Selgrade Brian P, Chang Young-Hui
Department of Sports Medicine and Human Performance, Westfield State University, Westfield, MA, USA.
School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
medRxiv. 2025 Jul 21:2025.07.18.25331783. doi: 10.1101/2025.07.18.25331783.
People with amputation walk asymmetrically, leading to increased risk of intact leg injury. Split-belt treadmill walking using error augmentation has potential to correct this asymmetry. The purpose of this study was to assess how people with trans-tibial amputation and matched control subjects would adapt their limb forces to gradual onset split-belt treadmill walking. Consistent with prior split-belt results in sudden onset split-belt walking, we hypothesized that, after gradual onset split-belt walking, people with trans-tibial amputation and intact controls would display aftereffects in braking force but not propulsive force. We also hypothesized that both groups would have aftereffects in step length symmetry and double support, indicating predictive control of inter-leg coordination. People with trans-tibial amputation and control subjects displayed aftereffects in braking force, propulsive force, double support time, and step length symmetry. People with trans-tibial amputation displayed an aftereffect in step length opposite their baseline asymmetry. Both subject groups had aftereffects in fast (intact) leg forces that were larger for braking and smaller for propulsive forces than baseline. These findings indicate that gradual onset split-belt adaptation involves predictive control of inter-leg coordination and leg forces, which is not impaired by trans-tibial amputation. Predictive control of step length and braking is consistent with prior work, but these results suggest different adaptive control of propulsion than prior sudden onset research. This study shows that gradual onset split-belt walking may correct step length asymmetries in people with trans-tibial amputation, but increased intact leg braking aftereffects has potentially negative implications for correcting amputation-related kinetic asymmetries.
截肢者行走时不对称，导致健侧腿受伤风险增加。使用误差增强的分带式跑步机行走有可能纠正这种不对称。本研究的目的是评估经胫截肢者和匹配的对照组受试者如何将其肢体力量适应分带式跑步机的逐渐启动行走。与先前关于突然启动分带式行走的分带式研究结果一致，我们假设，在分带式行走逐渐启动后，经胫截肢者和健全对照组在制动力方面会出现后效应，但在推进力方面不会。我们还假设两组在步长对称性和双支撑方面都会出现后效应，这表明对双腿协调性有预测性控制。经胫截肢者和对照组受试者在制动力、推进力、双支撑时间和步长对称性方面均出现了后效应。经胫截肢者在步长上出现了与基线不对称相反的后效应。两个受试者组在快速（健全）腿力量方面都出现了后效应，制动力比基线时更大，推进力比基线时更小。这些发现表明，分带式行走逐渐启动的适应涉及对双腿协调性和腿部力量的预测性控制，而经胫截肢并不会损害这种控制。步长和制动方面的预测性控制与先前的研究一致，但这些结果表明推进力的适应性控制与先前的突然启动研究不同。本研究表明，分带式行走逐渐启动可能纠正经胫截肢者的步长不对称，但健侧腿制动后效应增加可能对纠正与截肢相关的动力学不对称产生潜在负面影响。
