Electromyographic Analysis of Shoulder Joint Function of the Biceps Brachii Muscle During Isometric Contraction
Electromyographic Analysis of Shoulder Joint Function of the Biceps Brachii Muscle During Isometric Contraction
复制标题
等长收缩时肱二头肌肩关节功能的肌电图分析
DOI：
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发表时间：
1998
影响因子：
4.2
通讯作者：
S. Tamai
中科院分区：
文献类型：
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作者：
G. Sakurai;J. Ozaki;Y. Tomita;K. Nishimoto;S. Tamai
对11例健康男性肱二头肌在最大等长屈肩和外展30%以下时进行了肱二头肌头表面肌电图检查。通过使用锁定在前臂中性旋转的支具，使肘部相关的二头肌活动最小化。在24次肩部运动中，将肌电活动标准化为最大肌肉收缩的百分比。在所有检查的运动中检测到肌电图活动，表明二头肌作为肩部的屈肌和外展肌。对于大多数运动，肱二头肌的两个头在外旋期间比在内旋期间具有更高的活动。两个头的活动增加与手臂的高度，但没有表现出依赖肘的位置。在肩关节内旋过程中，长头仍处于活动状态。这些发现也表明肱二头肌是肩部的屈肌和外展肌，并且长头可以在上级和前部方向上起到肱骨头稳定器的作用。肱二头肌和三角肌的肌肉疲劳也被确定在30%的最大等长屈曲。所有肌肉的平均功率频率和匝数显著降低，振幅和综合肌电图增加。肱二头肌的平均功率频率的下降率大于三角肌，肱二头肌长头的振幅的增加率大于短头或三角肌。这些发现表明，肱二头肌的长头必须增加其机械输出，以保持手臂在更大程度上高于短头和三角肌。这可能是肌腱炎或长头断裂的原因之一。
Surface electromyography was performed for both heads of the biceps brachii in 11 healthy men while the muscles were under 30% maximum isometric shoulder flexion and abduction. Elbow related biceps activity was minimized by using a brace locked in neutral forearm rotation. Electromyographic activity was normalized as a percentage of maximal muscle contraction during 24 shoulder motions. Electromyographic activity was detected in all motions examined, suggesting that the biceps muscle acts as a flexor and an abductor of the shoulder. Both heads of the biceps muscle had higher activities during external rotation than during internal rotation for most motions. Activities of both heads increased with arm elevation, but showed little dependence on elbow position. The long head was still active during internal rotation of the shoulder. These findings also suggest that the biceps muscle is a flexor and an abductor of the shoulder, and that the long head can act as a humeral head stabilizer in superior and anterior directions. Muscle fatigue of the biceps and the deltoid muscle also was determined at 30% of maximum isometric flexion. All muscles had significantly decreased mean power frequency and turns count, and increased amplitude and integrated electromyography. The rate of decrease in mean power frequency was larger for the biceps than for the deltoid muscle, and the rate of increase in amplitude was larger for the long head of the biceps than for the short head or for the deltoid muscle. These findings suggest that the long head of the biceps must increase its mechanical output to keep the arm in elevation to a greater extent than do the short head and the deltoid muscle. This may be one of the causes of tendinitis or rupture of the long head.