title: The effect of field condition and shoe type on lower extremity injuries in American Football.
abstract: OBJECTIVE
  Considerable improvement has been made in football field surfaces and types of shoe, yet relatively few epidemiological studies have investigated their roles in the risk of football injuries. This study examined the effects of field surface, surface condition and shoe type on the likelihood of lower extremity football injuries.
  
  
  METHODS
  Deidentified data from 188 players from one division I university football team during the 2007-2010 seasons were analysed. Lower extremity injury rate and rate ratio, along with 95% confidence limits, were calculated by football activity, playing surface condition and shoe type.
  
  
  RESULTS
  A total of 130 lower extremity injuries were sustained, with an overall lower extremity injury rate of 33.5/10 000 athlete-sessions. The lower extremity injury rate was 2.61 times higher when the surface condition was abnormal compared with when the surface condition was normal. During games, the risk for lower extremity injury was 3.34 times higher (95% CI 1.70 to 6.56) on artificial turf compared with natural grass. However, this trend was not statistically significant in practice sessions. Furthermore, neither the number of shoe cleats nor the height of the shoe top was statistically associated with risk of lower extremity injuries.
  
  
  CONCLUSIONS
  Football players who played on artificial turf or when the surface condition was abnormal were susceptible to lower extremity injuries. Evidence from this study suggests that further research into playing surfaces and shoe types may provide fruitful opportunities to reduce injuries to collegiate football players.
authors.affiliation: Department of Industrial Engineering, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Jaclyn Nicole
authors.initials: JN
authors.lastname: Iacovelli
authors.forename: Jingzhen
authors.initials: J
authors.lastname: Yang
authors.forename: Geb
authors.initials: G
authors.lastname: Thomas
authors.forename: Hongqian
authors.initials: H
authors.lastname: Wu
authors.forename: Trisha
authors.initials: T
authors.lastname: Schiltz
authors.forename: Danny T
authors.initials: DT
authors.lastname: Foster
mesh_terms: D016512:Ankle Injuries / Q000453:epidemiology / Q000209:etiology*; D015331:Cohort Studies; D005430:Floors and Floorcoverings / Q000706:statistics & numerical data*; D005538:Football / Q000293:injuries*; D006801:Humans; D015994:Incidence; D007718:Knee Injuries / Q000453:epidemiology / Q000209:etiology*; D008420:Manufactured Materials / Q000706:statistics & numerical data; D006109:Poaceae; D012775:Shoes; D014481:United States / Q000453:epidemiology
keywords: Epidemiology; Injury Prevention; Lower extremity injuries