## 4 Discussion  
This study aimed to assess the effects of a 10-week Aqua Vest-based unstable load training program on lower extremity kinematics and pain reduction in middle-aged women  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & \multicolumn{2}{c}{**Stair Ascent**} & \multicolumn{2}{c}{**Stair Descent**} \\ \hline
**Angle Variables (\({}^{\circ}\))** & & **Training** & **EG** & **CG** & **EG** & **CG** \\ \hline \multirow{2}{*}{ \begin{tabular}{c} Ankle Dorsi–plantar flexion ROM \\ \end{tabular}  } & \multirow{2}{*}{Non-dominant} & pre & 39.46 \(\pm\) 5.96 & 44.29 \(\pm\) 6.86 & 28.71 \(\pm\) 6.26 & 27.83 \(\pm\) 9.66 \\ \cline{3-6}  & & post & 42.77 \(\pm\) 4.33 \({}^{\star}\) & 45.38 \(\pm\) 7.23 & 34.40 \(\pm\) 10.36 \({}^{\star}\) & 29.79 \(\pm\) 8.49 \\ \cline{3-6}  & & pre & 39.15 \(\pm\) 6.83 & 43.53 \(\pm\) 6.22 & 29.89 \(\pm\) 4.35 & 28.52 \(\pm\) 7.95 \\ \cline{3-6}  & & post & 41.72 \(\pm\) 5.59 & 45.13 \(\pm\) 5.92 & 33.81 \(\pm\) 11.34 & 31.28 \(\pm\) 8.64 \\ \hline \multirow{2}{*}{ \begin{tabular}{c} Ankle Inversion–eversion ROM \\ \end{tabular}  } & \multirow{2}{*}{Non-dominant} & pre & 4.65 \(\pm\) 1.81 & 3.60 \(\pm\) 1.68 & 2.46 \(\pm\) 1.08 & 2.73 \(\pm\) 1.43 \\ \cline{3-6}  & & post & 4.15 \(\pm\) 1.99 & 3.12 \(\pm\) 1.61 & 2.73 \(\pm\) 1.55 & 3.03 \(\pm\) 1.69 \\ \cline{3-6}  & & pre & 4.03 \(\pm\) 2.33 & 3.13 \(\pm\) 1.86 & 2.41 \(\pm\) 2.02 & 3.39 \(\pm\) 3.03 \\ \cline{3-6}  & & post & 3.16 \(\pm\) 1.53 & 2.96 \(\pm\) 1.96 & 2.05 \(\pm\) 1.52 & 5.46 \(\pm\) 9.46 \\ \hline \multirow{2}{*}{\ \begin{tabular}{c} Hip Flexion–extension ROM \\ \end{tabular}  } & \multirow{2}{*}{Non-dominant} & pre & 57.53 \(\pm\) 2.84 & 58.11 \(\pm\) 3.97 & 9.67 \(\pm\) 3.69 & 10.75 \(\pm\) 3.15 \\ \cline{3-6}  & & post & 52.09 \(\pm\) 4.04 \({}^{\star}\), \(\dagger\) & 57.22 \(\pm\) 3.29 & 6.75 \(\pm\) 3.85 \({}^{\star}\), \(\dagger\) & 11.74 \(\pm\) 5.22 \\ \cline{3-6}  & & pre & 58.17 \(\pm\) 3.71 & 57.42 \(\pm\) 3.45 & 9.86 \(\pm\) 3.35 & 10.75 \(\pm\) 5.48 \\ \cline{3-6}  & & post & 50.99 \(\pm\) 3.49 \({}^{\star}\), \(\dagger\) & 56.76 \(\pm\) 4.45 & 7.42 \(\pm\) 3.59 \({}^{\star}\), \(\dagger\) & 10.55 \(\pm\) 4.00 \\ \hline \multirow{2}{*}{ \begin{tabular}{c} Hip Adduction–abduction ROM \\ \end{tabular}  } & \multirow{2}{*}{Non-dominant} & pre & 14.23 \(\pm\) 3.79 & 13.07 \(\pm\) 6.01 & 6.87 \(\pm\) 2.60 & 7.24 \(\pm\) 3.92 \\ \cline{3-6}  & & post & 13.51 \(\pm\) 3.57 & 13.40 \(\pm\) 5.96 & 7.49 \(\pm\) 3.53 & 6.64 \(\pm\) 3.62 \\ \cline{3-6}  & & pre & 15.04 \(\pm\) 3.58 & 13.10 \(\pm\) 4.12 & 6.29 \(\pm\) 2.41 & 7.11 \(\pm\) 3.70 \\ \cline{3-6}  & & post & 14.62 \(\pm\) 4.69 & 13.64 \(\pm\) 4.89 & 7.21 \(\pm\) 3.39 & 7.77 \(\pm\) 4.15 \\ \hline \multirowwith degenerative knee arthritis (DKA) during stair ascent and descent. The findings revealed significant improvements in postural stability, gait performance, and pain reduction among participants in the exercise group (EG) compared to those in the control group (CG). Stair ambulation imposes greater biomechanical demands than level walking, requiring increased hip, ankle, and knee joint flexion angles [40] and generating higher knee joint loads [41]. Prior research by [PERSON] and [PERSON] [42] indicated that DKA patients experience significant changes in joint angles during stair ascent, which can exacerbate symptoms due to increased knee joint loading. In the present study, after the 10-week intervention, EG participants exhibited a significant reduction in hip flexion angles during both stair ascent and descent, indicating enhanced hip joint stability. Additionally, knee joint flexion angles significantly decreased during stair ascent, suggesting improved knee joint stability, while knee flexion-extension ROM significantly increased during stair descent, reflecting enhanced knee joint flexibility. These contrasting adaptations highlight the differential biomechanical effects of unstable load training on stair ascent versus descent, warranting further investigation into the underlying mechanisms.