Isolated Infraspinatus Atrophy Secondary to Suprascapular Nerve Neuropathy Results in Altered Shoulder Muscles Activity

Context:Isolated infraspinatus atrophy (IIA) is a common condition among overhead-activity athletes, which affects the hitting shoulder and is caused by suprascapular nerve injury. The loss of infraspinatus function could lead to altered activity of the glenohumeral and scapulothoracic muscles and compromise the optimal shoulder function.Objective:To assess the surface electromyographic (sEMG) activity patterns, relationships, and response latencies of relevant shoulder girdle muscles in professional volleyball players with IIA and in healthy control players.Design:Cross-sectional study.Setting:Research laboratory.Patients or Other Participants:Twenty-four male professional volleyball players (12 players with diagnosed IIA and 12 healthy players) recruited from local volleyball teams.Intervention(s):sEMG activity of anterior, middle and posterior deltoid, upper, middle and lower trapezius, and serratus anterior was recorded and evaluated during a movement of shoulder abduction in the scapular plane, monit...