And how in the heat of a match can club medical staff adequately protect athletes who, like cricketer Steve Smith in the second Ashes Test, are concussed but not yet showing symptoms? Throughout this football season, players at four AFL and four NRL clubs have been collecting data which, if proven to be reliable, may help answer these questions. For every tackle and bone-jarring hit, a series of tiny motion sensors fitted into customised mouthguards have recorded the forces at play. Fremantle's Nat Fyfe had to be helped from the ground after the brutal head clash with St Kilda's Josh Battle. Credit:ninevms The data is used to quantify the impact on the brain according to two measures; linear g-force and what researchers suspect is the knock-out punch, rotational acceleration. The project is the brainchild, quite literally, of HitIQ, a Melbourne-based tech startup that will next year expand its cross-code trials in the NRL and AFL and move into rugby union and US college football.

Mike Vegar, the managing director of HitIQ, says the aim is to give team doctors objective data to help diagnose and rehabilitate athletes from brain injury. Although our understanding and treatment of concussion is much improved from 20 years ago, experts still don’t know what separates a heavy hit from a potentially damaging one. “We have struggled to determine the cause and effect relationship,” Vegar tells The Age and The Sydney Morning Herald. “We don’t know what is happening on the field.” The NRL hopes the mouthguards will give club doctors more information when diagnosing concussion. Credit:Jonathan Carroll From next season, emerging technology may open a real-time window. Rather than having to wait until after a match to download data, Bluetooth-equipped mouthguards will transmit information from a player on the field to the phone of a club medico standing on the boundary line. By the time an injured player reaches the bench, his or her doctor will be armed with a read-out about the forces their brain has just absorbed.

About 60 AFL players from St Kilda, Essendon, Carlton and the Western Bulldogs wore HitIQ mouthguards this season. In the NRL, players from Manly, South Sydney, Brisbane and the Melbourne Storm took part in a volunteer trial. The AFL is considering a larger trial next season involving more clubs while the Australian Rugby Union has reached an agreement with HitIQ for the mouthguards to be available to Brumbies and Rebels players. The HitIQ mouthguard has been tested at a number of NRL and AFL clubs this season. Credit:Justin McManus NRL medical officer Paul Bloomfield said the league and the players' union were supporting the project. "If the research is successful, it could potentially provide us with another support tool to help identify possible head injuries requiring off-field assessment by the club doctors," he said. The research is being led by University of Newcastle neuroscientist Dr Andrew Gardner, a leading authority on concussion in sport.

Dr Gardner is still analysing data from the 2019 season trials but has so far seen nothing to disprove his assumption that rotational acceleration holds the key to better understanding sport-related brain injuries. Dr Gardner says the different forces measured by the mouthguard are best explained by the sweet science. In boxing terms, linear force is the straight jab. It is delivered with a jolt but rarely ends a fight. Rotational force lands like a right hook or uppercut to the jaw, knocking a fighter’s head off its axis and causing the brain to twist inside the skull, damaging connective tissues and disrupting essential functions. “We strongly suspect that those rotational forces are the ones causing the most disruption to normal brain networks,’’ Dr Gardner said. “From previous research we also know that rotational forces are the most difficult to validate.”

When Fyfe and Battle clashed heads earlier this season, Battle was wearing one of the data mouthguards. The readout from his impact with Fyfe shows he absorbed a substantial, linear force of nearly 54Gs but a relatively moderate amount of rotational acceleration. If you closely watch footage of the incident, you can see Fyfe slightly turns his head just before the moment of impact. He has no memory of the incident but later complained of having a sore jaw. If he was wearing a data mouthguard, it would have likely shown his rotational acceleration readout going through the roof. The mouthguard being tested on a crash dummy. Credit:Justin McManus Two further data sets shared with The Age illustrate the twin forces that impact on the brain in a head-high bump. The first records the moment Doulton Langlands, a young St Kilda player, collides with an opponent in a state league match. The incident appears innocuous but the data is stark; Langlands is hit with less linear force than Battle but his rotational acceleration reading is twice that recorded by the St Kilda defender. He is concussed and takes no further part in the game.

The second data set records the impact of Collingwood’s Travis Varcoe flashing through a pack and taking out St Kilda’s Jack Lonie. Again, this incident was not out of the ordinary. The impact looks more severe than the Langlands incident but the data shows otherwise. The linear force is stronger but the rotational acceleration is far weaker. Lonie is left shaken but uninjured. The data from the 2019 trials, which is yet to be shared with the AFL and NRL and their clubs, will provide the first detailed picture of the amount of punishment a footballer’s brain absorbs during a match. Dr Bruce Reid, the Essendon club doctor for 37 seasons, said the study would provide information on every knock – not just those which resulted in concussion – and better inform an emotive debate about the risk of head injuries in the different football codes. “We could get some real evidence about how much significant trauma we have to the brain during training games,’’ Dr Reid said. “In Australia, a lot of parents are worried, reading what is happening in America, where they train and clash heads non stop. They are thinking the AFL is like that.

“The trouble is, we don’t have the evidence. I don’t think we get many knocks to the head compared to other sports but at the moment, we can’t say rugby is worse than us, it may not be. This is going to give us real data.” The mouthguards are embedded with three accelerators which collect data through 14,500 sample points. To work properly, each mouthguard must be custom fitted to a players’ teeth and calibrated to the dimensions of their head. By fitting the mouthguards to the maxilla, the fixed upper jaw, the sensors are in effect attached to the skull. Steve Smith was hit on the head in the Lord's Test by a ball bowled by England's Jofra Archer. Credit:Nine The data, if validated by further studies, is not intended to replace clinical methods currently used by doctors to diagnose concussion, such as monitoring a footballer for loss of balance, memory and cognitive function. Rather, it is designed as a concussion warning system to alert doctors when forces which usually lead to brain injury have been recorded. This could be an important tool for doctors in cases such as that of Steve Smith, who was felled by a Jofra Archer bouncer during the recent Lord's Test match but did not show signs of concussion until after he returned to the crease.

“Quite often you don’t show symptoms at the time or on the sidelines,’’ said Ben Nizette, the chief technology officer of HitIQ. “We saw that with Steve Smith. HitIQ's Ben Nizette says the mouthguards make it easier to pinpoint players who are at high risk of a concussion. Credit:Justin McManus “If a detection tool is working properly, like our mouthguard, what we can do is we can flag somebody who is at high risk of a concussion even if they don’t show signs and symptoms at the time, and help medical professionals make the best decision about a return to play.” HitIQ is close to finalising terms with Brigham Young University in Utah that will see Cougars footballers wear their mouthguards next season.