Muscle activation after supervised exercises in patients with rotator tendinosis

Objective: To determine whether pain reduction induced by supervised exerci ses over several months results in increased maximal force and muscle activ ation. Design: Before-after trial. Participants: Ten patients with unilateral rotator tendinosis and more than 3 months' duration of pain. Intervention: Supervised exercises for 3 to 6 months. Outcome Measures: Maximal abduction force, muscle activation by surface ele ctromyogram (EMG), and pain were assessed during brief maximal voluntary is ometric contractions (MVC) before and after fatigue. EMG and pain were asse ssed during sustained submaximal contraction, performed with the shoulder 4 5 degrees abducted. The testing protocol was performed before and after sup ervised exercises. Results: In the afflicted shoulder, resting pain was reduced after supervis ed exercises and no longer differed from the unafflicted side. The increase in pain during contraction was almost the same before and after treatment. MVC force increased, but significant side differences remained. EMG increa sed for trapezius and deltoid muscles in both afflicted and unafflicted arm s. Fatigue development and recovery was unaltered by the exercise regimen. Conclusions: Pain reduction after supervised exercises was associated with an improved MVC force, but the side difference in maximal force generation was maintained. Muscle activity during maximal contraction increased in bot h the afflicted and unafflicted sides.