The glenohumeral joint is a ball-and-socket joint with three degrees of freedom; these features give the joint an unstable axis of rotation because the joint has a small cross-sectional area (Andrade, Fleury, de Lira, Dubas, & da Silva, 2010). Coordinated action from the shoulder muscle complex is vital to efficient performance and reducing the risk of injury (Andrade et al., 2010; Yildiz et al., 2006). Previous studies divided handball throwing into three motions: cocking, acceleration, and followthrough (Wagner, Buchecker, von Duvillard, & Müller, 2010; Wagner, Pfusterschmied, von Duvillard, & Müller, 2011). Concerning the cocking phase, the shoulder internal rotators (IR) benefit from a stretch-shortening cycle in an eccentric motion followed by concentric muscle contraction, which directly affects the throwing velocity in the acceleration phase. In the follow-through phase, the role of external rotators becomes more crucial; these muscles must provide the shoulder joint with sufficient protection to prevent injury. Many studies have employed various methods for quantifying upper limb muscle quality to investigate