Association between pitching velocity and elbow varus torque

Background

While there has been an increase in the number of biomechanical studies and usage across baseball, there often remains a dichotomy between performance enhancement and injury reduction.

Objective

To identify which variables have the highest influence on elbow varus torque while controlling for pitch velocity. The secondary purpose was to evaluate a minimal data set prediction model derived from the identified biomechanical variables.

Method

A retrospective review was performed on baseball pitchers who underwent biomechanical evaluation. Analysis of covariance and prediction modeling for varus torque and fastball velocity were utilized.

Results

298 pitchers were included. Small associations were identified between the log of hip shoulder separation (0.12 (95 % CI: 0.01, 0.23), R²=0.10), maximum trunk rotation velocity (0.42 (0.15, 0.70), R²=0.12), trunk flexion at ball release (-0.11 (-0.20, -0.02), R²=0.10), and shoulder abduction at late cocking (-0.29 (-0.52, -0.06), R²=0.10) in relation to the log of elbow varus torque. The clinical prediction model for elbow varus torque resulted in poor prediction performance, calibration, and large error using minimal predictor variables (RMSE=1.15, R²=0.10, Calibration=0.78 (0.41, 1.15)).

Conclusion

Optimizing pitching efficiency by improving small aspects throughout the pitching delivery has potential to accomplish an improvement in velocity while maintaining lower levels of varus torque.