어깨뼈 내밈 운동 시 운동 자세와 어깨관절 굽힘각도에 따른 앞 톱니근과 위 등세모근의 근 활성도 비의 비교

Abstract

The purpose of this study was to investigate the activities of the serratus anterior (SA) and upper trapezius (UT) muscles during scapular protraction exercise with a dumbbell. Twenty-one healthy subjects with no medial history of shoulder pain or upper extremity disorders were recruited for this study. Subjects performed scapular protraction at <TEX>$90^{\circ}$</TEX> and <TEX>$130^{\circ}$</TEX> shoulder flexion with a dumbbell in supine and standing positions. The activities of the SA and UT were measured via surface electromyography (EMG) during 4 scapular protraction exercises. A 2 (angle) <TEX>${\times}$</TEX> 2 (position) repeated-measures analysis of variance (ANOVA) was used to compare the normalized activities of the SA and UT and the UT/SA ratio. The results showed that activities of both the SA and UT were the highest for the scapular protraction exercise at <TEX>$130^{\circ}$</TEX> shoulder flexion in the standing position. However, the UT/SA ratio was the lowest for the exercise at <TEX>$90^{\circ}$</TEX> shoulder flexion in supine position. Therefore, for selective activation of the SA muscle, we recommend performing the scapular protraction exercise with a dumbbell in the supine position at <TEX>$90^{\circ}$</TEX> shoulder flexion.