Lawson, L, Klare, K, Uhl, T, and Nitz, A; University of Kentucky, Lexington, Kentucky, USA. ltlawson30@hotmail.com.

PURPOSE: Limited evidence exists that delineates muscular demands while performing passive (PROM), active assistive (AAROM) and active range of motion (AROM) exercises. The purpose of this study was to evaluate the electromyographical activity (EMG) in shoulder musculature as it is displayed throughout the progression of thirteen common shoulder rehabilitation exercises. SUBJECTS: A group of ten individuals with healthy shoulders participated in this study. Subjects were free of previous fracture, dislocation, or surgery and demonstrated full pain-free shoulder AROM. METHODS AND MATERIALS: The supraspinatus and infraspinatus were evaluated with fine wire electrodes. The anterior and posterior deltoid were evaluated with bipolar surface electrodes. All muscles were normalized to a maximal voluntary isometric contraction (MVIC). Subjects performed in counterbalanced order thirteen exercises: PROM (supine shoulder elevation with opposite hand, forward bow) AAROM (washcloth press-up with hands close, washcloth press-up with hands further apart, towel slide on table, scapular protraction with upper extremity on ball) AROM (supine can press-up, can press-up elevated on wedge, standing can press-up, wall slides, ipsilateral step-up with ball and step, ipsilateral step-up with step, ipsilateral shoulder flexion without a step). All EMG data was analyzed as percentage of MVIC using root mean squared amplitude. ANALYSIS: A non-parametric Friedman’s test for multiple conditions was used to compare the EMG activity across all exercises. A Wilcoxon post hoc analysis for two related pairs with a significance difference set at p <0.05 level. RESULTS: The Friedman’s test revealed significant differences across all exercises for each of the muscles (p<0.01). The post hoc analyses of the anterior deltoid and supraspinatus revealed significant differences in the progression from PROM (2, 3% MVIC respectively) to AAROM (7, 5%) to AROM (22, 20%) exercises. The posterior deltoid and infraspinatus EMG activity for the PROM (2, 3% respectively) and AAROM (3, 6%) were not significantly different, however, these exercises were significantly less than the AROM (6, 14%) exercises. CONCLUSIONS: In individuals with healthy shoulders, the selected shoulder exercises supported a progression of muscle activity from PROM to AAROM to AROM. As clinicians continue to treat patients following shoulder surgery, it is necessary to have a knowledge base of the demands on the injured tissues in order to prevent re-injury, delay recovery time, or damage additional structures. FUNDING SOURCE: University of Kentucky Malone Research Fund.

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