title: Collision type and player anticipation affect head impact severity among youth ice hockey players.
abstract: OBJECTIVE
  The objective was to determine how body collision type and player anticipation affected the severity of head impacts sustained by young athletes. For anticipated collisions, we sought to evaluate different body position descriptors during delivery and receipt of body collisions and their effects on head impact severity. We hypothesized that head impact biomechanical features would be more severe in unanticipated collisions and open-ice collisions, compared with anticipated collisions and collisions along the playing boards, respectively.
  
  
  METHODS
  Sixteen ice hockey players (age: 14.0 + or - 0.5 years) wore instrumented helmets from which biomechanical measures (ie, linear acceleration, rotational acceleration, and severity profile) associated with head impacts were computed. Body collisions observed in video footage captured over a 54-game season were evaluated for collision type (open ice versus along the playing boards), level of anticipation (anticipated versus unanticipated), and relative body positioning by using a new tool developed for this purpose.
  
  
  RESULTS
  Open-ice collisions resulted in greater head linear (P = .036) and rotational (P = .003) accelerations, compared with collisions along the playing boards. Anticipated collisions tended to result in less-severe head impacts than unanticipated collisions, especially for medium-intensity impacts (50th to 75th percentiles of severity scores).
  
  
  CONCLUSIONS
  Our data underscore the need to provide players with the necessary technical skills to heighten their awareness of imminent collisions and to mitigate the severity of head impacts in this sport.
authors.affiliation: Sports Medicine Research Laboratory, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. jmihalik@email.unc.edu
authors.forename: Jason P
authors.initials: JP
authors.lastname: Mihalik
authors.forename: J Troy
authors.initials: JT
authors.lastname: Blackburn
authors.forename: Richard M
authors.initials: RM
authors.lastname: Greenwald
authors.forename: Robert C
authors.initials: RC
authors.lastname: Cantu
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Marshall
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Guskiewicz
mesh_terms: D000054:Acceleration; D000293:Adolescent; D004867:Equipment Design; D016489:Head Injuries, Closed / Q000503:physiopathology / Q000517:prevention & control; D006260:Head Protective Devices; D006688:Hockey / Q000293:injuries*; D006801:Humans; D008297:Male; D009568:Nitrendipine; D012399:Rotation; D012720:Severity of Illness Index
chemical_list: D009568:Nitrendipine