Do Pitching Restriction Policies Reduce Shoulder and Elbow Injuries in High School Baseball Players?

Background: Shoulder and elbow injuries (SEIs) remain prevalent among high school (HS) baseball players. Pitching restriction (PR) policies were mandated by the National Federation of State High School Associations (NFHS) in 2016 as an injury prevention strategy to set workload limits and reduce overuse injuries. The effect of PR policies on HS baseball SEIs remains unknown. Hypotheses: (1) SEI rates in HS baseball players would be lower in the 3 seasons after PR policy implementation when compared with the 3 seasons before PR policy implementation and (2) specific components of PR policies would be associated with statistically significant decreases in SEI rates. Study Design: Descriptive epidemiological study. Methods: NFHS member state PR policies were obtained from publicly available websites, and components of each policy were analyzed for similarities and differences. SEI/exposure data for US HS baseball players were obtained from High School Reporting Information Online, a sports injury surveillance system. Athletic trainers reported practice and competition injury and athlete-exposure (AE) data from a national school sample during the 2013-2014 through 2018-2019 academic years. Results: During the study period, 295 (164 shoulder, 131 elbow) injuries occurred during 1,554,708 AEs. No statistically significant changes were found in SEI rates, shoulder-specific rates, or elbow-specific injury rates after PR policy mandates were implemented. When analyzing injury rates for practices and competitions collectively, consecutive pitching day rest rules (incidence rate ratio [IRR], 0.32; 95% CI, 0.22-0.46), ≤105 pitch daily maximum (IRR, 0.40; 95% CI, 0.31-0.51), different PR policy rules for regular versus postseason (IRR, 0.43; 95% CI, 0.27-0.65), varsity versus subvarsity pitch count maximums (IRR, 0.46; 95% CI, 0.35-0.59), and ≥4 days' rest if >105 pitch count (IRR, 0.53; 95% CI, 0.42-0.68) provided protective effects against SEIs compared with PR policies without these components. Conclusion: Specific components of PR policies rather than a national PR policy mandate were associated with significant reduction in SEI rates in HS baseball players. The presence of a consecutive pitching day rest rule and daily maximum pitch count of ≤105 pitches were associated with significant reductions in SEIs based on total (practice and competition) exposures, practice exposures, and competition exposures.