Rotator cuff coactivation ratios in participants with subacromial impingement syndrome

Joseph B. Myers, Ji-Hye Hwang, Maria R. Pasquale, J. Troy Blackburn, Scott M. Lephart

The purpose of this study was to determine if abnormal rotator cuff coactivation and deltoid activation patterns exist in participants with subacromial impingement. Rotator cuff coactivation and middle deltoid activation was assessed during an elevation task. Participants with impingement exhibited decreased rotator cuff coactivation and increased middle deltoid activation at the initiation of elevation. The participants with impingement also had higher subscapularis–infraspinatus and supraspinatus–infraspinatus coactivation above the level of the shoulder where pain is typically present.

Individuals with subacromial impingement exhibit rotator cuff muscle coactivation and deltoid activation abnormalities during humeral elevation that might contribute to the encroachment of the subacromial structures associated with subacromial impingement.

Journal of Science and Medicine in Sport, 31 August 2008, online article ahead of print

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