Nonuniform activation of the agonist muscle does not covary with index finger acceleration in old adults.
Nonuniform activation of the agonist muscle does not covary with index finger acceleration in old adults.
复制标题
在老年人中，主动肌的不均匀激活并不与食指加速共变。
DOI：
10.1152/japplphysiol.00391.2002
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Enoka,RogerM
中科院分区：
文献类型：
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作者：
Laidlaw,DouglassH;Hunter,SandraK;Enoka,RogerM
本研究研究了年轻人和老年人食指在姿势(保持位置)和缓慢运动(位置跟踪)过程中，第一骨间背侧肌的浅部和深部以及拮抗肌第二掌侧骨间肌的激活模式。位置跟踪任务包括食指举起轻负荷(最大负荷的2.5%、10%和35%)，尽可能稳定地缩短和延长收缩。在两个任务中，稳定性被量化为食指加速的标准差。与年轻受试者(19-27岁)相比，老年受试者(62-72岁)在两个任务中的加速度波动更大，特别是在最轻负荷的情况下。两组受试者在位置保持任务中，第一背侧骨间肌浅层和深层的激活强度相近，而在位置跟踪任务的缩短和延长收缩过程中，深层激活的强度更大。因此，第一背侧骨间肌的不均匀激活与青年和老年受试者之间的加速度标准差差异无关。此外，在任何一组受试者在这些任务中，拮抗肌的平均协同激活水平和加速的标准差之间没有关联。因此，老年人在运动输出方面表现出的较大差异既不能用激动肌的不均匀激活解释，也不能用拮抗肌的平均共激活水平来解释。
This study examined the patterns of activation in the superficial and deep parts of the first dorsal interosseus muscle and in the antagonist muscle, second palmar interosseus, during postural tasks (position holding) and slow movements (position tracking) of the index finger performed by young and old adults. The position-tracking task involved the index finger lifting light loads (2.5, 10, and 35% of maximum) with shortening and lengthening contractions as steadily as possible. Steadiness was quantified in both tasks as the standard deviation of index finger acceleration. The fluctuations in acceleration during the two tasks were greater for the old subjects (62–72 yr) compared with young subjects (19–27 yr), especially with the lightest loads. The two groups of subjects activated the superficial and deep parts of first dorsal interosseus at similar intensities during the position-holding task, whereas the deep part was more active during the shortening and lengthening contractions of the position-tracking task. The nonuniform activation of first dorsal interosseus, therefore, was not associated with the difference in the standard deviation of acceleration between the young and old subjects. Furthermore, there was no association between the average level of coactivation by the antagonist muscle and the standard deviation of acceleration for either group of subjects across these tasks. Thus the greater variability in motor output exhibited by the older adults could not be explained by either the nonuniform activation of the agonist muscle or the average level of coactivation by the antagonist muscle.