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Sliding-Associated Injuries in College and Professional Baseball -- 1990-1991

Softball and baseball are among the most frequent causes of sports-related emergency department visits in the United States, accounting for an estimated 321,000 injuries in 1989 (1). Approximately 71% of softball-related injuries are caused by sliding (2). The use of breakaway bases substantially decreases the risk for or occurrence of sliding-related injuries among recreational softball league players (3). This report summarizes the findings of a study on the impact of breakaway base use on sliding injuries among college and professional minor league baseball players (4).

During 1990 and 1991, 19 teams participating in the study used breakaway bases on their home field and stationary bases during away games for one of the two seasons. During the first season, the teams comprised one college and six professional minor league teams; during the second season, seven college and five minor league teams were added to the study. Base-sliding injuries and comments about the bases were recorded on a standard form by team physicians, athletic trainers, managers, or administrative staff for these teams.

During the 2-season period, the teams played an aggregate 498 away games using stationary bases and 486 home games using breakaway bases. Ten sliding injuries were recorded (2.0 per 100 games) during away games and two (0.4 per 100 games) during home games (relative risk=4.9; 95% confidence interval=1.2-19.2). Of the 10 injuries involving stationary bases, seven were ankle sprains (average participation time missed: 12 days), and three were knee injuries (one medial collateral ligament sprain and two meniscus tears that required surgery {both were season-ending}). Of the two injuries involving breakaway bases, one was a minor shoulder contusion incurred when the player slid head first into a base that did not release. The second injury occurred when a player slid toward the base and sustained an ankle fracture; however, the player did not make contact with the base.

Surveys of managers and trainers indicated that all teams planned to continue using breakaway bases. Umpires reported that breakaway bases did not complicate judgment calls (i.e., "safe" versus "out") when the bases released (54 {2.7%} of 2028 total slides on breakaway bases).

Reported by: DH Janda, MD, D Mackesy, MD, Institute for Preventive Sports Medicine, Ann Arbor, Michigan. R Maguire, Bucknell Univ, Lewisburg, Pennsylvania. RJ Hawkins, MD, Steadman-Hawkins Clinic, Vail, Colorado. P Fowler, MD, Univ of Western Ontario, London, Ontario, Canada. J Boyd, MD, Orthopaedic Consultants, Minneapolis. Epidemiology Br, Div of Injury Control, National Center for Injury Prevention and Control, CDC.

Editorial Note

Editorial Note: The findings in this report suggest that breakaway bases decrease the risk and severity of sliding injuries among college and minor league baseball teams (4). The potential public health impact of increased use of breakaway bases is important: in the United States, 712 college and 168 minor league teams compete in organized baseball. In addition, an estimated 40 million adults participate in organized softball leagues that play approximately 23 million games per year (3,5).

Most base-sliding injuries result from judgment errors of the runners, poor sliding technique, poor timing, and/or inadequate physical conditioning (3). Breakaway bases are a passive intervention that modifies the outcome of these factors. The quick-release feature of the breakaway bases decreases the impact load generated against the athlete's limb and subsequent trauma. Additional studies should assess the usefulness of age-appropriate breakaway bases in organized baseball and softball for children. Furthermore, such studies should attempt to address the effect of potential biases (e.g., nonblinding with respect to the hypothesis being tested and the need for uniform definitions of injury). The findings in this report suggest that breakaway bases should be used at all levels of adult softball and baseball play.


  1. US Consumer Product Safety Commission. National Electronic Injury Surveillance System: January-December 1989. NEISS Data Highlights 1990;13.

  2. Janda DH, Hankin FM, Wojtys EM. Softball injuries: cost, cause and prevention. Am Fam Physician 1986;33:143-4.

  3. Janda DH, Wojtys EM, Hankin FM, et al. Softball sliding injuries: a prospective study comparing standard and modified bases. JAMA 1988;259:1848-50.

  4. Janda DH, Maguire R, Mackesy D, Hawkins RJ, Fowler P, Boyd J. Sliding injuries in college and professional baseball: a prospective study comparing standard and break-away bases. Clinical Journal of Sports Medicine (in press).

  5. CDC. Softball sliding injuries -- Michigan, 1986-1987. MMWR 1988;37:169-70.

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