Inverse dynamics analysis of youth pitching arm kinetics using body composition imaging.

Area of Science:

• Biomechanics
• Sports Medicine
• Pediatric Sports Science

Background:

• Accurate estimation of limb segment masses is crucial for biomechanical analysis of pitching.
• Traditional scaled mass estimations may not fully capture individual variations in youth athletes.
• Understanding the relationship between body composition and pitching kinetics is vital for injury prevention.

Purpose of the Study:

• To evaluate if dual energy X-ray absorptiometry (DXA)-derived segment masses alter inverse dynamics (ID) predictions of youth pitching arm kinetics.
• To examine the correlations between pitching arm kinetics and body composition in young baseball pitchers.

Main Methods:

• Eighteen 10-11-year-old baseball pitchers performed 10 fastballs each.
• Dual energy X-ray absorptiometry (DXA) scans measured participant-specific upper arm, forearm, and hand masses.
• Pitching arm segment masses and kinetics were calculated using both scaled and DXA masses, then compared using paired t-tests and linear regression for correlations.

Main Results:

• DXA masses were significantly different from scaled masses for upper arm (greater), forearm (lesser), and hand (greater) segments.
• Using DXA masses resulted in significantly increased predictions for shoulder compressive force, internal rotation torque, and horizontal adduction torque.
• Shoulder compressive force correlated positively with body mass and body mass index (BMI); elbow varus torque correlated with body mass.

Conclusions:

• Participant-specific mass estimations using DXA alter pitching arm kinetics predictions, potentially enhancing the understanding of youth baseball injury risk factors.
• Pitching arm kinetics are associated with body composition, suggesting that higher total body mass and BMI may elevate the risk of shoulder and elbow injuries in young pitchers.