Jenp Y N, Malanga G A, Growney E S, An K N
Department of Orthopedics, Mayo Clinic, Rochester, Minnesota 55905, USA.
Am J Sports Med. 1996 Jul-Aug;24(4):477-85. doi: 10.1177/036354659602400412.
This study compared and quantified electromyographic muscle activation of the rotator cuff with the isometric torque generated by performing shoulder rotation in various positions. Twenty healthy volunteers were tested in 29 shoulder positions. Using a Cybex II dynamometer synchronously with electromyography, surface electrodes were placed over the pectoralis major muscle and three parts of the deltoid muscle. Intramuscular wire electrodes were inserted into the four rotator cuff muscles. We found that the greatest external rotation isometric force is generated in the frontal and scapular planes in the neutral or full internal rotation positions. The sagittal, dependent, and the scapular plane with 45 degrees of elevation in rotational positions of either full or half external rotation generated the greatest torques for internal rotation isometric force. The rotator cuff muscles generated greatest electromyographic activity in neutral to midrotational positions. The scapular plane with 90 degrees of shoulder elevation in neutral rotation best isolated the subscapularis muscle. The infraspinatus-teres minor muscles were isolated in the sagittal plane with 90 degrees of shoulder elevation in a half externally rotated position. We were unable to isolate the supraspinatus muscle in any of these tested positions. These positions are recommended for manual muscle testing and for strengthening these muscles.
本研究比较并量化了在不同位置进行肩部旋转时，肩袖肌的肌电图肌肉激活情况与等长扭矩。20名健康志愿者在29个肩部位置接受测试。使用Cybex II测力计与肌电图同步，将表面电极置于胸大肌和三角肌的三个部分上方。将肌内线状电极插入四块肩袖肌中。我们发现，在中立位或完全内旋位的额状面和肩胛平面产生最大的外旋等长力。在完全或半外旋的旋转位，矢状面、下垂位以及肩胛平面45度抬高时产生最大的内旋等长力扭矩。肩袖肌在中立位至旋转中位产生最大的肌电图活动。在中立旋转位肩部抬高90度的肩胛平面能最佳地分离肩胛下肌。在半外旋位肩部抬高90度的矢状面能分离冈下肌-小圆肌。在这些测试位置中，我们无法分离冈上肌。推荐这些位置用于徒手肌力测试及这些肌肉的强化训练。
