Flashing mouthguards that signal a head injury will soon hit the rugby field – are they a game changer?

When the Women’s Rugby World Cup kicks off this weekend, spectators will witness more than the usual thrills, skills and physical brilliance the code delivers – they’ll also see something completely novel: flashing mouthguards.

Designed to help keep professional players safer, these smart mouthguards flash when a player experiences a collision big enough to potentially result in a concussion. This is an advance on existing instrumented mouthguards, used in the professional game since the 2023 men’s Rugby World Cup.

The mouthguards contain accelerometers and a gyroscope to measure the size of collisions. If a collision exceeds the threshold for a head injury assessment, a light-emitting diode (LED) will flash red, alerting the player and officials.

The smart mouthguards can measure collision impact forces, the direction of the impact and the number of collisions for any player during a game.

Collision impact is measured in “peak linear acceleration” (the g-force) and “peak rotational acceleration”. Based on the data, a decision can be made to pull a player from the game for a head injury assessment.

The threshold for male players is a g-force of 75 and for female players 65. But problems with Bluetooth capability meant there could be delays between a player receiving a head knock and the data being downloaded. The new flashing mouthguards are designed to overcome this delay.

A head injury assessment is done off-field by a trained medical professional. Background is collected about the collision and the player’s symptoms. The player then completes memory and balance tests. If they fail the assessment they’re out for the rest of the game.

World Rugby is using the women’s World Cup tournament to introduce the new LED mouthguards, ahead of using them at the top level of the men’s and women’s game in general. In time, we may see them become more common in non-professional and youth grades, too.

What about amateur and junior rugby?

The primary purpose of the new mouthguards is to improve surveillance of likely concussions by reducing the time between a sizeable impact being detected and then reported to officials.

In turn, this may reduce the likelihood of a player experiencing a second large collision – and therefore keep them safer. Like other smart mouthguards, these new ones will also record all collisions in a game for longer-term monitoring.

The high cost of these innovative safety technologies has so far been prohibitive for lower and non-professional leagues. Aside from professional franchises, really only researchers have had access, given the nature of the hardware, software and 3D-printing process involved.

But that might be changing, with recent innovations by mouthguard companies bringing their products into a more viable price range for community rugby.

High quality “boil and bite” instrumented mouthguards currently retail for A$350, which is only about $100 more than a dentist-fitted custom unit. As the technology evolves, the price will no doubt reduce more.

The advantage of smart mouthguards is the objectivity they can bring to collision assessment in community rugby, something not available in the past.

Using a phone app linked to the product, parents, coaches or referees can see the size of impact a player has received in a collision. That then allows them to make a more informed choice about removing a player from the field.

It would also be harder for a player to hide a concussion and therefore likely reduce under-reporting. As well, our research shows concussions for junior players can occur well below the adult thresholds, so this type of technology and information could be very helpful.

Benefits for brain health

While these safety developments are potentially beneficial, junior and community rugby still relies largely on non-medically trained staff to identify possible concussions.

Despite greater awareness and concern about concussions, research indicates there are still many youth athletes and parents who don’t know how to recognise the symptoms. There also appears to be a stigma about concussion reporting.

We know that in New Zealand, Māori and Pasifika players appear to suffer from higher rates of sport-related concussion, but are less aware of and less willing to report symptoms.

Under-diagnosis and under-reporting can have significant repercussions for the future brain health of players – particularly children whose developing brains are more susceptible to the effects of concussion.

An early return to play following an unreported concussion can lead to a player suffering a second and worse concussion, which could have longer-term recovery implications for a young person.

Improved coach awareness is one area that would make a big difference, and there are already concussion recognition courses available such as RugbySmart in New Zealand and BokSmart in South Africa.

The flashing mouthguards on show at the Women’s Rugby World Cup can’t prevent concussions. But they represent another step towards better managing the risks and effects of concussions over a player’s season and career.

As prices drop and these technologies become more accessible, we will likely see greater uptake in community rugby, further improving player safety at the grassroots level.

The authors thank George Stilwell, Natalia Kabaliuk and Keith Alexander from the University of Canterbury for their contribution to this article.