DOI
https://doi.org/10.25772/44XF-ZX03
Defense Date
2025
Document Type
Thesis
Degree Name
Master of Science
Department
Biomedical Engineering
First Advisor
Carrie L. Peterson
Abstract
Introduction Baseball pitching imposes substantial mechanical demands on the lumbar spine, a crucial link in the kinetic chain responsible for transferring energy from the lower body to the upper extremity. While increased pitch velocity is associated with greater trunk forces the specific intervertebral loading patterns during high-velocity pitching remain unclear. This study investigates differences in lateral bending moments across lumbar spinal segments between collegiate pitchers throwing at high versus low velocities.
Methods Twenty right-handed collegiate pitchers were divided into two groups: high-velocity (n = 10, 90.3 ± 1.6 mph) and low-velocity (n = 10, 81.6 ± 1.1 mph). Motion capture and external ground reaction forces from an open-access pitching dataset were processed using OpenSim. A thoracolumbar model and inverse dynamics analysis was used to compute lateral bending moments at six intervertebral joints (T12/L1 to L5/S1). Statistical parametric mapping (SPM) was used to compare moment waveforms between groups across a time-normalized window centered around maximum shoulder external rotation.
Results SPM analysis revealed significant group differences at L5/S1 (p = 0.014) and L3/L4 (p = 0.009), with high-velocity pitchers showing average peak moments approximately 28% higher at L5/S1, and 24% higher at L3/L4. Additionally, the T12/L1 segment showed multiple significant intervals (p = 0.025–0.016) of increased loading in the fast group. These peaks occurred primarily during late cocking and early acceleration, consistent with the proposed high trunk demands during segmental separation and force transfer.
Conclusions These findings confirm that high-velocity pitchers experience
greater and more temporally concentrated lateral bending loads at key lumbar and thoracolumbar junctions. This suggests that enhanced spinal engagement plays a role in generating higher throwing speeds. From a performance standpoint, these insights highlight the importance of trunk control and spinal stability in energy transfer. From an injury prevention perspective, the increased and localized loading observed in high-velocity throwers emphasizes the need for targeted strength, mobility, and recovery strategies to mitigate the risk of overuse injuries to the lumbar spine.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
8-7-2025