title: Youth Football Injuries: A Prospective Cohort.
abstract: BACKGROUND
  There are approximately 2.8 million youth football players between the ages of 7 and 14 years in the United States. Rates of injury in this population are poorly described. Recent studies have reported injury rates between 2.3% and 30.4% per season and between 8.5 and 43 per 1000 exposures.
  
  
  OBJECTIVE
  Youth flag football has a lower injury rate than youth tackle football. The concussion rates in flag football are lower than in tackle football.
  
  
  METHODS
  Cohort study; Level of evidence, 3.
  
  
  METHODS
  Three large youth (grades 2-7) football leagues with a total of 3794 players were enrolled. Research personnel partnered with the leagues to provide electronic attendance and injury reporting systems. Researchers had access to deidentified player data and injury information. Injury rates for both the tackle and flag leagues were calculated and compared using Poisson regression with a log link. The probability an injury was severe and an injury resulted in a concussion were modeled using logistic regression. For these 2 responses, best subset model selection was performed, and the model with the minimum Akaike information criterion value was chosen as best. Kaplan-Meier curves were examined to compare time loss due to injury for various subgroups of the population. Finally, time loss was modeled using Cox proportional hazards regression models.
  
  
  RESULTS
  A total of 46,416 exposures and 128 injuries were reported. The mean age at injury was 10.64 years. The hazard ratio for tackle football (compared with flag football) was 0.45 (95% CI, 0.25-0.80;P= .0065). The rate of severe injuries per exposure for tackle football was 1.1 (95% CI, 0.33-3.4;P= .93) times that of the flag league. The rate for concussions in tackle football per exposure was 0.51 (95% CI, 0.16-1.7;P= .27) times that of the flag league.
  
  
  CONCLUSIONS
  Injury is more likely to occur in youth flag football than in youth tackle football. Severe injuries and concussions were not significantly different between leagues. Concussion was more likely to occur during games than during practice. Players in the sixth or seventh grade were more likely to suffer a concussion than were younger players.
authors.affiliation: University of Iowa, Iowa City, Iowa, USA.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Peterson
authors.affiliation: University of Iowa, Iowa City, Iowa, USA.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Kruse
authors.affiliation: University of Iowa, Iowa City, Iowa, USA.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Meester
authors.affiliation: University of Iowa, Iowa City, Iowa, USA.
authors.forename: Tyler S
authors.initials: TS
authors.lastname: Olson
authors.affiliation: University of Iowa, Iowa City, Iowa, USA.
authors.forename: Benjamin N
authors.initials: BN
authors.lastname: Riedle
authors.affiliation: John Peter Smith Health Network, Fort Worth, Texas, USA.
authors.forename: Tyler G
authors.initials: TG
authors.lastname: Slayman
authors.affiliation: University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Todd J
authors.initials: TJ
authors.lastname: Domeyer
authors.affiliation: University of Iowa, Iowa City, Iowa, USA.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Cavanaugh
authors.affiliation: University of Kentucky, Lexington, Kentucky, USA.
authors.forename: M Kyle
authors.initials: MK
authors.lastname: Smoot
keywords: concussion; flag football; youth football; youth sports