The relationship between pitch velocity and shoulder distraction force and elbow valgus torque in collegiate and high school pitchers

Abstract Background The relationship between pitching velocity, shoulder distraction force, and elbow valgus torque is not well understood. The purpose of this study was to 1) determine the association between baseball pitching velocity and shoulder distraction force, 2) determine the association between baseball pitch velocity and elbow valgus torque. A sub-purpose was to determine these same associations within subgroups of college baseball and high school baseball pitchers. Methods Collegiate and high school baseball pitchers were biomechanically analysed, Variables extracted from the pitching reports included fastball pitching velocity, shoulder distraction force, and elbow valgus torque. Linear regression was performed to analyse the relationship between fastball velocity and shoulder and elbow kinetics. Subgroup analyses were then performed for college and high school pitches. Coefficients and 95% confidence intervals (95% CI) were calculated, with R squared (r2) utilized to assess model fit. Results A total of 70 pitchers (College: n = 23; High School: n = 47) were included in this study. There was a positive weak linear relationship between pitch velocity and shoulder distraction force(3.24 %BW (95% CI 2.07, 4.40) , r2 = 0.32, p Discussion Pitching velocity exhibited a weak positive linear relationship with both shoulder distraction force and elbow valgus torque. However, only high school pitchers were observed to have a weak positive linear relationship between pitching velocity and shoulder distraction force, while both college and high school pitchers exhibited a weak positive relationship between pitching velocity and elbow valgus torque. These findings suggest that older pitchers may attenuate shoulder forces with increased pitching velocity due to physical maturity or increased pitching mechanical skill in comparison to younger pitchers. Level of Evidence Basic Science Study; Kinesiology.