Comparison of Elbow Flexion in Youth Baseball Pitchers With and Without Throwing-Arm Pain

Abstract

Background: More than half of all youth baseball pitchers report throwing-related pain in their throwing arm throughout a season.

Purpose/hypothesis: The purpose of this study was to investigate differences in elbow flexion throughout the pitching cycle between youth baseball pitchers with and without throwing-arm pain. It was hypothesized that pitchers with throwing-arm pain would have decreased elbow flexion throughout the pitching cycle compared with those who were pain-free.

Study design: Controlled laboratory study.

Methods: A total of 38 youth baseball pitchers (mean age, 13.3 ± 1.7 years; height, 164.4 ± 12.9 cm; weight, 57.1 ± 14 kg) were retrospectively selected from a database. Based on responses to a health history questionnaire, the pitchers were placed into a pain group if they indicated they were experiencing throwing-arm pain. Pitchers who indicated they were not experiencing throwing-arm pain were matched according to age, height, and weight to the pain group. All pitchers threw 3 fastballs to a catcher at the regulation distance. The mean elbow flexion of the 3 trials was used during analysis to investigate peak elbow flexion and time-normalized (0%-100%) elbow flexion across the pitch cycle (stride-foot contact to ball release). Elbow flexion was compared between the pain and pain-free groups using 1-dimensional statistical nonparametric mapping, and the mean peak elbow flexion between groups was compared using the Mann-Whitney U test.

Results: No significant differences were observed between the groups in elbow flexion throughout the pitching cycle (P > .05) and no group differences in peak elbow flexion (U = 122; P = .09).

Conclusion: Study findings indicated no significant differences in elbow flexion between youth baseball pitchers with versus without throwing-arm pain, unlike previous research reporting that pitchers with a history of medial elbow pain had altered elbow flexion and higher pitch velocities compared with those without a history of pain.

Clinical relevance: Clinicians should consider other potential factors related to throwing-arm pain beyond elbow flexion. Moreover, it is advisable to focus on evidence-based modifiable factors shown to increase the risk of pain and injury in youth pitchers, such as exceeding pitch counts, number of innings pitched, increased training time, range-of-motion, and strength deficits.

Keywords: biomechanics; injury prevention; statistical parametric mapping.