Activation of the rotator cuff in generating isometric shoulder rotation torque

Yue Nan Jenp, Gerard A. Malanga, Eric S. Growney, Kai Nan An

研究成果: Article同行評審

53 引文 斯高帕斯(Scopus)


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° 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° of shoulder elevation in neutral rotation best isolated the subscapularis muscle. The infraspinatus-teres minor muscles were isolated in the sagittal plane with 90° 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.

頁(從 - 到)477-485
期刊American Journal of Sports Medicine
出版狀態Published - 1996

All Science Journal Classification (ASJC) codes

  • 骨科和運動醫學
  • 物理治療、運動療法和康復


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