CHARACTERISTICS OF SYNERGIC RELATIONS DURING ISOMETRIC CONTRACTIONS OF HUMAN ELBOW MUSCLES
CHARACTERISTICS OF SYNERGIC RELATIONS DURING ISOMETRIC CONTRACTIONS OF HUMAN ELBOW MUSCLES
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DOI：
10.1152/jn.1986.56.5.1225
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发表时间：
1986-11-01
影响因子：
2.5
通讯作者：
RYMER, WZ
中科院分区：
文献类型：
--
作者：
BUCHANAN, TS;ALMDALE, DPJ;RYMER, WZ
我们研究了三个正常人肘部肌肉的肌电图活动模式。当关节在不同方向上施加等距扭矩时，通过肌肉内电极同时记录7-10块横跨人类肘关节的肌肉的肌电活动。这些方向包括屈曲、伸展、内翻（肱骨内旋）、外翻（肱骨外旋）和几个中间方向。在手腕处产生的力覆盖了360度的范围，所有这些力都与前臂的长轴正交。观察到肌电活动水平随着关节扭矩的增加呈近似线性增加。所有肌肉在小于360度的范围内活动，大多数在小于180度的范围内活动。观察到肌电活动随着扭矩方向的变化有系统的变化，当在各种扭矩水平下的全角度范围内进行检查时，肌电活动随着扭矩大小的增加而简单地缩放。没有观察到单个肌肉单独活动的扭矩方向或扭矩大小。在所有病例中，关节扭矩似乎是由肌肉组合产生的。观察到肌肉肌电图达到最大值的方向与肘关节和相关肌肉的简单力学模型预测的最大机械优势方向相对应。内翻扭矩时，肌肉相对不活跃。这意味着肌肉并没有在这个方向上稳定关节，而可能是让韧带来承担负荷。一块肌肉的肌电活动与另一块肌肉的肌电活动的对比图显示了一些纯粹的协同作用，但大多数肌肉的协同激活模式更为复杂，并随扭矩方向而变化。这些模式的复杂性提高了协同效应是由任务决定的，可能没有独立存在的可能性。肱三头肌的两个头（内侧头-单关节肌肉和长头-双关节肌肉）的活动在扭矩大小和方向范围内密切相关，尽管肩部扭矩和肱三头肌长头所承受的力无疑是不同的。激活模式的相似性表明，弯头扭矩是主要的决定因素。讨论了肌肉协同作用的起源。这表明，他们是最好的理解基于一个模型，编码肢体扭矩在前运动神经元。（摘要删节为400字）
We studied the patterns of EMG activity in elbow muscles in three normal human subjects. The myoelectrical activity of 7-10 muscles that act across the human elbow joint was simultaneously recorded with intramuscular electrodes during isometric joint torques exerted over a range of directions. These directions included flexion, extension, varus (internal humeral rotation), valgus (external humeral rotation), and several intermediate directions. The forces developed at the wrist covered a range of 360 degrees, all orthogonal to the long axis of the forearm. The levels of EMG activity were observed to increase with increasing joint torque in an approximately linear manner. All muscles were active for ranges less than 360 degrees and most were active for less than 180 degrees. The EMG activity was observed to vary in a systematic manner with changes in torque direction and, when examined over the full angular range at a variety of torque levels, is simply scaled with increasing torque magnitude. There were no torque directions or torque magnitudes for which a single muscle was observed to be active alone. In all cases, joint torque appeared to be produced by a combination of muscles. The direction for which the EMG of a muscle reached a maximum value was observed to correspond to the direction of greatest mechanical advantage as predicted by a simple mechanical model of the elbow and relevant muscles. Muscles were relatively inactive during varus torques. This implies that the muscles were not acting to stabilize the joint in this direction and could have been allowing ligaments to carry the load. Plots of EMG activity in one muscle against EMG activity in another demonstrate some instances of pure synergies, but patterns of coactivation for most muscles are more complicated and vary with torque direction. The complexity of these patterns raises the possibility that synergies are determined by the task and may have no independent existence. Activity in two heads of triceps brachii (medial head--a single-joint muscle and long head--a two-joint muscle) covaried closely for a range of torque magnitudes and directions, though shoulder torque and hence the forces experienced by the long head of the triceps undoubtedly varied. The similarity of activation patterns indicates that elbow torque was the principal determining factor. The origins of muscle synergies are discussed. It is suggested that they are best understood on the basis of a model which encodes limb torque in premotor neurons.(ABSTRACT TRUNCATED AT 400 WORDS)