###### Abstract  
The shoulder is a unique and complex joint in the human body with three bones and four joints, which makes it the most unstable joint in the body due to the amount of motion. To improve approaches toward understanding the performance of overhead throwing movements, this systematic review summarizes the type of analysis related to shoulder biomechanics involving overhead sporting motions. A search of seven databases identified 33 eligible studies, which were subsequently scored using the Modified Coleman Methodology Score scale. A total of nine articles from badminton, seven from baseball, five from volleyball, five from tennis, three from cricket, and one from softball were reviewed. All 33 studies evaluated shoulder kinematics and 12 of them also investigated the forces and torques (kinetics). The most common methods used were 3D motion analysis (76%), digital video cameras (15%), electromagnetic tracking system (6%), and finally 3% used IMU sensors. Overall, shoulder external rotation during the back swing, internal rotation, and elbow extension during the forward acceleration phase were the strongest predictors of high velocity overhead throwing movement. The findings provide some useful insights and guidance to researchers in their future contribution to the existing body of literature on shoulder overhead throwing movement biomechanics. overhead throw; shoulder; biomechanics; kinematics; kinetics +
Footnote †: journal: Medical Imaging  
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Footnote 1: email: _Applied_  
Footnote †: journal: Medical Imaging  
During overhead throwing movements such as pitching in baseball, athletes typically utilize the stretch-shortening cycle with a larger hip-shoulder separation angle (X-factor) during the backswing, followed by trunk forward flexion, rapid shoulder internal rotation, elbow extension, and wrist flexion in a proximal-distal order during the arm acceleration phase to the instant of ball release/impact [5]. The pre-stretch of the active muscles stores elastic energy during eccentric loading and increases muscular force and power output during the final concentric phase of movement [6; 7]. Consensus was met among the authors across the literature on the baseball pitch, tennis serve, volleyball spike, and badminton smash, whereby the major contribution to faster ball release/post-impact speed comes from shoulder internal/external rotation [8; 9; 10; 11; 12; 13]. Another study reported that shoulder internal rotation contributes around 66% towards the development of racket head speed [14]. Previous studies have reported peak angular velocities as high as 2594\({}^{\circ}\)/s in volleyball jump spike [15], 2900\({}^{\circ}\)/s in tennis serve [16], 7148\({}^{\circ}\)/s in badminton jump smash [10], and 7200\({}^{\circ}\)/s in baseball pitching [17; 18]. These high angular velocities suggest shoulder internal rotation is important to speed development in overhead sporting motions, although methodological differences mean caution should be taken when comparing across studies on different sporting movements. The most common testing method for overhead movements is currently 3D motion analysis. Over the decades, the technology to accurately track human motion has developed exponentially and is widely applied in research and field settings. The approaches include capturing video with high-speed cameras, electromagnetic tracking, using wearable sensors such as inertial measurement unit (IMU), and infrared marker-based motion capture system. The evolution of automated marker-less 3D-tracking technology incorporating deep learning algorithms to solve computer vision problems is encouraging, but the accuracy is not well validated yet [19; 20]. Three-dimensional motion capture in a laboratory with markers on the performer's body segments tracked using multiple cameras is currently the gold standard to track continuous human motion [21]. In many cases, the continuous movement data are reduced to a number of discrete values for statistical analysis, which excludes potentially valuable information [22].