## 3 Results
### Results of Lower-Limb Biomechanical Characteristics
#### 3.1.3 Results of Ground Reaction Force During Landing Pre- and Post-Fatigue  
The Shapiro-Wilk test indicated that the ground reaction force data during landing followed a normal distribution.  
A paired t-test was conducted to compare ground reaction force changes during different landing phases before and after fatigue. The second peak of vertical ground reaction force (vGRF2) significantly increased post-fatigue (FDR-adjusted \(p\) = 0.0086, t = 6.722). Other GRF components did not show significant changes (\(p\) > 0.05). The detailed results are shown in Table 4 and Figure 3.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Metrics** & **Pre-Fatigue (\({}^{\circ}\))** & **Post-Fatigue (\({}^{\circ}\))** & **t** & \(p\)** \\ \hline vGRF1 (BW) & 1.79 \(\pm\) 0.31 & 1.81 \(\pm\) 0.72 & 3.712 & 0.101 \\ vGRF2 (BW) & 2.43 \(\pm\) 0.28 & 2.48 \(\pm\) 0.31 & 6.722 & 0.006 \\ aGRF (BW) & 0.34 \(\pm\) 0.17 & 0.35 \(\pm\) 0.11 & 1.092 & 0.114 \\ pGRF (BW) & 0.58 \(\pm\) 0.29 & 0.55 \(\pm\) 0.14 & 3.714 & 0.077 \\ mGRF (BW) & 0.12 \(\pm\) 0.03 & 0.13 \(\pm\) 0.09 & 0.628 & 0.697 \\ IGRF (BW) & 0.35 \(\pm\) 0.15 & 0.29 \(\pm\) 0.13 & 3.219 & 0.081 \\ \hline \hline \end{tabular}  
* Notes: vGRF1: first peak of vertical ground reaction force; vGRF2: second peak of vertical ground reaction force; aGRF: anterior ground reaction force; pGRF: posterior ground reaction force; mGRF: medial ground reaction force; IGRF: lateral ground reaction force.  
\end{table}
Table 4: Results of ground reaction force during landing pre- and post-fatigue.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Joint** & **Phase** & **Pre-Fatigue (\({}^{\circ}\))** & **Post-Fatigue (\({}^{\circ}\))** & **t** & \(p\)** \\ \hline \multirow{4}{*}{Hip} & IC (\({}^{\circ}\)) & 125.23 \(\pm\) 3.26 & 119.59 \(\pm\) 4.57 & 2.452 & 0.021 \\  & TM (\({}^{\circ}\)) & 144.67 \(\pm\) 2.33 & 150.51 \(\pm\) 1.52 & 1.371 & 0.074 \\  & ROM (\({}^{\circ}\)) & 36.39 \(\pm\) 3.88 & 40.19 \(\pm\) 3.42 & 3.164 & 0.001 \\  & IC (\({}^{\circ}\)) & 167.31 \(\pm\) 5.26 & 159.29 \(\pm\) 4.32 & 3.377 & 0.013 \\ Knee & TM (\({}^{\circ}\)) & 156.67 \(\pm\) 6.13 & 152.75 \(\pm\) 2.58 & 5.426 & 0.005 \\  & ROM (\({}^{\circ}\)) & 50.21 \(\pm\) 5.24 & 55.79 \(\pm\) 4.65 & 6.213 & 0.001 \\  & IC (\({}^{\circ}\)) & 95.11 \(\pm\) 8.12 & 97.59 \(\pm\) 1.29 & 2.274 & 0.113 \\ Ankle & TM (\({}^{\circ}\)) & 112.56 \(\pm\) 10.14 & 116.31 \(\pm\) 12.81 & 1.022 & 0.251 \\  & ROM (\({}^{\circ}\)) & 29.61 \(\pm\) 7.14 & 31.21 \(\pm\) 3.51 & 2.216 & 0.003 \\ \hline \hline \end{tabular}  
* Notes: IC: initial contact; TM: takeoff moment (takeoff instance); ROM: range of motion.  
\end{table}
Table 2: Results of lower-limb joint angles during landing before and after fatigue.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Joint** & **Pre-Fatigue (\({}^{\circ}\))** & **Post-Fatigue (\({}^{\circ}\))** & **t** & \(p\)** \\ \hline Hip (N\(\cdot\)m/kg) & 2.71 \(\pm\) 1.27 & 2.91 \(\pm\) 0.78 & 1.542 & 0.057 \\ Knee (N\(\cdot\)m/kg) & 2.77 \(\pm\) 2.27 & 3.58 \(\pm\) 1.79 & 3.121 & 0.004 \\ Ankle (N\(\cdot\)m/kg) & 3.66 \(\pm\) 0.42 & 3.21 \(\pm\) 0.69 & 0.981 & 0.623 \\ \hline \hline \end{tabular}  
* 3.1.3 Results of Ground Reaction Force During Landing Pre- and Post-Fatigue
* The Shapiro-Wilk test indicated that the ground reaction force data during landing followed a normal distribution.
* A paired t-test was conducted to compare ground reaction force changes during different landing phases before and after fatigue. The second peak of vertical ground reaction force (vGRF2) significantly increased post-fatigue (FDR-adjusted \(p\) = 0.0086, t = 6.722). Other GRF components did not show significant changes (\(p\) > 0.05). The detailed results are shown in Table 3 and Figure 3.  
\end{table}
Table 3: Results of lower-limb joint moments during landing before and after fatigue.