## 4 Discussion  
The main aim of the current study was (1) to assess the effect of including the lateral-step or sidestep exercise with elastic bands on multidirectional speed abilities (linear, COD, and curve sprinting) and navicular drop, and (2) to know the impact of navicular drop \begin{table}
\begin{tabular}{c c c c c c c} \hline  & \multicolumn{2}{c}{**Pre-**} & \multicolumn{2}{c}{**Mid-**} & \multicolumn{2}{c}{**Post-**} \\ \hline  & **A** & **B** & **A** & **B** & **A** & **B** \\ \hline NDR (cm) & 0.08 (0.02) & 0.09 (0.02) & 0.04 (0.03) \({}^{\star}\) & 0.10 (0.04) & 0.04 (0.04) \({}^{\star}\) & 0.10 (0.05) \\ NDL (cm) & 0.07 (0.02) & 0.07 (0.03) & 0.05 (0.03) \({}^{\star}\) & 0.07 (0.04) & 0.05 (0.03) & 0.06 (0.05) \\
10 m (s) & 1.86 (0.09) & 1.86 (0.11) & 1.77 (0.09) \({}^{\star}\) & 1.84 (0.11) & 1.77 (0.09) \({}^{\star}\) & 1.81 (0.09) \({}^{\star}\) \\ CSR (s) & 2.66 (0.19) & 2.54 (0.12) & 2.61 (0.17) \({}^{\star}\) & 2.52 (0.14) & 2.59 (0.17) \({}^{\star}\) & 2.47 (0.11) \({}^{\star}\)\({}^{\star}\)\({}^{\star}\) \\ CSL (s) & 2.83 (0.18) & 2.58 (0.11) & 2.78 (0.17) \({}^{\star}\) & 2.56 (0.11) & 2.77 (0.19) \({}^{\star}\) & 2.52 (0.09) \({}^{\star}\)\({}^{\star}\) \\ V-cut (s) & 7.44 (0.43) & 6.98 (0.44) & 7.29 (0.39) \({}^{\star}\) & 6.94 (0.41) & 7.29 (0.35) \({}^{\star}\) & 6.81 (0.39) \({}^{\star}\)\({}^{\star}\)\({}^{\star}\) \\ \hline \end{tabular} Note: NDR: navicular drop with right leg: NDL: navicular drop with left leg: CSR: curve sprinting to the right; CSL: curve sprinting to the left; V-cut: 25 m sprint with four changes of direction of 45\({}^{\circ}\) and 5 m each. \({}^{\star}p<0.05\) compared to pre-. \(\#\)\(p<0.05\) compared to mid-. \({}^{\star}p<0.05\) vs. group A using the mid-intervention value as a covariate.  
\end{table} 
Table 1: Within- and between-group comparison after the 3-week lateral step with elastic bands intervention. Values represent the mean (SD). changes on multidirectional sprinting changes in young male football players. The main findings were (1) the sidestep exercise with elastic bands significantly improved the ability to sprint multidirectionally in only three weeks of training, and (2) there was a trend in the impact of multidirectional sprinting performance through those changes reported in the navicular drop test. One of the most important findings was the curve sprinting and COD speed (i.e., V-cut test) improvements (ES = 0.28 to 0.40) through a short elastic band intervention based on the lateral-step exercise. Previous studies [4,18,21,22,23,24] have found COD and linear sprinting improvements (ES = \(-\)0.07 to 1.79) after using different training methods. Firstly, the device overloading the movement seems to be the most important variable in developing multidirectional adaptations in football players. In this regard, those who have used an inertial rotational device [4,24] have achieved greater improvements (ES = 1.22 to 1.79) in comparison to the rest of the studies. Some authors [24,25] argue that the COD improvement might be closely related to the musculoskeletal system's capacity to tolerate eccentric loads in the braking phase before COD. Secondly, the force vector, or movement plane, is another important variable supporting the current adaptations. Specifically, those studies where football players have applied force in the specific force vector [4,24] have reported greater improvements compared to those who did not, as occurred in the current study. If we focus on the elastic bands used, the only study where the specific force vector is stressed (i.e., medial-lateral) is the current study. Other studies [18,21] have added elastic bands to traditional exercises like squats and deadlifts, focusing on the vertical axis, showing substantial [21] (ES: 0.81 to 0.82) or no improvements [18].