Mechanisms that contribute to differences in motor performance between young and old adults
Mechanisms that contribute to differences in motor performance between young and old adults
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DOI：
10.1016/s1050-6411(02)00084-6
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发表时间：
2003-02-01
影响因子：
2.5
通讯作者：
Tracy, BL
中科院分区：
文献类型：
--
作者：
Enoka, RM;Christou, EA;Tracy, BL
这篇论文探讨了导致年轻人和老年人力量波动幅度差异的生理机制。由于肌力是运动单位活动的结果，潜在的机制既包括运动单位的属性，也包括运动单位群体的行为。然而，力量的波动不仅取决于个人的年龄，还取决于执行任务的肌肉组、肌肉收缩的类型和强度以及个人的身体活动状态。对单个激动者和拮抗者肌肉进行的计算机模拟和实验结果表明，力波动的差异不是由于运动单位抽动力、运动单位数量或激动者肌肉的不均匀激活所致，而是受到激动者和拮抗者肌肉中运动单位放电的变异性和共同调制的影响。由于力量波动的幅度不随肌肉的激活而线性变化，这些结果表明，尽管每种机制的边界条件仍有待确定，但多种机制导致了年轻人和老年人之间力量波动的差异。(C)2002爱思唯尔科学有限公司。保留所有权利。
This paper examines the physiological mechanisms responsible for differences in the amplitude of force fluctuations between young and old adults. Because muscle force is a consequence of motor unit activity, the potential mechanisms include both motor unit properties and the behavior of motor unit populations. The force fluctuations, however, depend not only on the age of the individual but also on the muscle group performing the task, the type and intensity of the muscle contraction, and the physical activity status of the individual. Computer simulations and experimental findings performed on tasks that involved single agonist and antagonist muscles suggest that differences in force fluctuations are not attributable to motor unit twitch force, motor unit number, or nonuniform activation of the agonist muscle, but that they are influenced by the variability and common modulation of motor unit discharge in both the agonist and antagonist muscles. Because the amplitude of the force fluctuations does not vary linearly with muscle activation, these results suggest that multiple mechanisms contribute to the differences in force fluctuations between young and old adults, although the boundary conditions for each mechanism remain to be determined. (C) 2002 Elsevier Science Ltd. All rights reserved.