title: Risks associated with significant head impact events in elite rugby union.
abstract: To conduct video and statistical analysis on Rugby Union play, focusing mainly on the tackle, to establish the player to player configurations for significant direct head impacts and non-direct head impacts.
  
  
  
  Quantitative, observational cohort study.
  
  
  
  Video analysis of 52 significant direct head impacts (31 Tackle, 10 Ruck, 7 Dive and 4 Ground) and 40 non-direct head impact tackles from 2014/15 International Rugby Union matches. Relative risk, 95% CI and p-values were calculated for a range of tackle variables.
  
  
  
  Upper body tackles and lower body tackles accounted for 37% (19) and 23% (12) of cases, respectively, with the tackler as the head impacted player for 97% (30) of cases. The majority (81%) of tackle-related significant direct head impacts occurred in the second half of the game, with 63% of upper body tackle significant direct head impacts occurring in the final quarter. Tackler head placement and high speed tackles had statistical significance for causing tackle related significant direct head impacts as well as foot planting and difference in tackler and ball carrier mass for upper body tackles and ball carrier change in direction for lower body tackles.
  
  
  
  Tackle variables that statistically increased the risk of significant direct head impact were identified, which can aid player protection strategies.
authors.affiliation: a Trinity Centre for Bioengineering , Trinity College Dublin , Ireland.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Tierney
authors.affiliation: a Trinity Centre for Bioengineering , Trinity College Dublin , Ireland.
authors.forename: John
authors.initials: J
authors.lastname: Lawler
authors.affiliation: b Leinster Rugby , Dublin , Ireland.
authors.forename: Karl
authors.initials: K
authors.lastname: Denvir
authors.affiliation: b Leinster Rugby , Dublin , Ireland.
authors.forename: Kurt
authors.initials: K
authors.lastname: McQuilkin
authors.affiliation: a Trinity Centre for Bioengineering , Trinity College Dublin , Ireland.
authors.forename: Ciaran K
authors.initials: CK
authors.lastname: Simms
mesh_terms: D000328:Adult; D001265:Athletic Injuries / Q000150:complications* / Q000453:epidemiology*; D015331:Cohort Studies; D006259:Craniocerebral Trauma / Q000175:diagnosis / Q000209:etiology*; D005538:Football / Q000293:injuries* / Q000502:physiology; D006801:Humans; D008297:Male; D018570:Risk Assessment; D012307:Risk Factors; D014741:Video Recording
keywords: Sport; statistical analysis; video analysis