운동면과 어깨 관절 굽힘 각도가 어깨뼈 내밈 운동 시 어깨뼈 위쪽 돌림근에 미치는 영향

Abstract

PURPOSE: This study was to determine the effect of the plane of movement (sagittal plane vs. scapular plane) and shoulder flexion angle (<TEX>$90^{\circ}$</TEX> vs. <TEX>$130^{circ}$</TEX>) during scapular protraction exercises in healthy subjects by investigating the elecromyographic (EMG) activities of the serratus anterior (SA), upper trapezius (UT), and pectoralis major (PM). METHODS: Twenty-one healthy subjects participated in this study. Subjects performed maximal scapular protraction at the <TEX>$90^{\circ}$</TEX> or <TEX>$130^{\circ}$</TEX> shoulder flexion angles in the sagittal or scapular planes. Surface EMG was recorded from the SA and UT, and PM muscles. Dependent variables were examined by 2 (plane) <TEX>${\times}$</TEX> 2 (angle) repeated measures of analysis of variance (ANOVA). RESULTS: Significantly increased EMG activities in the SA and UT were found during scapular protraction exercise at the <TEX>$130^{\circ}$</TEX> shoulder flexion angle in the sagittal and scapular plane. Also, EMG activity of the PM significantly decreased at the <TEX>$130^{\circ}$</TEX> shoulder flexion angle in the sagittal plane and the <TEX>$90^{\circ}$</TEX> and <TEX>$130^{\circ}$</TEX> shoulder flexion in the scapular plane. CONCLUSION: we recommend scapular protraction exercise at the <TEX>$90^{\circ}$</TEX> shoulder flexion in the sagittal plane to selectively strengthen the SA muscle with limitation of upper trapezius activity and at the <TEX>$130^{\circ}$</TEX> shoulder flexion in the scapular plane to selectively strengthen the SA muscle with limitation of pectoralis major activity.