Shoulder Strength and its Relationship to Kinetics and Kinematics in Collegiate Baseball Pitchers

Pitching is an explosive dynamic movement that occurs in the sport of baseball. In order for a pitcher to throw an effective pitch, they must have sufficient strength, mobility, and durability to withstand the forces they experience on their throwing arm throughout the duration of the pitching motion. This study aims to determine relationships between strength values and pitching biomechanics that can lead to a better understanding of injury prevention and performance. 44 collegiate pitchers went through a protocol consisting of shoulder strength testing on an isokinetic dynamometer followed by pitching off a force-plate embedded mound during a motion capture session. Results of Pearson correlations between strength variable and pitching mechanics yielded a positive statistically significant relationship between elbow valgus at maximum external rotation (MER) and external rotation peak torque at 180°/sec (r=.30, p=.03). A small negative non-statistically significant relationship existed between maximum shoulder distraction force and max shoulder internal rotation. (r=-.1, p=.72). From the findings of this study, having the ability to produce high amounts of external torque can be beneficial to help accelerate the arm up to ball release, however higher amount of elbow valgus has been associated with elbow injury. Further research must investigate the relationship with elbow valgus and its relationship with injury and performance. Contrary to previous research, this study found a negative correlation between distraction force and internal rotation. Further research must identify both distraction and compressive forces acting upon the throwing arm in pitchers understand the effects of forces on each pitcher individually