Slider Horizontal Movement and Arm Angle are Associated with Elbow and Forearm Injury Incidence in MLB Pitchers
- 1University of California, San Diego
Abstract
BackgroundSweeping sliders with large horizontal break are hypothesized to be associated with arm injury, and prior work suggests a link between slider usage, arm angle, and injury.
PurposeTo evaluate whether arm angle and slider horizontal movement are associated with elbow or forearm injury risk in MLB pitchers.
Study DesignRetrospective cohort study; Level of evidence, 3
MethodsStatcast data from 2020-2025 and injury data were used to study the relationship between sliders and arm injuries. Pitchers with at least 30 innings pitched (IP) were evaluated for same- and next-season injury incidence to the Elbow, Forearm, or Elbow/Forearm. A generalized additive model (GAM) related pitch-level variables to injury incidence, and average marginal effect (AME) odds ratios are reported for main effects.
ResultsAll fits were significant at p < .01. Fits for same-season (N = 1,957, p = .00008, R2 = .066) and next-season (N = 2,511, p = .00005, R2 = .053) Elbow/Forearm injury were significant at p < .001. Same-season (R2 = .061) and next-season (R2 = .055) Forearm injury fits had p = .001. Main effects for slider glove-side movement and fastball usage, their interactions with arm angle, and arm angle main effects were the most predictive features. Across the three fits where the slider glove-side movement main effect was significant, odds ratios ranged from 1.03 to 1.07, meaning that each additional inch of slider glove-side movement was associated with a 3% to 7% increase in the observed injury incidence. Furthermore, this effect was magnified at high arm angle and muted at low arm angle.
ConclusionWe observed that slider horizontal movement, arm angle, and their interaction were significantly associated with incidence of Forearm and combined Elbow/Forearm injury. This effect was weak or non-existent at low arm angles and strong at high arm angles, suggesting that arm angle moderates the risk of slider horizontal movement, and providing evidence that sliders with large horizontal break (e.g. sweepers) may pose an injury risk.
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BibTeX
@misc{richards2026slider,
title = {{Slider Horizontal Movement and Arm Angle are Associated with Elbow and Forearm Injury Incidence in MLB Pitchers}},
author = {C. Richards and D. T. La Salle and O. Vila Dieguez and S. R. Ward},
howpublished = {medRxiv},
year = {2026},
month = aug,
doi = {10.64898/2026.08.30.26361739},
url = {https://www.medrxiv.org/content/10.64898/2026.08.30.26361739v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Slider Horizontal Movement and Arm Angle are Associated with Elbow and Forearm Injury Incidence in MLB Pitchers
AU - C. Richards
AU - D. T. La Salle
AU - O. Vila Dieguez
AU - S. R. Ward
PY - 2026
DA - 2026/08/30
PB - medRxiv
DO - 10.64898/2026.08.30.26361739
UR - https://www.medrxiv.org/content/10.64898/2026.08.30.26361739v1
AB - BackgroundSweeping sliders with large horizontal break are hypothesized to be associated with arm injury, and prior work suggests a link between slider usage, arm angle, and injury. PurposeTo evaluate whether arm angle and slider horizontal movement are associated with elbow or forearm injury risk in MLB pitchers. Study DesignRetrospective cohort study; Level of evidence, 3 MethodsStatcast data from 2020-2025 and injury data were used to study the relationship between sliders and arm injuries. Pitchers with at least 30 innings pitched (IP) were evaluated for same- and next-season injury incidence to the Elbow, Forearm, or Elbow/Forearm. A generalized additive model (GAM) related pitch-level variables to injury incidence, and average marginal effect (AME) odds ratios are reported for main effects. ResultsAll fits were significant at p < .01. Fits for same-season (N = 1,957, p = .00008, R2 = .066) and next-season (N = 2,511, p = .00005, R2 = .053) Elbow/Forearm injury were significant at p < .001. Same-season (R2 = .061) and next-season (R2 = .055) Forearm injury fits had p = .001. Main effects for slider glove-side movement and fastball usage, their interactions with arm angle, and arm angle main effects were the most predictive features. Across the three fits where the slider glove-side movement main effect was significant, odds ratios ranged from 1.03 to 1.07, meaning that each additional inch of slider glove-side movement was associated with a 3% to 7% increase in the observed injury incidence. Furthermore, this effect was magnified at high arm angle and muted at low arm angle. ConclusionWe observed that slider horizontal movement, arm angle, and their interaction were significantly associated with incidence of Forearm and combined Elbow/Forearm injury. This effect was weak or non-existent at low arm angles and strong at high arm angles, suggesting that arm angle moderates the risk of slider horizontal movement, and providing evidence that sliders with large horizontal break (e.g. sweepers) may pose an injury risk.
ER -