deg) & \(145.4\pm 7.1\) & \(139.1\pm 5.5\) & \(143.9\pm 5.0\) & \(134.3\pm 6.7\) \\ Knee flexion at the breaking phase (\(\Delta\)kneeAM, deg) & \(-3.5\pm 2.0\) & \(-9.6\pm 6.2\) * & \(-5.2\pm 2.4\) & \(-8.1\pm 3.8\) \\ Knee angle at take-off (@kneeTO, deg) & \(153.7\pm 0.6\) & \(154.2\pm 5.2\) & \(157.5\pm 5.6\) & \(158.0\pm 5.5\) \\ Ankle horizontal velocity at touchdown (Vxankle, m/s) & \(1.95\pm 0.46\) & \(1.66\pm 0.40\) & \(2.45\pm 0.40\) & \(2.71\pm 1.20\) * \\ Ankle horizontal velocity at touchdown (relative to \(-7.40\pm 0.74\) & \(-7.40\pm 0.74\) & \(-6.18\pm 0.43\) & \(-3.69\pm 0.60\) * & \(-3.35\pm 1.08\) * \\ Ankle angular velocity at touchdown (@knee, rad/sec) & \(-5.4\pm 1.4\) & \(-6.1\pm 2.5\) * & \(-2.5\pm 2.8\)* & \(-3.5\pm 2.1\) * \\ Ankle angle at touchdown (@ankleTD, deg) & \(103.6\pm 5.4\) & \(109.1\pm 6.0\) * & \(104.9\pm 4.4\) & \(106.1\pm 7.8\) \\ Ankle angle at take-off (@ankleTO, deg) & \(123.2\pm 4.3\) & \(131.4\pm 4.1\) * & \(125.9\pm 6.4\) & \(128.8\pm 5.2\) \\ Ankle joint range of motion during support (@ankleTO, deg) & \(19.6\pm 5.3\) & \(22.3\pm 6.1\) & \(21.0\pm 8.0\) & \(22.7\pm 6.1\) \\ Minimum swing leg’s knee angle during support & \(35.5\pm 5.9\) & \(33.9\pm 5.1\) & \(46.8\pm 14.6\) & \(39.9\pm 8.2\) \\ (@kneeMIN, deg) & & \(16.8\pm 2.5\) & \(16.7\pm 2.0\) & \(13.2\pm 1.5\) & \(12.8\pm 2.5\) \\ Maximum swing leg’s knee angular velocity (@knees, deg) & \(69.0\pm 7.4\) & \(76.5\pm 12.2\) * & \(78.1\pm 14.4\) & \(71.3\pm 5.9\) \\ Swing leg’s ankle angle at take-off (@ankleS, deg) & \(109.7\pm 6.7\) & \(118.7\pm 10.8\) * & \(108.5\pm 7.5\) & \(107.0\pm 7.8\) \\ Swing leg’s thigh inclination at take-off (@\(\mathrm{@ughlin_{TO}}\), deg) & \(-15.1\pm 7.2\) & \(-18.5\pm 7.0\) * & \(-26.7\pm 5.6\) & \(-23.4\pm 7.7\) \\ Support leg inclination at touchdown (@elegTO, deg) & \(78.0\pm 4.0\) & \(75.7\pm 4.9\) & \(75.2\pm 3.9\) & \(74.2\pm 3.7\) \\ Support leg inclination at take-off (@elegTO, deg) & \(51.9\pm 3.6\) & \(54.7\pm 2.3\) & \(51.9\pm 4.0\) & \(52.4\pm 3.8\) \\ \hline \end{tabular}  
* AM: adult men; AF: adult women; PPB: prepubertal boys; PPG: prepubertal girls; *: significant sex difference; *: significant age difference.  
\end{table}