Factors that Increase Elbow Stress in the Throwing Athlete: a Systematic Review of Biomechanical and Motion Analysis Studies of Baseball Pitching and Throwing

Purpose of Review Elbow pain poses a unique challenge in the throwing athlete. Due to the high levels of elbow stress during the throwing motion, elbow injuries are common in throwers of all ages. There are several postulated factors believed to contribute increased stress to the throwing elbow. A detailed review of the published biomechanical studies evaluating the stresses experienced by the throwing elbow is needed. Here, we review these biomechanical studies to extrapolate the contributing factors that increase stress, the modifications that may reduce such stress, and the post-injury rehabilitation that optimizes outcomes and reduces recurrence. Recent Findings The biomechanical forces on the elbow have been further investigated delineated in recent work. Rotational malalignment of the shoulder, including both GIRD and decreased adduction, increases torque experienced by the elbow during pitching motions. Exact interactions between lower extremity, lumbopelvic or trunk rotation, and elbow forces during throwing remain uncertain with mixed results in recent literature. Pitch types may influence elbow stresses although delivery mechanism and distance thrown do not. Summary Several biomechanical factors influence the stresses imparted on the throwing elbow. Throwing volume, proper throwing mechanics, and appropriate rehabilitation are likely to be to be the most influential on mitigating unnecessary stresses imparted to the elbow in the throwing athlete. A proper understanding of these factors may reduce the occurrence of these injuries in this population. Moreover, an understanding of proper rehabilitation following injury may ensure optimized results and reduce recurrence.