Institute of Design, Robotic, and Optimisation, Department of Mechanical Engineering, The University of Leeds, Leeds, UK.
Department of Mechanical Engineering, The Rice University, Texas, USA.
Gait Posture. 2020 Feb;76:98-103. doi: 10.1016/j.gaitpost.2019.10.034. Epub 2019 Nov 8.
Lower limb amputation is a major public health issue globally, and its prevalence is increasing significantly around the world. Previous studies on lower limb amputees showed analogous complexity implemented by the neurological system which does not depend on the level of amputation.
What are the differences in muscle synergies between healthy subjects (HS) and transfemoral amputees (TFA) during self-selected normal transient-state walking speed?
thirteen male HS and eleven male TFA participated in this study. Surface electromyography (sEMG) data were collected from HS dominant leg and TFA intact limb. Concatenated non-negative matrix factorization (CNMF) was used to extract muscle synergy components synergy vectors (S) and activation coefficient profiles (C). Correlation between a pair of synergy vectors from HS and TFA was analyzed by means of the coefficient of determination (R). Statistical parametric mapping (SPM) was used to compare the temporal components of the muscle synergies between groups.
the highest correlation was perceived in synergy 2 (S2) and 3 (S3) and the lowest in synergy 1 (S1) and 4 (S4) between HS and TFA. Statistically significant differences were observed in all of the activation coefficients, particularly during the stance phase. Significant lag in the activation coefficient of S2 (due mainly to activated plantarflexors) resulted in a statistically larger portion of the gait cycle (GC) in stance phase in TFA.
Understanding the activation patterns of lower limb amputees' muscles that control their intact leg (IL) and prosthetic leg (PL) joints could lead to greater knowledge of neuromuscular compensation strategies in amputees. Studying the low-dimensional muscle synergy patterns in the lower limbs can further this understanding. The findings in this study could contribute to improving gait rehabilitation of lower limb amputees and development of the new generation of prostheses.
下肢截肢是一个全球性的重大公共卫生问题，其在全球范围内的患病率显著增加。先前对下肢截肢者的研究表明，神经系统执行的复杂性与截肢水平无关。
在自我选择的正常瞬态行走速度下，健康受试者（HS）和股骨截肢者（TFA）的肌肉协同作用有何不同？
13 名男性 HS 和 11 名男性 TFA 参与了这项研究。从 HS 主导腿和 TFA 完整腿采集表面肌电图（sEMG）数据。使用串联非负矩阵分解（CNMF）提取肌肉协同成分协同向量（S）和激活系数谱（C）。通过确定系数（R）分析 HS 和 TFA 之间一对协同向量的相关性。使用统计参数映射（SPM）比较组间肌肉协同的时间成分。
HS 和 TFA 之间 S2 和 S3 的相关性最高，S1 和 S4 的相关性最低。所有激活系数都存在统计学差异，尤其是在站立阶段。S2 的激活系数显著滞后（主要是由于激活的跖屈肌）导致 TFA 站立阶段在步态周期（GC）中占比更大。
了解控制其完整腿（IL）和假肢腿（PL）关节的下肢截肢者肌肉的激活模式，可以更深入地了解截肢者的神经肌肉代偿策略。研究下肢的低维肌肉协同模式可以进一步加深对此的理解。本研究的发现有助于改善下肢截肢者的步态康复和新一代假肢的开发。
