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Force steadiness, muscle activity, and maximal muscle strength in subjects with subacromial impingement syndrome
Author(s) -
Bandholm Thomas,
Rasmussen Lars,
Aagaard Per,
Jensen Bente Rona,
Diederichsen Louise
Publication year - 2006
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.20636
Subject(s) - isometric exercise , medicine , subacromial impingement , physical medicine and rehabilitation , supraspinatus muscle , concentric , electromyography , physical therapy , rotator cuff , anatomy , geometry , mathematics
We investigated the effects of the subacromial impingement syndrome (SIS) on shoulder sensory‐motor control and maximal shoulder muscle strength. It was hypothesized that both would be impaired due to chronic shoulder pain associated with the syndrome. Nine subjects with unilateral SIS who remained physically active in spite of shoulder pain and nine healthy matched controls were examined to determine isometric and isokinetic submaximal shoulder‐abduction force steadiness at target forces corresponding to 20%, 27.5%, and 35% of the maximal shoulder abductor torque, and maximal shoulder muscle strength (MVC). Electromyographic (EMG) activity was assessed using surface and intramuscular recordings from eight shoulder muscles. Force steadiness was impaired in SIS subjects during concentric contractions at the highest target force level only, with muscle activity largely unaffected. No between‐group differences in shoulder MVC were observed. The present data suggest that shoulder sensory‐motor control is only mildly impaired in subjects with SIS who are able to continue with upper body physical activity in spite of shoulder pain. Thus, physical activity should be continued by patients with SIS, if possible, to avoid the loss in neural and muscle functions associated with inactivity. Muscle Nerve, 2006