Kim Yushin, Bulea Thomas C, Damiano Diane L
Department of Sports Rehabilitation, Cheongju University, Cheongju, South Korea.
Neurorehabilitation and Biomechanics Research Section, Rehabilitation Medicine Department, National Institutes of Health, Bethesda, MD, United States.
Front Hum Neurosci. 2022 Sep 23;16:976100. doi: 10.3389/fnhum.2022.976100. eCollection 2022.
Despite external environmental changes in walking, such as manipulating gait speed, previous studies have shown that the underlying muscle synergy structures (synergy weights or vectors) rarely vary. The purpose of this study is to examine if external environmental changes to the walking task influence muscle synergies in children with cerebral palsy (CP) and/or typical development (TD). To identify muscle synergies, we extracted muscle synergies from eight children with CP and eight age-matched TD in three treadmill walking conditions, e.g., baseline (adjusted to individual comfortable walking speed), variable speed (VS), or restricted foot width (RW). Then, we grouped similar muscle synergies using k-mean clustering and discriminant analyses from all datasets of individual synergy structures. Proportion tests exhibited six clusters of muscle synergies predominantly arising from children with CP and four clusters from children with TD. Also, the proportion of muscle synergies was significantly different in four of the CP-preferred clusters across conditions. Specifically, the proportion of the baseline condition was significantly different from VS and RW conditions in one and two clusters, respectively. The proportion was significantly different between VS and RW conditions in four clusters. Cadence and step lengths differed across conditions but not groups which makes the group differences in proportion even more notable. In contrast, step width, while significantly lower in CP, did not differ across conditions. Our findings demonstrate that muscle synergies in children with CP are more sensitive to changes in the external walking environment than in typically developing children.
尽管在行走过程中存在外部环境变化，如改变步态速度，但先前的研究表明，潜在的肌肉协同结构（协同权重或向量）很少变化。本研究的目的是检验行走任务的外部环境变化是否会影响脑瘫（CP）儿童和/或发育正常（TD）儿童的肌肉协同作用。为了识别肌肉协同作用，我们在三种跑步机行走条件下，即基线（调整为个体舒适行走速度）、变速（VS）或受限步幅宽度（RW），从8名CP儿童和8名年龄匹配的TD儿童中提取了肌肉协同作用。然后，我们使用k均值聚类和判别分析对个体协同结构的所有数据集进行分组，以确定相似的肌肉协同作用。比例测试显示，主要来自CP儿童的肌肉协同作用有6个聚类，来自TD儿童的有4个聚类。此外，在CP儿童占优势的4个聚类中，不同条件下肌肉协同作用的比例存在显著差异。具体而言，基线条件下的比例在1个和2个聚类中分别与VS和RW条件下的比例有显著差异。在4个聚类中，VS和RW条件下的比例存在显著差异。步频和步长在不同条件下有所不同，但在不同组之间没有差异，这使得比例上的组间差异更加显著。相比之下，步幅宽度虽然在CP儿童中显著更低，但在不同条件下没有差异。我们的研究结果表明，与发育正常的儿童相比，CP儿童的肌肉协同作用对外部行走环境的变化更敏感。
