A comparative electromyographic study of scapular stabilizing muscles during five main rehabilitation exercises

Abstract

ABSTRACT Objective To compare the surface electromyographic (sEMG) amplitude, activation ratio, and onset latency of the main scapular stabilizing muscles between five typical rehabilitative exercises. Design Twenty-seven healthy participants performed five scapular exercises [wall-slide (WS), wall push-up plus, prone horizontal abduction with external rotation (PHABER), external rotation in side-lying (ERSL), and low row] while simultaneously recording sEMG of serratus anterior (SA), middle trapezius (MT), lower trapezius (LT), and upper trapezius (UT). sEMG amplitudes, onset latencies, and activation ratios were calculated. Results PHABER showed an excellent UT/MT (0.43) and UT/LT (0.30) muscle balance with high (> 50% MVIC) MT and LT amplitudes, a low (< 20% MVIC) UT amplitude, and an early activation of the scapular stabilizing muscles (-474.7 to 89.9 ms) relative to UT. ERSL showed excellent UT/SA (0.26), UT/MT (0.32), and UT/LT (0.21) activation ratios; and along with LR and WS, showed early activation of the scapular stabilizing muscles (-378.1 to -26.6 ms). Conclusions PHABER presented optimal scapular neuromuscular control. Although ERSL, low row, and WS did not meet all the criteria associated with optimal scapular neuromuscular control, these exercises could be used in early stages of shoulder rehabilitation because they favor early activation of the scapular stabilizing muscles.