Effects of Elastic Band applied Side-Lying Exercise Posture on Muscle Activities around the Scapula of Individuals with Scapular Downward Rotation Syndrome

Background: Many people do not know they have scapular downward rotation syndrome (SDRS) because they have no pain. However, SDRS may cause secondary issues such as neck pain, shoulder instability, and rotator cuff injury. Thus, individuals with SDRS should perform exercises that are suitable for SDRS. Purpose: The purpose of this study was to compare the muscle activity of the pectoralis major (PM) and the serratus anterior (SA) during shoulder-strengthening exercises in the side-lying position, standing position, and supine position using an elastic band to suggest an effective exercise posture for SDRS. Study design: Comparative, repeated measures design Methods: The subjects were thirty-nine adults with SDRS aged 25 to 40 years old were participated. We conducted a repeated measures analysis of variance by measuring muscle activities in SA, PM, while performing shoulder-strengthening exercises using an elastic band in three postures (side-lying, standing, and supine positions) in random order, using a surface electromyography device. One-way repeated measures analysis of the variance and a Bonferroni post hoc test were used. Results: The SA had the highest muscle activity in the order of side-lying position, standing position, and supine position, while the PM had low muscle activity in the side-lying position, supine position, and standing position in that order. Conclusions: The SA-intensive strengthening exercise for SDRD using an elastic band in the side-lying position was selected as the appropriate exercise.