title: Foul play is associated with injury incidence: an epidemiological study of three FIFA World Cups (2002-2010).
abstract: BACKGROUND
  Foul play has been considered as one of the most important known extrinsic risk factors for injuries in football.
  
  
  OBJECTIVE
  To compare the incidence and characteristics of foul play injuries and non-foul injuries.
  
  
  METHODS
  Team physicians' postmatch injury reports and official match statistics were obtained from all matches of the 2002, 2006 and 2010 Fédération Internationale de Football Association World Cups.
  
  
  RESULTS
  The number of injuries was associated with the number of fouls in a match. The incidence of foul play injuries (20.6/1000 match-hours, 95% CI 17.3 to 24.4) was significantly lower than that of non-foul injuries (42.6, 37.7 to 47.9), which also applied to all playing positions. The causation of injury (foul/non-foul), match period and teams' drawing/losing/winning status were associated with the injury incidence. The interactions between the causation of injury (foul/non-foul) and match time, as well as the teams' drawing/losing/winning status or playing position were not statistically significant. The median (IQR) days of absence resulting from foul play injuries were significantly shorter than that of non-foul injuries. The lower leg and ankle were more common locations for foul play injuries than for non-foul injuries, whereas the opposite was observed for thigh injuries. Contusions were a more common type of foul play injuries than non-foul injuries, while the opposite was found for muscle strains/ruptures/tears.
  
  
  CONCLUSIONS
  The numbers of injuries and fouls in a match were significantly associated. No significant differences in the variation of foul play and non-foul injury incidences regarding match period, teams' current winning/drawing/losing status and playing position were observed, suggesting that foul play injuries and non-foul injuries may share similar underlying risk factors.
authors.affiliation: Faculty of Medicine, University of Helsinki, , Helsinki, Finland.
authors.forename: Jaakko
authors.initials: J
authors.lastname: Ryynänen
authors.forename: Astrid
authors.initials: A
authors.lastname: Junge
authors.forename: Jiri
authors.initials: J
authors.lastname: Dvorak
authors.forename: Lars
authors.initials: L
authors.lastname: Peterson
authors.forename: Hannu
authors.initials: H
authors.lastname: Kautiainen
authors.forename: Jón
authors.initials: J
authors.lastname: Karlsson
authors.forename: Mats
authors.initials: M
authors.lastname: Börjesson
mesh_terms: D001265:Athletic Injuries / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D015994:Incidence; D009141:Musculoskeletal System / Q000293:injuries; D012189:Retrospective Studies; D012307:Risk Factors; D012916:Soccer / Q000293:injuries* / Q000706:statistics & numerical data; D013997:Time Factors
keywords: Epidemiology; Soccer; Sporting Injuries