Were microchipped mouthguards the key to Harlequins’ success?

That Harlequins are the champions of England is one of the great imponderables, given the bleakness of their midwinter. Many a retrospective has been performed on how they did it, most theories drawing out the virtues of rugby with a smile on its face.

Perhaps the key does indeed lie in those perpetual smiles. Or more specifically in the mouthguards revealed by them, and the little chips encased therein. Quins were one of three teams in the Premiership last season to adopt a technology called Protecht, through which they were able to monitor accurately and in real time every single significant impact, direct or indirect, to every single player’s head.

Related: Rugby’s problems run much deeper than concussion from the odd ‘big hit’ | Michael Aylwin

This season all Premiership teams will wear these mouthguards, as rugby union tries to find a way out of its head-injury crisis. The smartest clubs will use them, as Quins did, for much more than data collection.

Perhaps because of the hopelessness of their situation in January, when Paul Gustard left, Quins ended up shaping their training methods around the new technology. No longer did they rely on tackle counts and informal chats with the players about how they were feeling. Now they had a forensic read-out for each of exactly how much punishment he had taken, or was taking, in any match or training session.

“On average, we were able to reduce the amount of contact in training each week by 40 to 60%,” says Mike Lancaster, head of medical science at the Stoop. “I say this tentatively, because I want to see how we go next season, but our player availability was the best it’s been in many, many years.”

So was the form – and, tellingly, freshness – of the squad as they raised the tempo, time and again, just as other teams started to flag. If the single easiest measure in response to the head-injury crisis is to limit contact in training, Harlequins have shown how players can benefit in the short term, let alone in later life.

The mouthguards are designed by a company called Sports and Wellbeing Analytics. This is far from the first time science has attempted to gauge the forces to which rugby players are exposed, but the benefit of the mouthguard, as opposed to sensors attached elsewhere, is that it is fixed to the skull.

“The acceleration of the skull is what you are trying to measure,” says Chris Turner, chief executive of SWA, “not of the skin or shirt. The sophistication of the sensors is the key development in the last four or five years. The size of them has shrunk dramatically.”

Which means a lot can now be packed into a player’s mouth and a symphony of percussions is revealed on a screen as rugby players go about their business. An accurate gauge such as this of the pressure points in a match is as important a tool for the future of the sport as any of those we wait for science to supply.

SWA spent three seasons working with the Ospreys and Swansea University honing the technology. Last season Quins, Gloucester and Leicester pioneered its use in English rugby. SWA have begun work in the women’s game, with plans to expand into school and community rugby, where early indications are that the rhythms are very different.

Data collection is the priority now, but already they have recorded more than 60,000 impacts in elite men’s and women’s rugby, 32% of which are from direct impacts to the head, which means that more than twice the number of events recorded at the skull are from impacts to the body. The mean linear acceleration of a direct impact to the head is 33g and the rotational acceleration 2,019rad/s2. Hits to the body are more than half as intense. Thus the overall toll of hits to the body, as experienced at the brain, is greater than that from those direct to the head.

This sobering realisation speaks to the latest thinking that it is not so much concussion that is the sport’s problem as multiple hits of a moderate intensity. SWA is able to demonstrate that in many cases a player fails a head injury assessment not because of one big impact that jars the brain but because of an accumulation, the last one no bigger than any other.

Another finding is the sheer frequency of the blows. Tackle counts and ruck counts barely scratch the surface.

“My perception of, say, a ruck is that it’s one event,” says Dr Chris Jones, SWA’s head of science. “Actually it could be five, because I’ve been tackled, I’ve recoiled, hit the floor, someone’s come in and kneed me in the head, which hasn’t been seen, someone else has come in, and so on.” Protecht will pick up each impact and quantify it.

Concussion, in such a scenario, could even be seen as a player’s friend. “It is actually protective against sustaining more impact,” says Jones. “You’re on enforced leave. If that player hadn’t been knocked out he might go on to pick up another 300g in accumulation. That 300 is going to be a lot worse in the long term than whatever the blow that knocks him out is.”

Rugby’s focus, so far, has been on the tackle, where most recorded head injuries occur. To date there is no evidence to suggest the interventions are having an effect on concussion incidence. But if accumulation of blows is the metric the tackle is not the key area. “According to the data we have, the highest frequency of head contacts occurs at the ruck,” says Jones. “That has been neglected compared to a number of other areas, which have been heavily scrutinised and adapted, to no real effect.”

So far, research into rugby’s attrition rate and the measures adopted in response have been predicated, by necessity, on little more than guesswork. Now the dynamics of rugby can start to be accurately anatomised.

As much as the romantics among us hate the encroachment of science into our passions, this kind of science, the science of welfare, is likely to determine whether the game we love is still around at all in 50 years’ time. Besides, if worked as adeptly as by Harlequins, the end result is more than enough to satisfy romantics the world over.