## 3 Results  
Changes in the Lysholm score and IKDC subjective score via rehabilitation intervention in each group are shown in Table 2. Except for the main impact of time, there was no significant interaction in the Lysholm score (\(p<0.001\)\(\eta^{2}=0.623\)) and the subjective IKDC score (\(p<0.001\), \(\eta^{2}=0.533\)). Post-hoc analysis found a significant increase of the Lysholm score in GRE (\(p<0.01\)) and BFR (\(p<0.001\)) via the rehabilitation exercise program after ACL reconstruction. Additionally, a significant increase was found for the IKDC subjective score in GRE (\(p<0.05\)) and BFR (\(p<0.001\)).  
The muscle activities of VMO, VLO and RF during constant velocity contraction through rehabilitation intervention in each group are shown in Table 3. There was a significant interaction in the muscle activity of VMO (\(p=0.009\), \(\eta^{2}=0.269\)) during isokinetic contraction. In addition, there was a significant main effect over time in the muscle activity of VMO (\(p=0.003\), \(\eta^{2}=0.334\)) and RF (\(p=0.019\), \(\eta^{2}=0.224\)) during isometric contraction. Post-hoc analysis found that a significant increase of VMO (\(p<0.001\)) RF (\(p<0.05\)) during isometric contraction in BFR.  
Table 4 shows the isokinetic muscle function through rehabilitation intervention in each group. The main effects of interaction and time appeared on hamstring peak torque (\(p<0.006\), \(\eta^{2}<0.301\)) and total work (\(p<0.008\), \(\eta^{2}=0.280\)). In the quadriceps femoris, the main effects of time appeared on peak torque (\(p=0.005\), \(\eta^{2}=0.311\)) and total work (\(p=0.015\), \(\eta^{2}=0.240\)). Post-hoc analysis found that a significant increase of peak torque (\(p<0.01\)) and total work (\(p<0.05\)) in BFR.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Variables**} & \multirow{2}{*}{**Group**} & \multicolumn{2}{c}{**Intervention**} & \multicolumn{2}{c}{**Mean Change**} & \multicolumn{2}{c}{\(p\) (\(\eta^{2}\)) Value**} \\ \cline{3-8}  & & **Before** & **After** & **95\% CI** & **Group** & **Time** & **Interaction** \\ \hline Lysholm score & GRE & 69.17 \(\pm\) 11.94 & 83.08 \(\pm\) 6.32 & 13.92 [4.92, 22.92] ** & 0.835 & 0.000 & 0.158 \\ (points) & BFR & 63.67 \(\pm\) 21.82 & 86.50 \(\pm\) 12.27 & 22.83 [12.87, 32.80] ** & 0.002 & (0.623) \(\dagger\) & (0.089) \\ \hline IKDC score & GRE & 62.39 \(\pm\) 14.11 & 73.25 \(\pm\) 9.94 & 10.86 [0.27, 21.45] * & 0.971 & 0.000 & 0.290 \\ (points) & BFR & 59.55 \(\pm\) 12.04 & 76.42 \(\pm\) 14.32 & 16.87 [10.83, 22.91] ** & 0.000 & (0.533) \(\dagger\) & (0.051) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Changes in the Lysholm score and IKDC subjective score via rehabilitation intervention in each group.  
Table 5 showed a significant interaction for Y-balance anterior (\(p\) = 0.046, \(\eta^{2}\) = 0.170) and posterior lateral (\(p\) < 0.048, \(\eta^{2}\) = 0.167). There was also a substantial main effect of time for Y-balanced posteromedial (\(p\) < 0.001, \(\eta^{2}\) = 0.583). Post-hoc analysis found that Y-balance anterior significantly increased via intervention in BFR (\(p\) < 0.01) and Y-balance posterior medial (GRE, \(p\) < 0.05; BFR, \(p\) < 0.001) and Y-balance posterior lateral (GRE, \(p\) < 0.05; BFR, \(p\) < 0.05) significantly increased via intervention in all groups.