Effect of Muscle Coactivation Strengthening for Rotator Cuff Tendinopathy

Rotator cuff tendinopathy (RCT) is the most frequent cause of shoulder pain. RCT is frequently termed as impingement syndrome, based on the underlying mechanism in which the subacromial space soft tissues (subacromial bursa, rotator cuff tendons and long head of the biceps tendon) get encroached under the coracoacromial arch when the arm is elevated. RCT contributes in the decrease in quality of life and function, and in inducing work incapacities and sleep disorders. Exercises, as conservative management, were shown to be effective in increasing function and in decreasing pain related to RCT. However, the lack of studies comparing different types of exercises (i.e. concentric, eccentric, scapular strengthening, proprioceptive, coactivation) is reported by many systematic reviews. One type of exercise, coactivation strengthening, could be more efficient. Coactivation strengthening implies a recruitment of the pectoralis major and the latissimus dorsi while performing regular strengthening. When theses muscles are recruited, the medio-inferior orientation of their tendons creates a force vector that limits the superior translation of the humeral head, thus limits the subacromial narrowing. The aim of this study is to evaluate the efficacy of coactivation strengthening exercises in patient with RCT compared to regular strengthening exercises. Forty-two participants diagnosed with RCT by an orthopaedic surgeon following a standardized protocol will be randomised to either coactivation or regular strengthening exercises. Participants will perform a 6-week exercise protocols. Outcomes will be measured at baseline, and at three, six, 12, 18 and 24 weeks. The primary outcome is function assessed with the Disabilities of arm, shoulder and Hand (DASH) questionnaire. Secondary outcomes focus on pain (visual analog scale), quality of life (Western Ontario Rotator Cuff Index), impression of change (Patient Global Impression of Change), subacromial distance (ultrasonography) a