Shrug exercises combined with shoulder abduction improve scapular upward rotator activity and scapular alignment in subjects with scapular downward rotation impairment

The aim of this research was to investigate which shoulder abduction angle (30 degrees, 90 degrees, 150 degrees) during shrug exercise is superior for (1) activating the scapular upward rotators and (2) improving scapular and clavicular position in subjects with scapular downward rotation impairment. Twenty subjects performed shrug exercises at three different shoulder abduction angles (30 degrees, 90 degrees, 150 degrees) which were obtained and maintained actively. Surface EMG data were collected from the levator scapulae (LS), upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA) during shrug exercises. Scapular downward rotation index (SDRI) and clavicular tilt angle (CTA) were measured immediately after each shrug exercise. One-way repeated-measures analysis of variance was used to determine the significance. UT muscle activity was greater at 90 degrees and 150 degrees than at 30 degrees of shoulder abduction. UT/LS muscle activity ratio was greater at 90 degrees than at 30 degrees. LT and LT/LS increased as shoulder abduction angle increased. SA was greater at 150 degrees than at 30 degrees or 90 degrees. SA/LS was greater at 150 degrees than at 30 degrees. SDRI was lower at 90 degrees and 150 degrees than at 30 degrees. CTA was greater at 90 degrees and 150 degrees than at 30 degrees. In conclusion, shrug exercises at 90 degrees or 150 degrees of shoulder abduction angle may be advocated to activate scapular upward rotators, decrease SDRI, and increase CTA in patients with scapular downward rotation impairment. (C) 2014 Elsevier Ltd. All rights reserved.