title: Incidence of concussion in contact sports: a systematic review of the evidence.
abstract: OBJECTIVE
  To estimate incidence of concussion in contact sports.
  
  
  METHODS
  Systematic review of the literature on concussion in contact sports.
  
  
  METHODS
  MEDLINE was searched from 1985-2000. Older articles cited in retrieved articles were also reviewed. Articles meeting the inclusion/exclusion criteria were critically appraised for methodologic quality. The incidence of concussion was recalculated in some cases.
  
  
  RESULTS
  Twenty-three out of 63 identified articles were accepted to estimate the risk of concussion. Overall, ice hockey and rugby have the highest incidence of concussion and soccer has the lowest. Male boxers and female taekwondo participants have the highest frequency of concussion at the recreational level.
  
  
  CONCLUSIONS
  There are few good studies on the incidence of concussion and limited information on the risk of concussion for females in contact sports. Some common methodological problems were also identified in this literature with the hope of improving future studies.
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Canada.
authors.forename: Jae O
authors.initials: JO
authors.lastname: Koh
authors.forename: J David
authors.initials: JD
authors.lastname: Cassidy
authors.forename: E Jane
authors.initials: EJ
authors.lastname: Watkinson
mesh_terms: D001265:Athletic Injuries / Q000453:epidemiology*; D001924:Brain Concussion / Q000453:epidemiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D012107:Research Design / Q000592:standards; D012307:Risk Factors