A CASE STUDY ON ACTIVATION LEVEL OF ROTATOR CUFF MUSCLES USING ELECTROMYOGRAPHY AND ASSOCIATED MUSCLE FORCES

Abstract

Rotator cuff tears are among the most common shoulder injuries, making them an attractive topic of study. Yet, there is a lack of clear understanding of attributes associated with deep and superficial muscles when it is intended to study the recovery progress after rehabilitation. Through a systematic approach, this project investigates the activation of rotator cuff muscles using surface electromyography (sEMG) sensors. The team developed a strategic plan to investigate the precision of the NORAXON technology that is utilized in this study to ensure that it is capable of capturing small variations in shoulder motion. This is followed by a reliability analysis to ascertain reproducibility of the experiment. The levels of muscle activities for superficial and deep muscles are monitored to explore the impact of traditionally prescribed arm movements used for the rehabilitation of rotator cuff injuries. Furthermore, an analysis of forces generated in the muscles is done to provide better insight into the activation levels of rotator cuff muscles. The results were promising, with a competent technology and acceptable correlation associated with muscle activities across all subjects. Four common arm movements were studied; scaption generated a significant response in the targeted muscles, particularly of the supraspinatus. Results were conclusive across all subjects, and simulation also supported the experiment showing high activation levels for the supraspinatus. The teres minor also showed a significant contribution when performing external rotation at 90⁰ abduction. The outcome of this study is significant for this ongoing project as it identifies the most impactful exercises that ensure targeted muscles are being triggered. It also lays the groundwork for expanding the project to a clinical study focusing on the most effective arm movements in order to improve rehabilitation process and reduce pertinent cost.