## 3 Results
### Secondary Outcomes  
Regarding knee proprioception, the time factor (\(p\) = 0.350), condition factor (\(p\) = 0.472), and time factor \(\times\) condition factor (\(p\) = 0.551) were not significant (Table 1). Furthermore, compared with EB intervention, FB intervention resulted in no substantial difference either immediately (\(p\) = 0.53) and 20 min later (\(p\) = 0.4).  
Regarding quadriceps muscle force output, the time factor (\(p\)! 0.001) exhibited a significant difference, but the condition factor (\(p\) = 0.731) and the time factor \(\times\) condition factor (\(p\) = 0.551) were not significant. In the post hoc test, participants demonstrated significant improvement after FB intervention (immediately: \(p\) = 0.007, ES = 1.94; 20 min  
\begin{table}
\begin{tabular}{c c c} \hline  & **Post Immediately** & **20 min Later** \\  & **AFB-\(\Delta\)EB** & **\(\Delta\)FB-\(\Delta\)EB** \\  & **(Effect Size)** & **(Effect Size)** \\ \hline Hamstring flexibility (degree) & 10.06 \(\pm\) 5.3 & 9.18 \(\pm\) 8.81 \\  & (2.09) & (1.58) \\ \hline Quadriceps flexibility (degree) & 2.87 \(\pm\) 5.31 & 2.83 \(\pm\) 4.22 \\  & (0.76) & (0.84) \\ \hline Joint proprioception (degree) & \(-\)0.96 \(\pm\) 4.06 & 0.17 \(\pm\) 5.52 \\  & (\(-\)0.24) & (0.04) \\ \hline Quadriceps Muscle Force Output & 0.07 \(\pm\) 0.53 & 0.07 \(\pm\) 0.36 \\ (N-m/Kg) & Effect size & (0.17) & (0.21) \\ \hline Hamstrings Muscle Force Output & 0.02 \(\pm\) 0.35 & 0.15 \(\pm\) 0.34 \\  & (0.08) & (0.65) \\ \hline Y-balance test & 0.02 \(\pm\) 0.04 & 0.03 \(\pm\) 0.05 \\  & (0.85) & (0.66) \\ \hline \end{tabular} Data are reported as raw difference in values (mean \(\pm\) SD) with effect size for comparison between the FB and EB intervention. Hamstring flexibility was measured using the popitleus test, which measures poplitleal angle (degree) between the thigh and leg. Quadriceps flexibility was measured using Ely’s test, which measures the knee flexion angle (degree) between the thigh and leg.  
\end{table}
Table 2: Comparison of postintervention with preintervention values.  
later: \(p<0.001\), ES = 1.8) and EB intervention (immediately: \(p=0.007\), ES = 0.36; 20 min later: \(p<0.001\), ES = 0.25) relative to their baseline data (Table 1).  
Regarding hamstring muscle force output, the time factor (\(p=0.204\)) did not exhibit a significant difference, but the condition factor (\(p<0.001\)) and time factor \(\times\) condition factor (\(p=0.033\)) were significant. In the post hoc test, participants exhibited a significant decrease after FB intervention immediately (\(p<0.001\), ES = 1.75) but not after 20 min (\(p=1\), ES = 0). However, significant decreases were indicated after EB intervention (immediately: \(p<0.001\), ES = 1.83; 20 min later: \(p<0.001\), ES = 0.32; Table 1). Furthermore, the difference between conditions was associated with a medium-effect size in favor of the FB intervention 20 min later (ES = 0.65; Table 2).  
Regarding the YBT, the condition factor (\(p=0.078\)) was nonsignificant. However, the time factor (\(p<0.001\)) and time factor \(\times\) condition factor (\(p<0.001\)) were significant. In the post hoc test, participants exhibited significant improvement after FB intervention (immediately: \(p<0.001\); 20 min later: \(p<0.001\)) but not after EB intervention (immediately: \(p=0.25\); 20 min later: \(p=0.208\); Table 1). Furthermore, compared with EB intervention, FB intervention resulted in significant improvement both immediately (\(p=0.016\)) and 20 min later (\(p=0.004\)). The difference between conditions was associated with a medium-to-large effect size in favor of FB intervention immediately (ES = 0.85) and 20 min later (ES = 0.66; Table 2).