In a bid to enhance player safety, smart mouthguards with advanced, sensor-equipped gumshields were introduced in 2024 to measure the forces rugby players’ heads experience during contact and enhance concussion management.
They record the magnitude and direction of collisions in real time, instantly alerting independent medical staff if an impact exceeds safe G-force thresholds.
These measurements are run through a mathematical model to estimate the players’ risk of injury.
However, University of Otago School of Physical Education, sport and exercise science researcher Prof Melanie Bussey said the model did not account for people of different sexes, ages and sizes.
‘‘The problem is that almost every commercial system uses a one-size-fits-all approach, assuming every player has the same head as a 50th-percentile adult male, whether they’re a 10-year-old girl or a 130kg premier men’s player.’’
Prof Bussey called for researchers, the sports technology industry and governing bodies to incorporate sex and size-appropriate scaling into their injury monitoring systems to ensure all players were protected.
Published in the Journal of Biomechanics, the study analysed videos of more than 15,000 head acceleration events from 572 community rugby players, aged 10-38 and weighing 34kg-142kg.
Prof Bussey said the researchers then assessed the risk of injury using suitable models.
‘‘When we applied a female-appropriate head model to female players instead of the male default, estimated injury risk scores changed by up to 54%.
‘‘We already know that injury-prediction models perform inconsistently for female athletes.
‘‘Using the wrong head parameters makes that problem worse.’’
For lighter youth players under 55kg, switching to a more appropriate smaller head model reduced predicted rotational power by over 60%, she said.
‘‘Crucially, this also affected whether individual impacts were flagged as high risk or not, meaning the wrong model could lead to players either being unnecessarily pulled from the field, or serious impacts being missed.
‘‘This is important because symptoms are not always obvious at the time of impact.
‘‘Players may not immediately recognise, report or connect symptoms to a particular incident and in community and youth sport there is often limited medical support on the sideline to observe every contact event.’’
Objective impact data could provide an additional layer of information to help identify patterns of exposure and better understand how head impact load may relate to symptoms, recovery and player wellbeing over time, she said.
‘‘Ultimately, the goal is to use this information to reduce unnecessary head impact exposure while preserving the benefits of participation in sport.
‘‘If we can identify where higher loads are occurring, we can work with coaches, players, and sporting organisations to adapt training, improve technique and develop ... policies that better protect players.’’
Even a simple fix — such as using a minimum of three different reference models based on sex and body size — substantially reduced the present ‘‘bias’’ in the data analysis from the smart mouthguards, she said.
‘‘Our study shows that using the right models for the right players makes a big impact.
‘‘If we want smart mouthguards to improve safety across the whole game, then the modelling behind them needs to be inclusive.’’
