Selective activation of the infraspinatus muscle.
The infraspinatus muscle is thought to be a significant factor contributing to dynamic stabilization of the glenohumeral joint – therefore, strengthening exercises for the infraspinatus are commonly recommended as a part of rehabilitation programs for shoulder injuries. Nevertheless, there is still no consensus on the optimal shoulder position for selectively activating and strengthening the infraspinatus muscle.
The aim of this study was to determine activity in the infraspinatus, the middle trapezius and the posterior deltoid (the latters being possible compensatory muscles), and compare this between different shoulder external rotation exercises.
Side-lying external rotation in 90 degrees of shoulder flexion produced the greatest activity in the infraspinatus muscle, while activity in the both of compensatory muscles was minimized. Based on these results, this particular exercise position can be recommended to specifically strengthen the infraspinatus muscle > From Ha et al., J Athl Train 48 (2013) 346-352. All rights reserved to the National Athletic Trainers’ Association, Inc.
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