Few studies have prospectively examined injury rates in high school softball and baseball players. While many descriptive studies have been conducted to determine the risk of injury in competitive baseball, particularly upper extremity injury, none have prospectively assessed the risk of injury in softball athletes. While prior retrospective studies have found an association between overhead athletes’ arm injuries, and range of motion (ROM) deficits in shoulder external rotation (ER), internal rotation (IR), total rotation ROM (ER+IR)m and horizontal adduction (HA), few prospective studies have examined these and other risk factors in youth softball and baseball.