Red alert: Rugby to use mouthguards that flash after heavy impacts

Smart mouthguards that flash red to highlight significant head impacts will be used at the Women’s World Cup later this month.

The initiative from World Rugby is a progression of technology that was first brought to matches in 2021 and has been steadily developed since. LED mouthguards were trialled successfully in Major League Rugby and in the Under-20 World Championship this year, receiving the green light to be rolled out further.

Referees will be asked to immediately stop the match upon seeing these clear mouthguards turn red as soon as a player experiences a certain level of force in a collision. An alert will still be sent to a match-day doctor via Bluetooth to warn of a possible concussion, but the hope is that another further visual cue enhances awareness.

Typically, at the moment, a player will be brought off upon a natural break in play after their mouthguard has been triggered. It is hoped that the flashing LED will both save time and reduce doubt as to which collision caused the head impact.

“Everybody will be able to tell when a player has sustained a big head impact,” said Dr Lindsay Starling, the science and medical manager for World Rugby.

“It will create awareness in the stands and for fans at home, as well as for the players and officials. It should mean that there is absolutely no delay in a player being pulled off for a HIA [head injury assessment]. Ultimately, this just helps to tell the story.”

The English Premiership and the United Rugby Championship will be among the competitions to follow the 2025 World Cup in showcasing the LED mouthguards, which have been developed by Prevent Biometrics and are installed with an accelerometer and a gyroscope to measure linear and rotational force.

After years of gathering data, scientists have set the threshold for an alert at 75Gs (g-force) for men and 65Gs, or 4,500 radians (measuring how fast something is rotating) per second, for either gender. These are categorised as the 99th percentile of collisions.

Wallaby Carlo Tizzano suffered a blow of just over 54Gs of force when he was struck by British and Irish Lions breakaway Jac Morgan during the second Test of the recent series.

Carlo Tizzano and Jac Morgan collide at the breakdown.Credit: Stan Rugby

Dr Starling stressed that the mouthguards should not be regarded as concussion detection devices. This is because impacts this large do not necessarily yield a concussion diagnosis, whereas smaller impacts might do so.

Dr Eanna Falvey, the chief medical officer at World Rugby, explained that there has been “full opt-in” from players ahead of this year’s Women’s World Cup, which begins on August 22 when England take on the United States in Sunderland. Currently, players who choose not to wear a mouthguard do not have access to the in-game assessment, although this has not stopped some from declining to use one.

Dr Falvey would love to see the tool become mandatory, though conceded that “personal choice is an important thing”. “I think, with the way it’s going, it will be ubiquitous pretty soon,” he added.

World Rugby is comparing data with the NFL in the US, and there are pilot programmes for smart mouthguards taking place in the NRL and AFL.

Dr Starling said that broadcasters have inquired about airing the g-forces of big tackles during matches. These proposals have been turned down so far because of medical confidentiality, yet could come to screens in future.

“It’s classified as medical data about a player, and so therefore we can’t share those numbers anywhere,” said Dr Starling. “But we’re working with the players to get them on board to want to share that information.

The mouthguards will flash red to indicate heavy impact.Credit: Getty/Supplied

“There is a very fine line between big and being safe and correct and the player being looked after. Because big isn’t always good; sometimes it’s bad.”

Highlighting foul play could be another potential benefit to the LED mouthguards. “It’s definitely something that’s been popping up over the last year where there have been incidents,” said Dr Starling.

“The thing that’s quite hard is sometimes small knocks are also bad and so you could easily have a foul-play incident that actually hasn’t caused much of a knock. What we need to be careful not to do is over-rely on the data.

“I think there is a world in which the data from the mouthguard can start to come into play a little bit more with foul play, but what I think everybody needs to understand is that in the same way a player can get concussed from a pretty small head impact, foul play [can have occurred] without registering anything substantial.”

LED mouthguards currently cost about $400 and require a custom dental scan.

London Daily Telegraph