Differences in Throwing Kinematics among Youth Baseball Pitchers and Football Quarterbacks

Abstract

The purpose of this study was to examine throwing kinematics of youth baseball pitchers and football quarterbacks. Eighteen pitchers (13.6 ± 1.3 years; 169.3 ± 8.0 cm; 62.3 ± 10.2 kg) and fifteen quarterbacks (14.3 ± 1.6 years; 174.9 ± 7.9 cm; 69.1 ± 14.0 kg) participated. Pitchers threw three fastballs to a catcher (46 ft; 14.0 m), while quarterbacks threw three 15 yard (13.7 m) passes to a receiver. Baseball pitchers displayed significantly greater trunk flexion at maximum external rotation (MER), ball release (BR) and maximum internal rotation (MIR) (p<0.001, p=0.003, p=0.007); as well as greater trunk rotation opposite throwing arm side at BR (p=0.048). Football quarterbacks displayed greater trunk rotation to throwing arm side at MER (p=0.002); shoulder horizontal adduction at FC (p=0.004); shoulder external rotation at BR (p=0.036); and elbow flexion at FC and MER (p=0.018, p=0.044). Trunk kinematic differences may be the result of pitchers throwing from a mound versus flat ground, just as upper extremity kinematic differences could be the result of the weight and shape of the ball.