Characterization Of Pitching Kinematics and Risk Management Factors for Baseball Players with Shoulder Injuries

Shoulder injuries are common in major league baseball (MLB) players due to the explosive and unnatural throwing motion. The goal of the thesis was to provide quantitative information about factors that influence pitching outcomes, to better understand risk management of rotator cuff tears/injuries. Typically, shoulder injuries are due to the stress placed on the glenohumeral joint. While the kinetic chain and joint muscular forces produce the explosive overhead throw. There’s a vast range when it comes to shoulder injuries for pitchers. Rotator cuff injuries are common, and multiple factors contribute to either impingement/strains, tendinitis, or tears. The purpose of this study was to assess shoulder injuries sustained by MLB pitchers between 2015-2021, to identify changes between performance metrics, collected from a publicly available database for differences between pre and post injury. Selected factors of interest are: playing years in the league, injury history, average pitch types thrown for both preinjury and postinjury, release speed, release position in the x, y, and z directions, horizontal and vertical movement, horizontal and vertical positions of the ball when it crosses home plate (plate_x and plate_z), resultant velocities and accelerations, release spin rate, release extension, spin axis and return-to-sport determined by length of time spent on the injured list (IL) for more than 100 days or less than 100 days. Resultant velocities and accelerations were calculated using the provided metrics for velocity and acceleration in the x, y, z global dimensions. Resultant velocities were significant only for off-speed pitches (P= 0.053). Multiple linear regression analysis was preformed to relate ball flight kinematics (displacement, ball velocity, and acceleration), angular kinematics (spin rate and spin axis) per each pitch bin (e.g., fastballs, breaking balls, and off-speed pitches) to relate performance metrics found prior to injury and those after the sustained injury. Ball speed in miles per hour presented significance in the off-speed pitches, though spin rate was only significant for breaking ball pitches. Two distinct spin axis orientations were significant: breaking balls and off-speed pitches. The horizontal release position was significant for both fastballs and breaking balls than in the vertical release position which was significant for all pitch bins. From the analysis of variance, inferences were made to additional factors of interest that are out of the scope such as, kinematic sequence velocities and ground reaction forces.