견관절 외전 각도에 따른 중간 및 하부 승모근의 근 활성도 비교

A Comparison of EMG Activity for Middle and Lower Trapezius Muscle According to Shoulder Abduction Angles

The purpose of this study was to compare electromyography (EMG) activity for the middle and lower trapezius muscle according to various shoulder abduction angles. Thirty healthy male subjects were recruited for this study. Each subject performed three repetitions of horizontal abduction at 75˚, 90˚, 125˚, 160˚, and 180˚ of shoulder abduction angle in a prone position. Surface EMG activity was recorded from the middle and lower trapezius while the subjects held for five seconds at a predetermined position. The EMG activity was normalized using the maximal voluntary isometric contraction (MVIC) elicited using a manual muscle testing technique. A repeatedly measured ANOVA was performed by Bonferroni's post hoc test. The EMG activity of the middle and lower trapezius was significantly different among shoulder abduction angles (p<.05). The greatest level of muscle activity for the middle and lower trapezius were demonstrated at 90˚and 160˚of shoulder abduction angle, respectively. These results suggest that middle and lower trapezius strengthening exercise and manual muscle testing should be performed at different shoulder abduction angles.