Early changes in muscle activation patterns of toddlers during walking
Early changes in muscle activation patterns of toddlers during walking
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DOI：
10.1016/j.infbeh.2005.10.001
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发表时间：
2006-04-01
影响因子：
2.1
通讯作者：
Ulrich, B
中科院分区：
文献类型：
--
作者：
Chang, CL;Kubo, M;Ulrich, B
几十年来，早期运动行为一直是发展学家关注的焦点。很少有研究明确指出这种协调模式背后的肌肉活动模式。我们的目的是阐明一种方法，客观地确定早期步行时肌肉放电的开始和抵消，并研究核心运动肌肉激活模式的出现。我们测试了8个蹒跚学步的孩子，当他们在地面上行走时，他们开始走路。3-6个独立的步骤)和三个月后的步行经验。表面电极监测腓肠肌、胫骨前肌、股四头肌和腘绳肌的活动。我们将肌电图信号简化为逐帧指定的“开关”，然后进行肌肉状态和共收缩分析，以及每个肌肉在多个周期内活动的概率分布。我们的研究结果清楚地表明，在走路开始时，肌肉活动是高度可变的，即使有，也很少有肌肉表现出重复的行为模式，无论是在幼儿体内还是在幼儿之间。变异性和共激活随着步行经验的增加而减少，但仍然不一致，相反，关节协调和终点（足部放置）参数的稳定性显著增加。我们认为这种趋势的出现是因为有大量的选择（肌肉组合）可用。蹒跚学步的孩子首先学会调动足够的力量来平衡和前进，但慢慢地发现如何优化这些资源。(c) 2005爱思唯尔公司版权所有。
Early locomotor behavior has been the focus of considerable attention by developmentalists over several decades. Few studies have addressed explicitly patterns of muscle activity that underlie this coordination pattern. Our purposes were to illustrate a method to determine objectively the onset and offset Of muscle firings during early walking and to investigate the emergence of patterns of activation of the core locomotor muscles. We tested eight toddlers as they walked overground at walking onset (max. of 3-6 independent steps) and after three months of walking experience. Surface electrodes monitored activity of the gastrocnemius, tibialis anterior, quadriceps, and hamstrings. We reduced EMG signals to a frame-by-frame designation of "on-off," followed by muscle state and co-contraction analyses, and probability distributions for each Muscle's activity across multiple cycles. Our results clearly show that at walking onset muscle activity was highly variable with few, if any, muscles showing recurring patterns of behavior, within or among toddlers. variability and co-activation decreased with walking experience but remained inconsistent, in contrast to the significant increase in stability shown for joint coordination and endpoint (foot placement) parameters. We propose this trend emerges because of the high number of options (muscle combinations) available. Toddlers learn first to marshal sufficient force to balance and make forward progress but slowly discover how to optimize these resources. (c) 2005 Elsevier Inc. All rights reserved.