# Effects of Differential Jump Training on Balance Performance in Female Volleyball Players
## 3 Results  
One ankle sprain occurred during the control phase, with no effect on data collection and presentation. One participant missed the first measurement; removal from analyses was not required thanks to the statistical approach. The performances at the three measurement sessions, covariance specifications of the final models, and the effects of measurements are presented in Table 1. \begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Control Phase**} & \multicolumn{4}{c}{**Intervention Phase**} \\ \cline{2-10}  & \multicolumn{2}{c}{**Control**} & \multicolumn{2}{c}{**Post-Control**} & \multicolumn{2}{c}{**Pre-Intervention**} & \multicolumn{4}{c}{**Post-Intervention**} \\ \cline{2-10}  & \multicolumn{2}{c}{**Mean \(\pm\) SD**} & \multicolumn{2}{c}{**Mean \(\pm\) SD**} & \multicolumn{2}{c}{**Mean \(\pm\) SD**} & \multicolumn{2}{c}{**Mean \(\pm\) SD**} & \multicolumn{2}{c}{**F**} & \multicolumn{2}{c}{_df_} & \multicolumn{1}{c}{_p_} \\ \cline{2-10}  & \multicolumn{2}{c}{**95\% CI**} & \multicolumn{2}{c}{**SE**} & \multicolumn{2}{c}{**95\% CI**} & \multicolumn{2}{c}{**SE**} & \multicolumn{2}{c}{**95\% CI**} & \multicolumn{2}{c}{} & \\ \hline WB performance [\%] & 27.02 & + & 13.18 & (-5.20) & 19.60 & \(\pm\) & 11.31 & 42.87 & 59.49 & \(\pm\) & 16.16 & 88.03 & 2, 14.17 & \(<\)0.001 \\  & 18.17 & - & 35.87 & (2.71) & 12.00 & - & 27.19 & 3.05 & 48.64 & \(\pm\) & 70.35 & 88.03 & 2, 14.17 & \(<\)0.001 \\ Sway area [cm\({}^{2}\)]§ & 8.03 & \(\pm\) & 3.28 & 6.35 & 10.91 & \(\pm\) & 3.42 & \(-\)6.63 & 8.02 & \(\pm\) & 2.89 & 23.41 & 2, 2.90 & \(<\)0.05 \\  & 5.82 & - & 10.23 & 1.01 & 8.61 & \(-\) & 13.21 & 1.31 & 6.01 & \(-\) & 9.96 & 23.41 & 2, 2.90 & \(<\)0.05 \\ AP sway [mm] \(\uparrow\) & 7.04 & + & 1.61 & (1.03) & 9.18 & \(\pm\) & 1.93 & \(-\)0.79 & 7.09 & \(\pm\) & 1.47 & 1.53 & 2, 33.33 & 0.34 \\  & 5.96 & - & 8.12 & (0.66) & 7.88 & \(-\) & 10.47 & (0.81) & 6.10 & \(-\) & 8.08 & 1.53 & 2, 33.33 & 0.34 \\ ML sway [mm] \(\uparrow\) & 6.02 & \(\pm\) & 1.23 & 0.98 & 6.34 & \(\pm\) & 0.98 & \(-\)12.44 & 5.82 & \(\pm\) & 1.12 & 8.41 & 2, 9.58 & \(<\)0.01 \\  & 5.19 & - & 6.85 & 0.29 & 5.69 & \(-\) & 7.00 & 0.30 & 5.06 & \(-\) & 6.58 & & \\ CoP velocity [mm\(\sim\)\({}^{1}\)]§ & 68.54 & + & 6.86 & (3.51) & 67.88 & \(\pm\) & 8.12 & \(-\)5.85 & 64.08 & \(\pm\) & 7.88 & & \\  & 63.93 & - & 73.15 & (2.18) & 62.42 & \(-\) & 73.34 & 2.11 & 58.78 & \(-\) & 69.37 & 4.77 & 2, 14.47 & \(<\)0.05 \\ Asymmetry [\%]§ & 23.64 & + & 17.33 & (6.38) & 32.69 & + & 23.30 & \(-\)25.89 & 10.15 & \(\pm\) & 8.26 & \\  & 11.24 & - & 36.03 & (6.76) & 16.02 & \(-\) & 49.36 & 6.23 & 4.24 & \(-\) & 16.07 & 9.62 & 2, 52.33 & \(<\)0.001 \\ \hline \hline \end{tabular} Note: Control, Post-Control, Pre-Intervention, and Post-Intervention denote measurement timings; WB, wobble board; AP, anterior–posterior; ML, mediolateral; CoP, center of pressure; _df_, degrees of freedom for the numerator and denominator, separated by a comma; \(\beta\) is converted so that negative values indicate decreased values from the previous to the subsequent measurement; and SB relate to two adjacent measurements and are in parentheses if the effect was not significant (\(p>0.05\)); Covariance structure specification: \(\uparrow\), antedependence first order; §, unstructured; \(\downarrow\), factor analytic first order; \(V\), heterogeneous autoregressive first order.  
\end{table} 
Table 1: Means \(\pm\) standard deviations (SDs), 95% confidence intervals (CIs), \(F\)-statistics for the main effect of measurements, estimates (\(\beta\)), and standard error (SE) for effects between single measurements. The best model with measurement as the only predictor for WB performance included a fixed and a random intercept, a fixed slope for measurement, and an error. It detected a main effect for measurements (\(F(2,58.24)=173.83\), \(p<0.001\)), decrease from control to pre-intervention (\(\beta=-8.86\), SE = 2.36, \(p<0.001\)), and increase from pre- to post-intervention (\(\beta=40.69\), SE = 2.29, \(p<0.001\)).