title: Head impacts in a junior rugby league team measured with a wireless head impact sensor: an exploratory analysis.
abstract: OBJECTIVE The aim of this study was to investigate the frequency, magnitude, and distribution of head impacts sustained by players in a junior rugby league over a season of matches. METHODS The authors performed a prospective cohort analysis of impact magnitude, frequency, and distribution on data collected with instrumented XPatches worn behind the ear of players in an "under-11" junior rugby league team (players under 11 years old). RESULTS A total of 1977 impacts were recorded. Over the course of the study, players sustained an average of 116 impacts (average of 13 impacts per player per match). The measured linear acceleration ranged from 10g to 123g (mean 22g, median 16g, and 95th percentile 57g). The rotational acceleration ranged from 89 rad/sec2to 22,928 rad/sec2(mean 4041 rad/sec2, median 2773 rad/sec2, and 95th percentile 11,384 rad/sec2). CONCLUSIONS The level of impact severity based on the magnitude of impacts for linear and rotational accelerations recorded was similar to the impacts reported in studies of American junior and high school football, collegiate football, and youth ice hockey players, but the players in the rugby league cohort were younger, had less body mass, and played at a slower speed than the American players. Junior rugby league players are required to tackle the player to the ground and use a different tackle technique than that used in American football, likely increasing the rotational accelerations recorded at the head.
authors: Sports Performance Research Institute New Zealand, Faculty of Health and Environmental Science, Auckland University of Technology, Auckland, New Zealand.
authors: Doug
authors: D
authors: King
authors: Sports Performance Research Institute New Zealand, Faculty of Health and Environmental Science, Auckland University of Technology, Auckland, New Zealand.
authors: Patria
authors: P
authors: Hume
authors: School of Sport Health and Applied Science, St Mary's University, Twickenham, Middlesex, United Kingdom; and.
authors: Conor
authors: C
authors: Gissane
authors: Australian College of Physical Education, Faculty of Sport Performance, Sydney Olympic Park, New South Wales, Australia.
authors: Trevor
authors: T
authors: Clark
mesh_terms: D000054:Acceleration; D061725:Accelerometry / Q000295:instrumentation* / Q000379:methods; D001924:Brain Concussion / Q000175:diagnosis* / Q000209:etiology; D002648:Child; D015331:Cohort Studies; D005260:Female; D005538:Football / Q000293:injuries* / Q000502:physiology; D006260:Head Protective Devices; D006801:Humans; D008297:Male; D011446:Prospective Studies
keywords: HITS = Head Impact Telemetry System; HITSP = Head Impact Telemetry severity profile; ICC = intraclass correlation coefficient; ImPACT = Immediate Postconcussion Assessment Cognitive Test; K-D = King-Devick; NFL = National Football League; PLA = peak linear acceleration; PRA peak rotational acceleration; RWECP = risk weighted exposure based on combined probability; impact; injury; linear; rotational; rugby union; trauma; wireless head impact sensor