Shoulder Range of Motion and Strength in the High School Baseball Pitcher: Influence on Elbow Biomechanics

Principal Investigator: Wendy J. Hurd, Ph.D. and Bernard F. Morrey, M.D.
Co-Investigator: Kenton R. Kaufman, Ph.D.
Advisor: Frank W. Jobe, M.D.
Funding Source: Major League Baseball

The overall goal of this work is to advance our understanding of how shoulder motion and strength impact elbow biomechanics during pitching. Aim 1 of the project is to quantify the upper extremity glenohumeral motion and shoulder girdle muscle strength of uninjured high school-aged baseball pitchers. For this aim we will measure bilateral shoulder range of motion and strength in 250 uninjured high school pitchers (Year 1). We will also videotape each individual while pitching to evaluate mechanics and determine eligibility for part 2 of the study.

Aim 2 of the project is to determine the influence of glenohumeral internal rotation motion and external rotator muscle strength on elbow biomechanics of uninjured high school-aged baseball athletes (Year 2). Objective 3D measurements of the pitching motion will be used to calculate ulnar collateral ligament (UCL) stress (calculated as peak elbow valgus torque) of 36 subjects. Subjects for Aim 2 are individuals identified in the first arm of the study who are divided into three groups: those with the poorest internal rotation motion, the poorest external rotator muscle strength, and subjects with the best motion and strength. Information derived from this investigation may result in findings from a simple clinical examination as a means of identifying individuals at increased risk for sustaining injury. Furthermore, if there are differences in medial elbow stress during pitching between these groups, this study would serve as justification for future clinical trials that evaluate the impact of a training intervention on baseball throwing biomechanics and injury rates.

** This is a multi-center collaboration between the Mayo and Kerlan-Jobe Clinics