Lower limb joint angles and their variability during uphill walking.

Abstract Background Adaptation of the walking pattern to uphill walking demands immediate coordination between the lower limb segments. Nonetheless, knowledge about individual joints’ responses and variability in response to the new slope angles are missing. Aims This study investigated the impacts of uphill walking on the ankle, the knee and the hip joints angles and their variability. Methods Twenty-three collegiate athletes (age: 22.04 ± 3.43years, body mass: 62.14 ± 9.26Kg, height: 168.29 ± 7.06 cm) walked on an inclined treadmill at 0 ° (level walking -LW), 5 ° (low-slope-walking -LSW), and 10 ° (high-slope-walking -HSW) slopes at their preferred walking speed (4.2 ± 0.51 km.h-1). The ankle, knee and hip joints angles and their variability (standard deviations) were calculated and analysed throughout the gait cycles in LW, LSW, and HSW. Results Repeated measure ANOVA portrayed significant differences between the ankle joint angles in sagittal (p  .14), frontal (p  .14), and transverse (p  .01) planes. In the knee joint, the sagittal (p  .14), frontal (p  .14), and transverse (p  .14) angles were significantly different (p  .14), frontal (p  .14), and transverse (p  .14) angles were significantly different. Ankle angle variability was significantly different in sagittal (P  .14), frontal (p = .002, ηp2>.14) and horizontal (P  .14) planes, as well as knee joint angle variability in sagittal, frontal and horizontal planes p  .14. The hip joint variability was considerably different in sagittal (p = .031, ηp2>.14) and horizontal (p  .14) planes. Conclusion Uphill walking involves further modifications in the ankle, knee and hip joints angle to adjust the whole-body movements to a new slope. This adjustment resulted in a firm base of support, provided by the ankle, to regulate the knee and hip joints modifications. Nevertheless, it caused less ankle movement variability and could end up with injuries over long-term uphill walking.