CHANGES IN SHOULDER MUSCLE ACTIVITIES IN SUBJECTS WITH A ROUNDED SHOULDER POSTURE DURING SCAPULAR POSTERIOR TILTING EXERCISE ON DIFFERENT SURFACES

Abstract

The current study aimed to determine whether there are different electromyographic (EMG) activities in the lower trapezius
and serratus anterior muscles of subjects with a rounded shoulder posture (RSP) during scapular posterior tilting (SPT) exercise
on four different surfaces. This study included 20 subjects with RSP. They all performed SPT exercise on four different
surfaces: a stable surface, upper body unstable surface, lower body unstable surface, and whole-body unstable surface. All
subjects’ EMG activities in the lower and upper trapezius muscles in the upper limb on the elevated side and in the upper
trapezius and serratus anterior muscles on the opposite side were determined during SPT exercise on four different surfaces,
respectively. Then, the ratios of the muscles’ EMG activities on both sides were compared. The results of the present study
show significant differences in EMG activities in the lower trapezius and serratus anterior muscles during SPT exercise on
four different surfaces (p < 0.05). The results of a post-hoc analysis showed significantly greater EMG activity values in the
lower trapezius and serratus anterior muscles during SPT exercise on the upper body unstable surface and whole-body unstable
surface (p < 0.05). Conclusively, SPT exercise performed in upper limb instability conditions is more favorable for increasing
lower trapezius muscle activity in patients with RSP.