title: Abdominal muscle strains in professional baseball: 1991-2010.
abstract: BACKGROUND
  The abdominal core muscles (internal and external oblique, rectus and transversus abdominis) play an important role in the baseball activities of pitching and hitting. Proper abdominal muscle activation during throwing and swinging is crucial for generating optimal ball velocity and bat speed. Abdominal muscle strains can result in substantial loss of playing time, and their incidence has never been reported in baseball.
  
  
  OBJECTIVE
  The incidence of abdominal muscle strains in Major League Baseball has been rising over the past 20 years. Injuries contralateral to the dominant arm or batting side are more common and require more time to recover.
  
  
  METHODS
  Descriptive epidemiology study.
  
  
  METHODS
  Abdominal muscle strains in baseball players were determined by retrospective review of the Major League Baseball disabled list from 1991 to 2010. Player age, position, dominant hand, batting side, and recovery time were recorded.
  
  
  RESULTS
  There were 393 abdominal muscle strains in Major League Baseball from 1991 to 2010, constituting 5% of all baseball injuries. At least 92% of these injuries were internal/external oblique or intercostal muscle strains, and 44% of injuries were sustained by pitchers. The reinjury rate was 12.1%. An upward trend was seen from 1991 to 2010, especially in early-season injuries, and the overall injury rate was 22% higher in the 2000s than in the 1990s. Pitchers averaged 35.4 days on the disabled list compared with 26.7 days for position players (P < .01); 78.1% of pitcher injuries were contralateral to their dominant arm, and 70.3% of position player injuries were contralateral to their dominant batting side (excluding switch hitters). Position players missed more time for contralateral than for ipsilateral injuries (28.9 vs 21.2 days, P = .03), whereas pitchers missed more time for ipsilateral injuries (44.5 vs 32.8 days, P = .04).
  
  
  CONCLUSIONS
  The incidence of abdominal muscle strains in baseball has been increasing over the past 20 years, especially early in the season, and there is a relatively high reinjury rate. This upward trend is in spite of new and more advanced diagnostic procedures, preventive core strengthening exercise programs, and rehabilitation techniques. Injuries contralateral to the dominant arm or batting side are more common.
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
authors.forename: Stan A
authors.initials: SA
authors.lastname: Conte
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Thompson
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Marks
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Dines
mesh_terms: D000009:Abdominal Muscles / Q000293:injuries*; D000328:Adult; D001484:Baseball / Q000293:injuries*; D006801:Humans; D015994:Incidence; D008297:Male; D012189:Retrospective Studies; D013180:Sprains and Strains / Q000453:epidemiology* / Q000517:prevention & control / Q000534:rehabilitation