## 3 Results
### Spatiotemporal Gait Parameters  
Statistical analysis revealed significant differences between walking conditions for step length (F = 752.933, \(p\leq 0.001\), partial \(\eta^{2}\) = 0.960). Post-hoc comparisons indicated that, \begin{table}
\begin{tabular}{c c} \hline
**Spatiotemporal** & **Definition** \\
**Gait Parameters** & \\ \hline Step length (cm) & Distance between the heel strike of one side of the body and the heel strike of the contralateral side \\ Step width (cm) & Distance between the right and left foot \\ Foot rotation (\({}^{\circ}\)) & Angle between the longitudinal axis of the foot and the direction of walking \\ Step time (s) & Time within a gait cycle between the heel strike of one side of the body and the heel strike of the contralateral side \\ Cadence (step/min) & Frequency of steps per unit time \\ Stance phase (s) & Time within a gait cycle when the foot is in contact with the ground \\ Swing phase (s) & Time within a gait cycle during which the foot is not in contact with the ground \\ Double-stance phase (s) & Time of the load response and the pre-wing phase collectively \\ \hline \end{tabular}
\end{table} 
Table 1: Definition of the spatiotemporal parameters of gait recorded by the instrumented treadmill. compared to level walking, step length decreased as uphill and downhill walking became more demanding. Significant differences between walking conditions were found for step width (F = 57.802, \(p\leq 0.001\), partial \(\eta^{2}\) = 0.651). Compared to level walking, step width increased progressively during downhill walking, while only minor and non-significant changes were observed during uphill walking. There were significant differences in foot rotation across the different walking conditions (F = 33.199, \(p\leq 0.001\), partial \(\eta^{2}\) = 0.517). Post-hoc analysis revealed a significant increase in foot rotation during uphill walking compared to level walking. Additionally, foot rotation was lower in downhill walking, with significant differences observed only when comparing level walking to walking at a \(-10\%\) slope and a speed of 5.0 km h\({}^{-1}\) (refer to Table 2 for pairwise comparisons). Statistical analysis showed significant differences between walking conditions for step time (F = 362.858, \(p\leq 0.001\), partial \(\eta^{2}\) = 0.921) and cadence (F = 414.221, \(p\leq 0.001\), partial \(\eta^{2}\) = 0.930). Pairwise comparisons revealed that, in uphill walking conditions, step time significantly increased, and cadence decreased compared to level walking. Conversely, during downhill walking, step time significantly decreased, and cadence increased (refer to Table 2 for pairwise comparisons). Significant differences were observed for the stance phase (F = 505.472, \(p\leq 0.001\), partial \(\eta^{2}\) = 0.942), swing phase (F = 123.351, \(p\leq 0.001\), partial \(\eta^{2}\) = 0.799), and double-stance phase of gait (F = 750.943, \(p\leq 0.001\), partial \(\eta^{2}\) = 0.960) between the various walking conditions. Stance, swing, and double-stance durations increased in the uphill walking conditions and slightly decreased in downhill walking conditions compared to level walking (refer to Table 3 for pairwise comparisons).