## 4 Discussion  
The current study hypothesized that, compared to the double-leg landing, single-leg landing would have a smaller hip and knee flexion angles at the time of initial foot contact with the ground, (2) have lower hip and knee flexion angular velocities at the time of initial foot contact with the ground, (3) have a greater GRF during landing, (4) have a greater knee joint reaction force during landing, and (5) have a greater knee flexion moment during landing. The present research has provided support through the obtained evidence \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**LFL**} & \multicolumn{2}{c}{**SSL**} & \multicolumn{2}{c}{**URL**} \\ \hline  & **Double Leg** & **Single Leg** & **Double Leg** & **Single Leg** & **Double Leg** & **Single Leg** \\ \hline Hip & \(-49\pm 12.8\) & \(-51.7\pm 22.3\) & \(-43.3\pm 13.7\) & *\(-63.9\pm 23.1\) & *\(-44.2\pm 13.1\) & * \(-59.2\pm 21.9\) \\ \hline Knee & \(-44.8\pm 13.6\) & \(-61.2\pm 22\) & \(-44.9\pm 12.7\) & \(-64.9\pm 29.5\) & \(-46.7\pm 16.6\) & * \(-59.2\pm 26.1\) \\ \hline Ankle & * \(46\pm 8\) & * \(48\pm 13\) & \(45\pm 11\) & \(40\pm 6\) & \(58\pm 30\) & \(66\pm 34\) \\ \hline \hline \end{tabular}  
* Significant main effect at a level of less than 0.05. Negative directions indicate hip and knee flexion, positive directions indicates ankle dorsiflexion. LFL leaning forward landing; SSL self-selected landing, URL upright landing.  
\end{table} 
Table 2: Descriptive statistics and results of 2-way repeated measure ANOVAs (Mean \(\pm\) SD) comparisons of sagittal plan trunk angles (LFL, SSL and URL) and hip, knee and ankle flexion angles during double/single-leg landing. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**LFL**} & \multicolumn{2}{c}{**SSL**} & \multicolumn{2}{c}{**URL**} \\ \hline  & **Double Leg** & **Single Leg** & **Double Leg** & **Single Leg** & **Double Leg** & **Single Leg** \\ \hline Hip & \(-69.9\pm 27.3\) & \(-77.1\pm 27.6\) & \(-67.8\pm 22.6\) & *\(-81.9\pm 33.8\) & \(-684.21\) & * \(-87.6\pm 50.7\) \\ \hline Knee & \(-36\pm 11.9\) & \(-39.7\pm 19.2\) & \(-36.1\pm 12.8\) & \(-43.7\pm 27.7\) & * \(-34.3\pm 10.7\) & * \(-45.1\pm 30.6\) \\ \hline Ankle & \(39.7\pm 6.2\) & \(41.2\pm 6.9\) & \(37.8\pm 6\) & \(38.4\pm 4.7\) & * \(23\pm 18.6\) & * \(16.7\pm 21.2\) \\ \hline \hline \end{tabular}  
* Significant main effect at a level of less than 0.05. Negative directions indicate hip and knee flexion, positive directions indicates ankle dorsiflexion. LFL leaning forward landing; SSL self-selected landing; URL upright landing.  
\end{table} 
Table 3: Descriptive statistics and results of 2-way repeated measures ANOVA (Mean \(\pm\) SD) comparisons of sagittal plan trunk angles (LFL, SSL and URL) and hip, knee and ankle flexion angles during double/single-leg landing. indicating significant levels for the torque angle during dorsiflexion, hip flexion and knee flexion (\(p\leq 0.05\)). The contention that the shock absorption of the ankle joint angle is lessened in URL was further supported in our study (\(16.7\pm 21.2\)). This observation indicates that LFL allowed the participants sufficient time to produce the peak ankle plantar flexor moment before the peak GRF occurred, increasing the proportion of GRF absorption by the ankle. Corresponding to requiring less dorsiflexion during landing (more plantar flexion), subjects showed significant results for the ankle (Table 2). Conversely, during URL, the peak GRF occurred before the peak ankle plantar flexor moment. Collectively, these results support previous suggestions that shock-attenuating capacity is higher in LFL than in URL [15]. Our results showed that the greatest peak knee extensor moment occurred during single-leg landing with the URL trunk position and the smallest peak knee extensor moment occurred during single-leg landing with the LFL trunk position. The hip extensor moments at the time of peak knee extensor moment were greater for URL than for LFL.