Effect of Scapular Downward Rotator Stretch Exercises on Scapular Upward Rotator Activity During Arm Elevation in Subjects with Scapular Downward Rotation Syndrome

The purpose of this study was to investigate the effects of scapular downward rotator stretch exercises on muscle activity of the scapular upward rotators during arm elevation in subjects with scapular downward rotation syndrome. Sixteen people with scapular downward rotation syndrome were participated. To investigate the effectiveness of these stretching exercises, the surface electromyography (EMG) activity of levator scapula, upper trapezius, lower trapezius, and serratus anterior was measured at shoulder flexions of 90°, 120°, and 150° pre-and post-exercise. Two-way repeated-measures analysis of variance was used to determine the changes in muscle activities. A Bonferroni correction was performed on the post hoc test (α = 0.017). The activity of the levator scapular, upper trapezius, and serratus anterior muscle was increased (p < 0.017) as shoulder flexion angle changed. A comparison of muscle activity pre-and post-exercise and at different shoulder flexion angles showed that levator scapular and upper trapezius muscle activity was decreased at a shoulder flexion of 150° (p < 0.017). Serratus anterior muscle activity was decreased at shoulder flexion of 120° and 150° (p < 0.017). This study suggests that scapular downward rotator muscle stretching exercises should be performed before strengthening exercises to improve mobility in people with scapular downward rotation syndrome.