[An electromyographic study on elevation of the shoulder joint].
To quantitatively analyze the electromyographic activity of the shoulder girdle muscles during elevation of the arm, the action potentials of nine muscles were integrated over 10-degree intervals of corresponding elevation angle. The trapezius, supraspinatus and deltoideus (anterior and middle fibers) muscles showed high activity and their activity increased in accordance with the magnitude of the elevation angle. The integrated EMG activity in the trapezius, supraspinatus and deltoideus (middle and posterior fibers) muscles increased as the plane of elevation was changed from the sagittal plane to the frontal plane. The correlation between the calculated work and the integrated EMG activity during scapular abduction from 0 to 90 degrees was analyzed. The regression coefficients of the trapezius, supraspinatus and deltoideus (anterior and middle fibers) muscles were higher than those of other muscles. The correlation coefficient of the supraspinatus was significantly lower than those of the trapezius, deltoideus and pectoralis major muscles.
Tomonaga
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Department of Orthopaedic Surgery, Nagasaki University School of Medicine, Japan.
D000293:Adolescent; D000328:Adult; D004576:Electromyography; D006801:Humans; D008297:Male; D009068:Movement; D012785:Shoulder Joint / Q000502:physiology*