Does EMG biofeedback training improve the scapular movement?
Subacromial or shoulder impingement is the most common cause of shoulder pain and accounts for 40% of shoulder disorders. Increased muscle activation of the upper trapezius and a lower activation of the lower trapezius and serratus anterior might lead to an abnormal scapular movement, which results in a decreased subacromial space.
Previous studies reported improved muscle activation patterns and an increased balance in the shoulder after the use of biofeedback. Although biofeedback has demonstrated to be effective, little is known about the acute effects of exercises with EMG biofeedback in prevention of shoulder impingement. Thus, this study aimed to investigate the effects of scapular stabilisation exercises with an EMG biofeedback training on scapular movement in healthy individuals.
23 healthy individuals participated in this study. Surface EMG was applied on the upper and lower trapezius, serratus anterior, and the lumbar paraspinals on the dominant side. The movement of the scapula was examined with a 3D magnetic tracking system. Each participant performed four different exercises, which targeted specific scapular stabilizing muscles. During these exercises, the participants looked at the projected EMG biofeedback protocol and were thereby able to control and isolate the targeted muscles. The study investigated the scapular muscles during an elevation task before and after the training.
The external rotation of the scapula during the elevation was significantly increased after the biofeedback training. However, the scapular upward rotation and the scapular posterior tilt did not improve after the biofeedback training. Thus, EMG biofeedback brought the scapula into a more externally rotated position during a humeral elevation and might be an effective treatment for patients with shoulder impingement.
> From: San Juan et al., J Biomech 49 (2016) 1881-1886. All rights reserved to Elsevier Ltd. Click here for the Pubmed summary.