Motor-unit recruitment during long-term isometric and wrist motion contractions: a study concerning muscular pain development in computer operators
Motor-unit recruitment during long-term isometric and wrist motion contractions: a study concerning muscular pain development in computer operators
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DOI：
10.1016/s0169-8141(02)00128-2
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发表时间：
2002-10-01
影响因子：
3.1
通讯作者：
Zhang, QX
中科院分区：
文献类型：
--
作者：
Forsman, M;Taoda, K;Zhang, QX
与工作有关的肌肉骨骼疾病常见于从事轻至中度重复性工作的工人，例如计算机操作员。灰姑娘假说提出，慢性肌肉疼痛的发展是由于过度使用属于低阈值运动单位的纤维。该假说要求存在运动单位，这些运动单位（1）在足够长的时间内处于活动状态，以实际损害纤维，（2）在不同的姿势和整个运动过程中处于活动状态。在这项研究中，8名受试者在25分钟静态低水平收缩和全方位腕关节运动期间记录了指总伸肌（EDC）运动单位的放电行为。结果显示，在长期测量中，一个运动单位持续活跃，而大多数运动单位随着时间的推移部分活跃，即，EDC中的运动单位可能持续活动至少25分钟的低水平静态收缩，但运动单位替代似乎频繁发生。在腕关节运动过程中，运动单位被发现活跃在所有受试者的运动的所有阶段。因此，结果不拒绝EDC肌肉的灰姑娘假设。
Work-related musculoskeletal disorders are frequent in workers with light to moderate load repetitive work, e.g. computer operators. The Cinderella hypothesis proposes that the development of chronic muscular pain is due to an overuse of fibers belonging to low-threshold motor units. The hypothesis requires that there exist motor units that are active (1) for a time long enough to actually damage the fibers, and (2) in different postures and throughout movements. In this study, the firing behavior of motor units in the extensor digitorum communis (EDC) muscle was registered in eight subjects during a 25-min static low-level contraction and during full range of motion wrist movements.The results showed one motor unit that was continuously active throughout the long-term measurement, while the majority of the motor units were partially active over time, i.e. it is possible for motor units in the EDC to be continuously active for at least 25 min of a low-level static contraction, but motor unit substitution seems to occur frequently. During the wrist motion, motor units were found active in all phases of the movements in all subjects. Hence, the results do not reject the Cinderella hypothesis for the EDC muscle.