title: Similar head impact acceleration measured using instrumented ear patches in a junior rugby union team during matches in comparison with other sports.
abstract: OBJECTIVE Direct impact with the head and the inertial loading of the head have been postulated as major mechanisms of head-related injuries, such as concussion. METHODS This descriptive observational study was conducted to quantify the head impact acceleration characteristics in under-9-year-old junior rugby union players in New Zealand. The impact magnitude, frequency, and location were collected with a wireless head impact sensor that was worn by 14 junior rugby players who participated in 4 matches. RESULTS A total of 721 impacts > 10g were recorded. The median (interquartile range [IQR]) number of impacts per player was 46 (IQR 37-58), resulting in 10 (IQR 4-18) impacts to the head per player per match. The median impact magnitudes recorded were 15g (IQR 12g-21g) for linear acceleration and 2296 rad/sec(2) (IQR 1352-4152 rad/sec(2)) for rotational acceleration. CONCLUSIONS There were 121 impacts (16.8%) above the rotational injury risk limit and 1 (0.1%) impact above the linear injury risk limit. The acceleration magnitude and number of head impacts in junior rugby union players were higher than those previously reported in similar age-group sports participants. The median linear acceleration for the under-9-year-old rugby players were similar to 7- to 8-year-old American football players, but lower than 9- to 12-year-old youth American football players. The median rotational accelerations measured were higher than the median and 95th percentiles in youth, high school, and collegiate American football players.
authors.affiliation: Sports Performance Research Institute New Zealand, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand;
authors.forename: Doug A
authors.initials: DA
authors.lastname: King
authors.affiliation: Sports Performance Research Institute New Zealand, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand;
authors.forename: Patria A
authors.initials: PA
authors.lastname: Hume
authors.affiliation: School of Sport, Health and Applied Science, St Mary's University, Twickenham, Middlesex, United Kingdom and.
authors.forename: Conor
authors.initials: C
authors.lastname: Gissane
authors.affiliation: Australian College of Physical Education, Faculty of Sport Performance, Sydney Olympic Park, New South Wales, Australia.
authors.forename: Trevor N
authors.initials: TN
authors.lastname: Clark
mesh_terms: D000054:Acceleration; D061725:Accelerometry / Q000295:instrumentation* / Q000379:methods; D002648:Child; D015331:Cohort Studies; D006259:Craniocerebral Trauma / Q000175:diagnosis / Q000517:prevention & control; D004423:Ear; D005538:Football / Q000293:injuries* / Q000502:physiology; D006260:Head Protective Devices; D006801:Humans; D011446:Prospective Studies
keywords: HITS = Head Impact Telemetry System; IQR = interquartile range; K-D = King-Devick; PLA = peak linear acceleration; PRA = peak rotational acceleration; impact; injury; linear; rotational; rugby union; trauma; wireless head impact sensor