## 3 Results
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & & **Pre-Session** & **Post-Session** & **rANOVA** \\ \hline \multirow{2}{*}{CMJ [cm]} & SG & 34.9 \(\pm\) 4.8 & 40.9 \(\pm\) 5.7 a & \multirow{2}{*}{\(p\) = 0.038} \\  & HG & 38.2 \(\pm\) 5.4 & 40.7 \(\pm\) 5.8 & \\ \hline \multirow{2}{*}{LA [mmol/L]} & SG & 0.9 \(\pm\) 0.2 & 3.4 \(\pm\) 1.8 a,b & \multirow{2}{*}{\(p\) = 0.003} \\  & HG & 0.8 \(\pm\) 0.2 & 1.5 \(\pm\) 0.7 & \\ \hline \multirow{2}{*}{HR [bpm]} & SG & 77.9 \(\pm\) 10.0 & 150.0 \(\pm\) 15.0 & \multirow{2}{*}{\(p\) = 0.072} \\  & HG & 88.6 \(\pm\) 33.6 & 141.0 \(\pm\) 21.9 & \\ \hline \multirow{2}{*}{RPE} & SG & 1.6 \(\pm\) 0.5 & 7.7 \(\pm\) 0.7 a,b & \multirow{2}{*}{\(p\) < 0.001} \\  & HG & 1.4 \(\pm\) 0.5 & 5.2 \(\pm\) 1.2 & \\ \hline \hline \end{tabular} Values are given as mean \(\pm\) SD; a = sig. dif. to pre, b = sig. dif. SG-HG; pre-session = values were evaluated before the start of the training session, post-session = values were evaluated right after the training session was finished; SG = sand group, HG = hard court group, CMJ = countermovement jump, RPE = rate of perceived exertion on a scale of 1 to 10.  
\end{table} 
Table 2: Comparison of the SG (\(n\) = 9) and the HG (\(n\) = 9) in terms of the acute effects of a single training session. Figure 1: Illustration of absolute and percentage changes in selected speed performances of the different intervention groups pre- and post-intervention (the dashed area represents the smallest worthwhile change [SWC] for a small effect). Each color represents one participant (red-yellow color scheme with squares = SG; blue color scheme with triangles = HG; green color scheme with circles = CG). The results of the magnitude-based inferences support the results of the pairwise comparisons by showing that the likelihood that the true magnitude of the effect is beneficial in TT was highest in the SG and the HG. Based on the small effect, the changes in both the HG and SG are highly likely to be beneficial, and the same applies to the Avg Vel 1a of both the SG and HG, while the change in the CG can only be classified as likely beneficial. For Avg Vel 1b, only the change in the SG was classified as highly likely beneficial, while for Dec Dist, the change in the HG was classified as highly likely and that in the CG as likely beneficial. Statistical values regarding CoD performance are shown in Table 4. Moreover, the individual values, as well as the percentage changes, are illustrated in Figure 2 using Avg Vel 1a, Avg Vel 1b, and Dec Dist as examples. Correlation analysis revealed significant relationships between the changes in the performance of CMJ to PJST (r = 0.73), CH (r = 0.41), 5 m ST (r = \(-\)0.66), 10 m ST (r = \(-\)0.47), 20 m ST (r = \(-\)0.67), TT (r = \(-\)0.48), and Avg Vel 1a (r = 0.50). Moreover, from PSJT to CH (r = 0.63), 5 m ST (r = \(-\)0.59), 10 m ST (r = \(-\)0.52), 20 m ST (r = \(-\)0.67), TT (r = \(-\)0.48), and Avg Vel 1a (r = 0.52). We found further correlations between the changes from 5 m ST to 10 mT (r = 0.70), 20 m ST (r = 0.65), and TT (r = 0.40). In addition, between the change from 10 m ST to 20 mT (r = 0.81), as well as from 20 mT to TT (r = 0.55) and Avg Vel 1a (r = \(-\)0.51). Additionally, between TT and Avg Vel 1a (r = \(-\)0.81). The corresponding correlation matrix can be found in the appendix (Figure A3).