Professional Pitchers with Higher Combined Joint and Segment Velocities Irrespective of Sequence Order Demonstrate Faster Ball Velocity At The Cost of Increased Throwing Arm Kinetics.

Abstract

Background: Observe how summative maximum joint and segment velocities, dependent and independent of sequence order, may impact ball velocity and throwing arm kinetics in professional pitchers.

Methods: Professional (n=338) pitchers threw 8-12 fastball pitches while evaluated with 3Dmotion capture (480 Hz). Pitches (independent and dependent of sequence order) were classified as 'Overall Fast* or 'Overall Slow' with kinematic and kinetic parameters compared between groups. A regression model for ball velocity dependent on maximum joint and segment velocities was also calculated.

Results: In-sequence pitches with 'Overall Fasf velocity consisted of smaller mass (p<0.001, d=0.9) pitchers that achieved faster ball velocity by on average, 1.6m/s or 3.6 mi/hr (p<0.001, d=1.1). When comparing throwing arm kinetics, the 'Overall Fast' pitches had significantly higher absolute shoulder internal rotation torque (p<0.001, d=1.1), shoulder distractive force (p<0.001, d=1.4), elbow medial force (p=0.014, d=0.7), and elbow flexion torque (p<0.001, d=0.7). A multi-regression prediction model for ball velocity based on maximum joint and segment velocities achieved a R²=0.132. Maximum lead knee extension velocity (B: 0.004 0:0.263 p<0.001) and maximum trunk rotation velocity (B: 0.003 0: 0.223 p=0.045) achieved the highest standardized regression coefficients. For every one standard deviation increase in maximum lead knee extension velocity (125 °/sec), ball velocity increased by 0.5 m/s (1.1 MPH).

Conclusion: Professional pitchers with increasing summative maximum joint and segment velocities demonstrated faster ball velocity at the cost of increased throwing arm kinetics, irrespective of sequence order.

Level of evidence: IV.