Influence of scapular motion cues on trapezius muscle activity during Y exercise.

Abstract

The Y exercise is a therapeutic exercise facilitating lower trapezius muscle activity. To identify the effects of scapular movement cues (posterior tilt vs. posterior tilt with adduction/depression) on trapezius muscle activity during Y exercise. Fifteen healthy men without current shoulder pain performed general Y exercise; Y exercise with cues for scapular posterior tilt; and Y exercise with cues for scapular posterior tilt, adduction, and depression. Electromyography (EMG) data for the trapezius muscles were collected during Y exercise. The posterior tilt angle of the scapula was measured in the prone position with and without cues for scapular posterior tilt using an inclinometer application. The greatest lower trapezius muscle activity was observed during Y exercise with cues for scapular posterior tilt, while the greatest EMG activity of the upper trapezius was observed during Y exercise with cues for scapular posterior tilt, adduction, and depression (p< 0.05). Middle trapezius muscle activity did not significantly differ among the three Y exercise conditions (p= 0.175). Cues for scapular posterior tilt significantly increased the scapular posterior tilt angle in the prone shoulder abduction position (p= 0.007). Cues for scapular posterior tilt were most effective in facilitating lower trapezius muscle activity during Y exercise.