How Does the Scapula Move during the Tennis Serve?

Purpose: This study aimed to describe the scapulothoracic kinematics during the tennis serve in highly skilled tennis players.
Methods: Thirteen male competitive players performed flat first serves while eight high-speed cameras recorded the three-dimensional trajectories of the 15 markers located on bony landmarks. The scapular position through the tennis serve was determined using the acromial marker cluster method.
Results: The results revealed that, during the cocking phase, the scapula externally rotated and posteriorly tilted to attain the maximal humeral external rotation. During the acceleration phase, the scapula upwardly rotated and anteriorly tilted to reach maximal racket head height. During the follow-through phase, the scapula internally and downwardly rotated, and posteriorly tilted, while the upper limb lowered and crossed the player's body.
Conclusions: The findings of this study provide new knowledge on the asymptomatic scapular motion during the tennis serve, which may help clinicians and coaches to understand the overhead sport motion mechanics and to better prevent and rehabilitate overhead shoulder injuries.