Effects of Weight, Height, and Related Parameters on Elbow Varus Torque in Collegiate and Professional Baseball Pitchers.

Abstract

Background: Ulnar collateral ligament (UCL) injuries are prevalent in baseball pitchers. Epidemiological research has identified body weight as a risk factor.

Purpose/hypothesis: The purpose of this study was to evaluate the influence of anthropometric characteristics (ie, height, weight, and related measures) on elbow varus torque in adult baseball pitchers. It was hypothesized that weight and height would each be correlated with elbow varus torque.

Study design: Descriptive laboratory study.

Methods: Anthropometric and fastball pitching biomechanical data from 627 collegiate and professional pitchers were analyzed. Elbow varus torque during pitching was computed using the pitcher's weight, height, pitching biomechanics, and inverse dynamics. Pearson correlation coefficients were calculated between individual anthropometric characteristics and elbow varus torque. Stepwise multivariate regression was also performed.

Results: There was a strong correlation of elbow varus torque with weight and weight × height; a moderate correlation with body mass index; and a weak correlation with forearm length, height, and upper arm length. Stepwise regression explained 38% of elbow varus torque, with weight as the main contributor.

Conclusion: Larger pitchers, particularly heavier pitchers, produced greater elbow varus torque.

Clinical relevance: Pitchers with a greater weight may be at a higher risk of UCL injuries.