Electromyographic activity of scapular stabilizers muscles during push up exercise variations in subjects with and without shoulder impingement syndrome

Abstract

Closed Kinetic Chain exercises (CKC) are commonly employed in the rehabilitation of Shoulder Impingement Syndrom (SIS), painful condition common in athletes, related to muscle imbalance between the scapular stabilizers. The objectives of this study was  to compare the electromyographic activity (EMG) of the serratus anterior (SA), upper trapezius (UT), middle trapezius (MT) and lower trapezius (LT) and the electromyographic ratio during exercises push up in asyntomatic individuals and SIS. Thirty volunteers divided into two groups: control and SIS. The EMG activity was recorded during the knee push up (KPU) and one-arm knee push up (OKP), on stable and unstable bases of support.  For statistical inference was used an analysis of variance (ANOVA) and Tukey post-test, with significance level of 5%. The unstable surface provided in decreased activation of SA in both groups and increased ratios of UT / SA (p < .03) in the SIS. The results of the study showed different responses of muscle activation, in individuals with asymptomatic and SIS, face to conditions that alter the stability of the base of support.