The vast majority of theses in this collection are open access and freely available. There are a small number of theses that have access restricted to the WWU campus. For off-campus access to a thesis labeled "Campus Only Access," please log in here with your WWU universal ID, or talk to your librarian about requesting the restricted thesis through interlibrary loan.
Date Permissions Signed
Date of Award
Department or Program Affiliation
Kinesiology: Exercise Science
Master of Science (MS)
Health and Human Development
San Juan, Jun G.
Suprak, David N. (David Nathan)
Buddhadev, Harsh H. (Harsh Harish)
Background: The shoulder is injury prone and subacromial impingement syndrome (SAIS) is one of the most diagnosed causes of pain in the region.
Objective: The purpose of this study was to investigate muscle activity between healthy and SAIS shoulders on the same subject and to understand the effectiveness of EMG biofeedback (EBFB) on bilateral overhead movements.
Design: Ten participants (7 male), that tested positive for 2/3 SAIS clinical tests, volunteered for the study. Bilateral muscle activity was measured via electrodes on the Upper Trapezius (UT), Lower Trapezius (LT), Serratus Anterior (SA), and Lumbar Paraspinals (LP). Kinematic testing involved 3 continuous bilateral scapular plane overhead movements before and after EBFB. EBFB consisted of 10 bilateral repetitions of I, W, Y, and T exercises focused on reducing UT and increasing LT and SA activity.
Results: Prior to EBFB, no significant difference in muscle activity was present between sides. A significant main effect of time indicated that after EBFB both sides exhibited reduced UT activity at 60° (p = 0.003) and 90° (p = 0.036), LT activity was increased at all measured humeral angles (p < 0.0005), and SA muscle activity was increased at 110° (p = 0.001).
Conclusion: EBFB in conjunction with scapular based exercise effectively alters muscle activity of healthy and impaired scapular musculature.
Scapula, Electromyography, Kinematics, Biofeedback, Impingement
Western Washington University
Subject – LCSH
Shoulder--Wounds and injuries; Electromyography; Biofeedback
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.
Mackay, Eliot, "The Effect of EMG Biofeedback Training on Muscle Activation in an Impingement Population" (2021). WWU Graduate School Collection. 1055.