Is the long sarcomere length responsible for non-traumatic supraspinatus tendinopathy? Potential novel pathophysiology and implications for physiotherapy.

Several theories have been proposed to explain the mechanism of non-traumatic supraspinatus tendinopathy, which causes rotator cuff tendinitis and rotator cuff ruptures. However, these theories have not addressed all potential causes of rotator cuff tendinopathy. We propose that the microanatomy of the supraspinatus muscle and its response to gravity is the mechanism that responsible for non-traumatic supraspinatus tendinopathy and rotator cuff tears. Gravity causes chronic traction to the supraspinatus muscle, which results in elongation in the sarcomere length. Elongated sarcomere length causes compression on the micro vessels in the muscle which compromises internal microcirculation of the muscle and tendon. Poor microcirculation triggers ischemia and ischemia triggers inflammation process in the muscle and the tendon. This results in a higher incidence of tendinopathy. We also propose a new physiotherapeutic approach that may provide improved healing for rotator cuff tendinopathy.