Lead and Back Hip Flexion-Extension Excursion: A Biomechanical Analysis in High School Baseball Pitchers

Area of Science:

• Biomechanics of pitching
• Sports medicine
• Kinetic chain analysis

Background:

• Established links between lumbopelvic control and throwing arm kinetics in athletes.
• Limited data on in-pitch hip flexion norms and its effect on throwing mechanics.

Purpose of the Study:

• Establish normative values for lead and back hip flexion in high school pitchers.
• Investigate the relationship between hip flexion-extension excursion and throwing arm kinetics, kinematics, and ball velocity.

Main Methods:

• 3D motion capture of 56 high school pitchers during fastball pitches.
• Calculation of normative hip flexion-excursion values and comparison with professional pitchers.
• Regression analysis to assess the association of hip excursion with ball velocity and arm kinetics.

Main Results:

• High school pitchers exhibited significantly less lead and back hip flexion excursion compared to professional pitchers.
• Lower hip flexion excursion correlated with reduced shoulder and elbow torques/forces.
• Hip flexion excursion was not a strong predictor of ball velocity, but back hip excursion predicted shoulder anterior force.

Conclusions:

• High school pitchers demonstrate reduced hip flexion-extension excursion compared to professionals.
• Hip flexion excursion has a minor role in ball velocity but increased back hip excursion may elevate shoulder anterior force, indicating a potential injury risk.