Muscle biopsy investigations on neuromuscular insufficiency of the rotator cuff: a contribution to the functional impingement of the shoulder joint

Abnormal isokinetic time-to-peak torque of the medial rotators of the shoulder in subjects with impingement syndrome

“…This kind of alteration was observed in the supraspinatus and deltoid in patients with shoulder impingement. 10 Another possible explanation is that the lateral rotators of the impingement group could not act eccentrically to decelerate the arm with the correct timing. Notably, a decrease in electromyographic activity of the infraspinatus and subscapularis during glenohumeral elevation was identified in subjects with impingement syndrome.…”

Electromyographic analysis of muscle function after latissimus dorsi tendon transfer

“…This thesis agrees with the latest biomechanics and pathogenesis of impingement. 17,19,30,31 Of note, we were unable to prove this thesis in our study. It remains unresolved whether the improved mobility, in fact, depends on the presumed better centralizing of the humeral head through the indirect effect of the latissimus dorsi muscle or whether it is at least partly the direct result of its full force.…”

Clinical significance of signal changes in the quadratus femoris muscle on MR

“…as can be seen in overuse syndrome injuries of the rotator cuff (21). Because of the advanced age of the subjects in this study, age-related QFM degeneration or disuse atrophy might have been responsible for loss of dynamic joint control.…”