Exceeding Pitch Count Recommendations In Youth Baseball Increases The Elbow Injuries
Authors: Matsuura Tetsuya , Iwame Toshiyuki , Sairyo Koichi 
Published: July 2018

Objectives: With the incidence of Little League elbow increasing, pitch limit recommendations for preventing throwing injuries have been developed in the United States and Japan. In 1995, the Japanese Society of Clinical Sports Medicine announced limits of 50 pitches per day and 200 pitches per week to prevent throwing injuries in younger than 12 years old. However the relationship between pitch limit recommendation and elbow injuries among pitchers has not been adequately studied. The aim of our study was to evaluate the association between pitch counts and elbow injuries in youth pitchers. Methods: A total of 149 pitchers without prior elbow pain were observed prospectively for 1 season to study injury incidence in relation to specific risk factors. Average age was 10.1 years (range, 7-11 years). One year later, all pitchers were examined by questionnaire. Subjects were asked whether they had experienced any episodes of elbow pain during the season. The questionnaire was also used to gather data on pitch counts per day and per week, age, number of training days per week, and number of games per year. We investigated the following risk factors for elbow injury: pitch counts, age, position, number of training days per week, and number of games per year. Data were analyzed by multivariate logistic regression models and presented as odds ratio (OR) and profile likelihood 95% confidence interval (CI) values. The likelihood-ratio test was also performed. A two-tailed P value of less than .05 was considered significant. All analysis was done in the SAS software package (version 8.2). Results: Of the 149 subjects, 66 (44.3%) reported episodes of pain in the throwing elbow during the season. 1. Analysis for pitch count per day Univariate analysis showed that elbow pain was significantly associated with more than 50 pitches per day. Multivariate analysis showed that more than 50 pitches per day (OR, 2.44; 95% CI, 1.22-4.94), and more than 70 games per year (OR, 2.47; 95% CI, 1.24-5.02) were risk factors significantly associated with elbow pain. Age and number of training days per week were not significantly associated with elbow pain. 1. Analysis for pitch count per week Univariate analysis showed that elbow pain was significantly associated with more than 200 pitches per week. Multivariate analysis showed that more than 200 pitches per week (OR, 2.04; 95% CI, 1.03-4.10), and more than 70 games per year (OR, 2.41; 95% CI, 1.22-4.87) were risk factors significantly associated with elbow pain. Age was not significantly associated with elbow pain. Conclusion: A total of 44.3% of youth baseball pitchers had elbow pain during the season. Multivariable logistic regression revealed that elbow pain was associated with more than 50 pitches per day, more than 200 pitches per week, and more than 70 games per year. Previous studies have revealed the risk factor with the strongest association to injury is pitcher. Our data suggest that compliance with pitch limit recommendations including limits of 50 pitches per day and 200 pitches per week may be protective against elbow injuries. Those who played more than 70 games per year had a notably increased risk of injury. With increasing demand on youth pitchers to play more, there is less time for repair of bony and soft tissues in the elbow. In conclusion, among youth pitchers, limits of 50 pitches per day, 200 pitches per week, and limits of 70 games per year may protect elbow injuries.