Comparison of Trunk and Pelvic Kinematics in Youth Baseball Pitchers With and Without Upper Extremity Pain: A Cross-Sectional Study.

Background: Motion of the pelvis and trunk during baseball pitching is associated with increased upper extremity (UE) kinetics. Increased kinetics on the UE may lead to throwing-arm pain in youth pitchers. Limited biomechanical comparisons have been conducted on youth pitchers with and without throwing-arm pain to identify mechanical risk factors associated with pain.

Purpose: To examine trunk and pelvic kinematics in youth baseball pitchers with and without UE pain.

Study Design: Cross-sectional study; Level of evidence, 3.

Methods: A total of 26 male youth baseball pitchers (mean age, 12.7 ± 1.5 years; mean height, 162.2 ± 12.9 cm; mean weight, 52.6 ± 13.1 kg) were recruited to participate. An electromagnetic tracking system was used to obtain kinematic data during the fastball pitch. Data from a health history questionnaire was examined. Participants who answered "yes" to experiencing pain and who selected a region on their UE as the pain location were placed into the UE pain group. Participants who responded "no" to experiencing pain were placed into the pain-free group. We compared between-group differences in trunk rotation, flexion, and lateral flexion; pelvic rotation, anteroposterior tilt, and lateral tilt; and hip-shoulder separation from peak knee height to ball release of the baseball pitch using 1-dimensional statistical parametric mapping with an alpha level set at .05.

Results: No statistically significant differences were observed between the UE pain and pain-free groups in the 7 trunk and pelvic kinematics analyzed from peak knee height to ball release ( > .05).

Conclusion: Trunk and pelvic kinematics during the pitching motion did not differ between pain and pain-free groups of youth baseball pitchers.