Mechanical, Mechatronics and Manufacturing Engineering Department, UET Lahore, Faisalabad Campus, Faisalabad, Pakistan.
Department of Zoology, Government College University, Faisalabad, Pakistan.
Med Biol Eng Comput. 2022 Jul;60(7):2119-2132. doi: 10.1007/s11517-022-02587-z. Epub 2022 May 21.
Wearable ankle-foot orthoses (AFO) are widely prescribed clinically; however, their effect on balance control during ramp ascent/descent walk remains unknown. This study evaluates walking stability on a ramp during weight loading and unloading transitions of the stance phase with the effect of an adjustable AFO. An AFO is tuned firstly by tuning dorsiflexion only and then combining dorsi-plantarflexion adjustments. Gait stability is assessed from neuromotor input (centre-of-mass) and output (centre-of-pressure) responses obtained through motion-capture system and force platform. Stability margins are quantified from Nyquist and Bode methods illustrating the loading phase as stable and the unloading phase as unstable transition in all walking conditions. Further, a significant decrease in stability (p < 0.05) is observed by wearing AFO in its free mode which gets improved (p < 0.05) by tuning AFO. Results from neuromotor outputs also illustrated a strong interlimb correlation (p < 0.001), which implies a compensatory interaction between opposite limbs loading and unloading transitions. Neuromotor inputs illustrated unstable responses both in loading and unloading transitions and were observed to be greater in magnitudes compared with output margins. The overall results support the hypothesis that a wearable AFO affects gait stability during transitional phases, and by applying AFO adjustments, neuromotor balance control achieves stability margins closer to normal range.
可穿戴踝足矫形器（AFO）在临床上广泛应用；然而，其在斜坡上升/下降步行期间对平衡控制的影响尚不清楚。本研究评估了在姿势相的负重和卸载过渡期间，可调式 AFO 对斜坡行走稳定性的影响。首先通过调整背屈来调整 AFO，然后结合背屈-跖屈调整。通过运动捕捉系统和力台从神经运动输入（质心）和输出（压力中心）响应评估步态稳定性。稳定性裕度通过奈奎斯特和波特方法进行量化，表明在所有步行条件下，加载阶段是稳定的，卸载阶段是不稳定的过渡。此外，在自由模式下佩戴 AFO 会显著降低稳定性（p<0.05），通过调整 AFO 可以改善（p<0.05）。神经运动输出的结果还说明了强烈的肢体间相关性（p<0.001），这意味着在负重和卸载过渡期间，对侧肢体之间存在代偿性相互作用。神经运动输入在加载和卸载过渡期间呈现不稳定的响应，并且观察到其幅度大于输出裕度。总体结果支持这样的假设，即可穿戴式 AFO 会影响过渡阶段的步态稳定性，并且通过应用 AFO 调整，神经运动平衡控制可以达到更接近正常范围的稳定性裕度。
