Head impacts in a junior rugby league team measured with a wireless head impact sensor: an exploratory analysis

Abstract

<jats:sec> <jats:title>OBJECTIVE</jats:title> <jats:p>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.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>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).</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>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 10<jats:italic>g</jats:italic> to 123<jats:italic>g</jats:italic> (mean 22<jats:italic>g</jats:italic>, median 16<jats:italic>g</jats:italic>, and 95th percentile 57<jats:italic>g</jats:italic>). The rotational acceleration ranged from 89 rad/sec<jats:sup>2</jats:sup> to 22,928 rad/sec<jats:sup>2</jats:sup> (mean 4041 rad/sec<jats:sup>2</jats:sup>, median 2773 rad/sec<jats:sup>2</jats:sup>, and 95th percentile 11,384 rad/sec<jats:sup>2</jats:sup>).</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>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.</jats:p></jats:sec>

Head impact exposure comparison between male and female amateur rugby league participants measured with an instrumented patch

“…Impacts to the side of the head were commonly reported in male (n=1,762; 42%) and female (n= 791; 48%) amateur rugby league participants. This is similar to junior [26] and amateur senior [21] rugby union and junior [22] rugby league. The impact side differed in each of the comparison studies with males recording impacts to the front [8], side [18] and back [25] of the head while females recorded impacts to the side [8] and back [18,25] of the head.…”

“…To better understand concussive injuries, head impact biomechanics have been extensively studied in a variety of sporting environments such as American football [11][12][13][14], soccer [15,16], ice hockey [17,18], lacrosse [19], Australian rules football [20], rugby union [21] and rugby league [22][23][24]. The studies reporting on head impact biomechanics in rugby league have been undertaken at junior [22], senior amateur male [23] and senior amateur female [24], levels of participation. It has been reported that junior rugby league players [22] recorded a mean of 13 impacts per-player permatch, resulting in a median PLA(g) and PRA(rad/s 2 ) of 16g and 2,773 rad/s 2 .…”

“…The studies reporting on head impact biomechanics in rugby league have been undertaken at junior [22], senior amateur male [23] and senior amateur female [24], levels of participation. It has been reported that junior rugby league players [22] recorded a mean of 13 impacts per-player permatch, resulting in a median PLA(g) and PRA(rad/s 2 ) of 16g and 2,773 rad/s 2 . This was similar for senior female amateur rugby league players [24] with a mean of 14 impacts per-player per-match resulting in median PLA(g) and PRA(rad/s 2 ) of 15g and 2,886 rad/s 2 .…”

“…Although these studies [22][23][24] identi ied the magnitude, frequency and location of impacts to the head, only a few studies [11,18,19,25], have compared male and female head impact biomechanics within the same sporting activity. All these studies [11,18,19,25] reported that males recorded more impacts to the head in both match and practice sessions when compared with females.…”

“…Rugby league and rugby union are two sporting codes where the rules and regulations are identical for both male and female participants. Although studies [21][22][23][24]26] have been published in both these sporting codes, only rugby league have reported on male [23] and female [24] impacts to the head at the same level of participation. Previous studies [11,18,19,25] have reported comparisons between male and female participants where gender speci ic rules applied.…”