Abstract
Background: Mild traumatic brain injuries (TBIs) account for 73% of elite snow sports head/face injuries, 82% of which are categorised as concussions. The addition of park and pipe disciplines (Big Air, Slopestyle, and Halfpipe) to the Olympic Winter Games has progressively increased trick complexity, increasing the already high risk of mild traumatic brain injuries (TBIs). The significant rotational forces in these disciplines are of particular interest as they can increase the risk of brain injury. Wearable sensors, such as instrumented mouthguards (iMG), can accurately and non-invasively monitor head kinematics during skiing and snowboarding.
Aim: This study aimed to quantify the daily frequency and magnitude of iMG-determined Head Acceleration Event (HAE) mechanisms (direct contact, indirect contact, and voluntary movement) experienced by park and pipe athletes within training environments (discipline, modality, and skill acquisition stage). The secondary aim was to determine whether similar trends were observed in the energy metrics.
Method: A convenience sample of high-performance athletes aged 14 years or older who were trained with Snow Sports NZ (SSNZ) participated in this observational study to measure HAEs during training sessions. Athletes were skiers or snowboarders in the elite or development programme competing in Halfpipe, Big Air or Slopestyle events. Data were collected using a custom-fit iMG worn by the athletes during their daily training. Acceleration events (AEs) were collected by the iMG and verified as HAEs via filmed training analysis. Key metrics included peak linear acceleration (PLA, g), peak angular acceleration (PAA, rad.s-2), maximum head impact power (MaxHIP, W) and maximum rotational head impact power (MaxRHIP, W).
Results and discussion: The iMG data were collected from eleven athletes over 23.9 training hours during the winter seasons of 2022 and 2023 in New Zealand. Of the 940 verified HAE, each of the eleven athletes recorded a frequency of 30.23±28.75 HAE/hour and the median magnitude and interquartile range (IQR) for PLA and PAA was 4.01 [IQR 3.52 - 4.85] g and 82.79 [47.50 – 142.55] rad.s-2, respectively. The PLA and PAA medians were notably lower than those reported in similar studies on contact sports. Slopestyle PLA was significantly greater than Halfpipe, and both were greater than Big Air. The PLA for the push skill acquisition stage (learning tricks) was significantly greater than that for both drill (perfecting tricks) and play (fun tricks). The push stage was significantly greater than the play stage for the PAA. The lack of significant differences in HAE mechanisms for the “safe” airbag versus snow landing was surprising, but perhaps trying risky manoeuvres on the bag increases the HAE magnitudes. MaxHIP and MaxRHIP presented patterns similar to those of PAA and PLA, respectively.
Conclusion: Significant differences in HAE magnitude were found between the disciplines and skill acquisition stages, and perhaps landing on the airbag is not safer with respect to HAE magnitudes than landing on snow. This research has established a protocol for future investigations with the iMG and practical applications for snow sports athletes. Further research into HAE during competition is pertinent for an increased understanding of HAE in snow sports athletes, and potential preventive strategies to reduce greater magnitude HAE are recommended.