1 Indiana University, Indianapolis, IN, USA.
2 University of Michigan, Ann Arbor, MI, USA.
Neurorehabil Neural Repair. 2019 Jan;33(1):47-58. doi: 10.1177/1545968318817825. Epub 2018 Dec 29.
High-intensity, variable stepping training can improve walking speed in individuals poststroke, although neuromuscular strategies used to achieve faster speeds are unclear. We evaluated changes in joint kinetics and neuromuscular coordination following such training; movement strategies consistent with intact individuals were considered evidence of recovery and abnormal strategies indicative of compensation.
A total of 15 individuals with stroke (duration: 23 ± 30 months) received ≤40 sessions of high-intensity stepping in variable contexts (tasks and environments). Lower-extremity kinetics and electromyographic (EMG) activity were collected prior to (BSL) and following (POST) training at peak treadmill speeds and speeds matched to peak BSL (MATCH). Primary measures included positive (concentric) joint and total limb powers, measures of interlimb (paretic/nonparetic powers) and intralimb compensation (hip/ankle or knee/ankle powers), and muscle synergies calculated using nonnegative matrix factorization.
Gains in most positive paretic and nonparetic joint powers were observed at higher speeds at POST, with decreased interlimb compensation and limited changes in intralimb compensation. There were very few differences in kinetic measures between BSL to MATCH conditions. However, the number of neuromuscular synergies increased significantly following training at both POST and MATCH conditions, indicating gains from training rather than altered speeds. Despite these results, speed improvements were associated primarily with changes in nonparetic versus paretic powers.
Gains in locomotor function were accomplished by movement strategies consistent with both recovery and compensation. These and other data indicate that both strategies may be necessary to maximize walking function in patients poststroke.
高强度、变步幅训练可以提高脑卒中后患者的步行速度，但目前尚不清楚用于实现更快速度的神经肌肉策略。我们评估了这种训练后关节动力学和神经肌肉协调性的变化；与完整个体一致的运动策略被认为是恢复的证据，而异常的策略则表明存在代偿。
共 15 名脑卒中患者（病程：23±30 个月）接受了≤40 次高强度、变步幅的训练（任务和环境）。在跑步机最高速度和与峰值 BSL 匹配的速度（MATCH）下，采集下肢动力学和肌电图（EMG）活动，分别在训练前（BSL）和训练后（POST）进行。主要测量指标包括正（向心）关节和总肢体功率、肢体间（患侧/健侧功率）和肢体内补偿（髋关节/踝关节或膝关节/踝关节功率）的测量值，以及使用非负矩阵分解计算的肌肉协同作用。
在 POST 时，在较高速度下观察到大多数正性患侧和健侧关节功率的增加，同时肢体间补偿减少，肢体内补偿有限。在 BSL 到 MATCH 条件下，动力学测量值的差异很小。然而，在 POST 和 MATCH 条件下，神经肌肉协同作用的数量显著增加，这表明训练有收益，而不是速度改变。尽管有这些结果，但速度的提高主要与健侧和患侧功率的变化有关。
运动功能的提高是通过与恢复和代偿一致的运动策略实现的。这些和其他数据表明，在脑卒中后患者中，两种策略都可能是最大化步行功能的必要条件。
