Effects of selected rehabilitative exercises on external rotator muscles and trapezius muscles of masonry workers.

BACKGROUND: Masonry workers engaged in occupational work-activities have high risk of shoulder injury that often develops to functional loss and disability. Rehabilitative exercises (REs) have potential for slowing this development.

OBJECTIVE: The objective is to study the effects of three selected REs on integrated electromyography activations of the external rotator muscles and trapezius muscles of masonry workers.

METHODS: Ten subjects, masonry workers having shoulder pain, have volunteered for this study. Each subject performs three selected REs: (1) Prone horizontal abduction at 90° with full external rotation with thumb right up. (2) Side lying external rotation (ER) with elbow on the trunk. (3) ER at 90° abduction and elbow flexion at 90° in standing position. Selection of REs is based on their superior performance in earlier studies. Electromyography (EMG) differences among the exercises are tested for statistical significance.

RESULTS: A cross comparison of REs shows that exercises (1) and (3) produce high rotator cuff synergy, an average of infraspinatus and teres-minor activities. Exercise (3) minimizes the risk of subacromial impingement by presenting the least posterior deltoid activity. However, exercise (1) reduces the risk of abnormal scapular movement by producing higher middle trapezius and lower trapezius activities than upper trapezius activity.

CONCLUSION: The results provide basic information to design appropriate rehabilitation programs for masonry workers having shoulder pain.