Abstract
Background:
Major League Baseball (MLB) implemented the pitch clock in 2023 to accelerate game pace. Previous studies examined injury frequency but did not assess recovery duration or account for behavioral adaptations. The purpose of this study was to evaluate associations between pitch clock implementation, recovery duration, and injury distribution.
Hypothesis:
Recovery duration would be longer in the post-clock era, particularly among starters, elbow injuries would comprise a greater proportion of upper extremity injuries, and these associations would persist after accounting for the concurrent increase in fastball velocity.
Study Design:
Retrospective cohort study.
Level of Evidence:
Level 3.
Methods:
The cohort included 1086 upper extremity injuries among 625 unique MLB pitchers from 2021 to 2024, classified as occuring within the pre-clock era (2021-2022; n = 569) or post-clock era (2023-2024; n = 517). Recovery duration was defined as the days from one’s injured list (IL) placement to their return to the active roster. Two-way analysis of variance tested the effects of each era and pitcher role (starter vs reliever). Linear and logistic regression models were adjusted for fastball velocity, with pace examined separately as the exposure mechanism. Sensitivity analyses addressed within-pitcher correlation.
Results:
Recovery duration increased from 48.1 to 54.1 days post-clock (+6.01 days;
P
= 0.02), with starters showing a larger increase (+9.65 days;
P
= 0.01) than relievers (+3.65 days;
P
= 0.26). Elbow injuries rose from 18.6% to 27.5% of the proportion of injuries (odds ratio [OR] = 1.65;
P
P
P
= 0.006). After adjustment for velocity, recovery duration (+6.08 days;
P
= 0.02) and elbow injury distribution (OR = 1.57;
P
= 0.003) remained significant. The recovery association persisted when restricted to each pitcher’s first injury (+6.49 days;
P
= 0.05).
Conclusion:
Pitch clock implementation was associated with approximately 6 days of prolonged recovery and a significantly increased proportion of elbow injuries among upper extremity injuries in MLB pitchers. Neither the concurrent increase in fastball velocity nor a pitcher’s accumulated injury history accounted for these associations, which remained significant in both analyses.
Clinical Relevance:
Rule changes affecting interpitch rest may carry meaningful consequences for pitcher health that warrant consideration alongside pace-of-play objectives.