Tackle Height

How has World Rugby come to the point of the 'nipple line' and 'armpit line'?

We spoke to Ross Tucker about the process of rugby attempting to lower the height of tackles.

CONCUSSION IS THE biggest problem in rugby.

It is why the sport is set to trial the ’nipple line’ and the ‘armpit line‘ with regards to tackle height, and it’s why rugby has already looked to crack down more severely on illegal high tackles.

The latest Professional Rugby Injury Surveillance Project for the 2016/17 season underlined the issue once again: concussion was the most common injury for the sixth consecutive year in English rugby, accounting for 22% of all match injuries.

original Concussion is a major issue for rugby. James Crombie / INPHO James Crombie / INPHO / INPHO

World Rugby has been looking to bring what it calls “an evidence-based approach” to remedying the issue for some time and feels it has made some progress.

The Head Injury Assessment [HIA] is now a very familiar part of rugby, though it’s worth remembering that before 2012 there was nothing like it and doctors were under pressure to make a diagnosis on the pitch in an average window of just 64 seconds.

The HIA is a way of attempting to treat the problem, but what about preventing it? That’s the question World Rugby has long been asking itself.

In 2015, the research that has led to the current law trials around tackle height began in earnest.

World Rugby started by compiling a video library of 611 HIA events in games from 2013 until the end of 2015, taking in the World Cup, Pro12, Top 14, Super Rugby, European Cup, Challenge Cup and the Premiership.

One of the global body’s full-time analysts, a patient man named Ben Hester, then coded each of the incidents, demonstrating that 76% of the head injuries occurred in tackles.

Therefore, it made sense to focus on the tackle as an area where further detail was required.

“You can’t come up with a prevention strategy unless you understand what you’re trying to prevent,” is how World Rugby science and research consultant Ross Tucker puts it.

So Hester coded each of the tackles that led to HIAs, assessing them across a range of variables including the speed of the tackle, the direction of the players involved, the type of tackle, the body position of the players, and more.

“It’s not just 611 head injuries and 464 tackles,” says Tucker. “Then what you have to do is look at tackles that didn’t cause head injuries so that we can have a denominator.

“Ben must have worked for five months because he had to code around 4,500 tackles. The world authority on this stuff is Ben because he’s seen more head injuries happen than anyone on the planet, I reckon.”

Tucker, a South African who is well known for his illuminating work in sports science, took over from there and carried out analysis on the data, pinpointing the factors that made tackles risky in terms of head injury.

Christian Lealiifano receives a high tackle from  Sammy Arnold Rugby has been attempting to clamp down on high tackles. Brian Little / INPHO Brian Little / INPHO / INPHO

Anyone interested in learning more about the coding and analysis process should read Tucker’s in-depth explanation on his website.

One of the most interesting findings from the analysis was that 72% of the head injuries in tackles were sustained by the tackler. 

The data also showed that the risk of injury to both players from a high-contact tackle ["when the tackler is upright"] is 4.3 times greater than a low-contact tackle.

Furthermore, head-on-head contact [again, "when the tackler is upright"] is 6.5 times more likely to result in a head injury than a lower head-to-hip tackle.

Working with World Rugby’s chief medical officer, Dr Martin Raftery, Tucker then brought the data before an expert group of players, coaches, referees and officials in December 2016 across two days in Dublin.

That group included Paul O’Connell, Eddie Jones, Steve Hansen, Alain Rolland, Nigel Owens, Agustín Pichot and Sophie Spence.

On the first day, Tucker presented the data, highlighting the biggest risk factors that make tackles more likely to cause head injuries: front-on direction of both players, active shoulder tackles, a higher tackle, an upright tackler, and the tackler accelerating into the contact, or tackling at high speed.

On day two, the experts discussed what rugby could do about the problem.

“I think this point is lost on some people who are critical,” says Tucker. “The strategies we’ve come up with since this research was published are not just from me and Martin Raftery.

“We can describe the problem but the solution is not ours to propose. That’s why we got Eddie Jones and Paul O’Connell and Gus Pichot and the rest of the expert group and said to them, ‘You tell us how to solve it.’”

Tucker says the debate was fascinating and the meeting resulted in World Rugby announcing a “zero-tolerance approach to reckless and accidental head contact in the sport” that came into effect in January 2017.

“The speed of tackles – no, you’re not going to tell defences not to run as fast into contact,” outlines Tucker of the thinking in the meeting of the expert group. “Direction of tackle – you can’t change that, it’s the way the game is shaped.

“Acceleration – that’s not going to work because of rush defence. During that meeting, the expert group said to us to focus on the low-hanging fruit: the biggest thing you can achieve change with is the height of the tackle.”

Paul O'Connell Paul O'Connell was part of the expert group. Billy Stickland / INPHO Billy Stickland / INPHO / INPHO

So how to bring about a lowering of the height of tackles?

“You either do it by more harshly sanctioning the current height [the line of the shoulders] or by literally lowering the height of the legal tackle,” says Tucker of the thinking in late 2016.

“The prevailing feeling at that meeting was that we would be better off harshly sanctioning the current height, rather than lowering it because there were some concerns around the practical implementation around a lower legal tackle height at that time.

“They told us not to forget about possibly lowering the legal tackle height, but they felt the first place to go was to more harshly sanction tackles above the line of the shoulders.”

So it was that World Rugby introduced two new categories of dangerous tackles, with the ‘reckless tackle’ carrying a minimum sanction of a yellow card and a maximum sanction of red, while the ‘accidental tackle’ was minimum a penalty.

As with the HIA, it already feels odd that the game didn’t always have these categories and the minimum sanctions, but Tucker points out that there was a backlash against the measures at the time.

“A lot of the media coverage was people freaking out and saying it would change the game. People said it would kill rugby.”

There was much focus around the ball carrier in that negative response but Tucker points out that all of these measures are about changing the behaviour of the tackler – who is most at risk of head injury – to the benefit of everyone.

“If you’re driving on the highway and the speed limit is 120km/h, who does that protect?” says Tucker. “The driver, the pedestrians, the people in other cars – it protects everyone.

“It’s the same thing here, you protect both people with the same law. The rugby lawbook, 99%, is written from the perspective of the ball-carrier. The tackler was the object of the change because they’re most at risk but the ball-carrier was protected too.

“If you lower the height of the tackler, the only way for the ball-carrier to get a head injury is whiplash or hitting their head off the ground.”

Over the course of 2017, it was Tucker’s job to track the implementation of the law changes around dangerous tackles and his analysis showed that, globally, yellow cards for high tackles went up 41% and penalties for high tackles went up by 64%.

George Bridge of the is high tackled by Jeffery Toomaga-Allen George Bridge is high tackled. Photosport / John Davidson/INPHO Photosport / John Davidson/INPHO / John Davidson/INPHO

Given that an illegal high tackle is 36 times more likely to cause a head injury than a legal tackle, the rise in sanctions against high tackles was positive in World Rugby’s eyes. And yet, there was some concern arising from the analysis.

Even accounting for the 41% rise in high tackle yellow cards, there was still only one yellow card being shown for every eight high tackle offences.

That contrasts notably with rates like 2.6 deliberate knock-ons per yellow card, one yellow card for every three ‘not back 10 metres’ offences, and a yellow card for every 1.3 lifting/spear tackles. The numbers don’t quite speak of a ‘zero-tolerance’ approach.

The early concussion data – which will take some time to properly collate and confirm – suggested that the increased focus on high tackle sanctions had seen concussion rates level off in many competitions, but it didn’t feel like World Rugby had found the solution.

Oddly, the Premiership proved to be statistically unique in that even after the increased sanction focus, there was a 36% decrease in yellow cards issued for high tackles in the English league.

The aforementioned Professional Rugby Injury Surveillance Project in March 2018 called for further investigation of this trend, while also asking World Rugby to consider lowering the legal height of the tackle.

That had already been very much in World Rugby’s thoughts.

In December 2017, they had convened a meeting of some of the world’s top defence coaches – including Ireland’s Andy Farrell, South Africa’s Jacques Nienaber and Wales’ Shaun Edwards – to discuss the role of tackle technique in the area of head injury.

With that technical insight in mind and the data from the increased sanctions at hand, a World Rugby council meeting in March 2018 provided the next opportunity for an expert group to discuss possible next steps.

Jamie Heaslip, Rachel Burford and Nick Mallet were among the experts this time around.

“We presented to them and showed that we’d achieved some changes and were encouraged by the progress, but we probably needed to do a bit more,” says Tucker. “During that discussion, lowering the height of the tackle was put back on the table – our initial expert working group had told us not to forget that.”

The other measure that came up in the discussion was the ‘high-tackle warning’ trial that World Rugby subsequently implemented at the World Rugby U20 Championship.

“The premise was that you could give the sanction for the upright tackle after the match, taking the responsibility and burden away from being solely on the ref.

Andy Farrell Andy Farrell and other defence coaches provided technical input. Dan Sheridan / INPHO Dan Sheridan / INPHO / INPHO

“You’re giving the referee more post-match support and the big advantage of the high tackle warning was that it would act as an education system as well because you’re sending the message to players around what you’re trying to change.”

That meeting in March 2018 was so evenly split 50/50 in terms of opinion on whether to trial a lowering of the acceptable tackle height or the high-tackle warning system, World Rugby decided to trial both.

The World U20 Championship in June saw match citing commissioners issuing ‘high-tackle warnings’ to any players who were deemed to have been “upright [not bent at the waist]” in the tackle. Each high tackle warning counted as ‘one strike,’ with two strikes meaning that a player would be suspended for one game.

In total, 11 high tackle warnings were issued at the U20 Championship and the preliminary medical data from the tournament says that the warning system reduced the concussion incidence by 50% – an encouraging figure.

The World Rugby U20 Trophy – involving nations like Fiji, Canada and Samoa – starts later this month and will see a lowering of the acceptable height of a tackle to “below the nipple line.”

Meanwhile, this season’s RFU Championship Cup in England will see the altering of the definition of a high tackle “from above the line of the shoulders to above the armpit line.”

While these measures are on a trial basis and only in these two competitions, the reaction from many ex-players, supporters and pundits has been very negative, with renewed accusations that World Rugby is going to ‘ruin’ the sport.

One common argument has been that lower tackles are more dangerous when it comes to head injuries but World Rugby’s data shows that this is a purely anecdotal viewpoint.

“There are some views that are biased,” says Tucker. “One person may have had concussions from one particular type of tackle and therefore their perception is that that’s the most common kind, but that person hasn’t seen 500 concussions.

“The risk here is defined as the number of injuries per 1,000 events. For every 1,000 tackles where you have two heads in close proximity, there are 11.7 head injuries.

“Whereas every 1,000 tackles where you have a head in proximity with a hip, you have about two head injuries.

“If you can swap high risk for low risk, it doesn’t matter that there will be more head-to-hip tackles – they will cause fewer injuries overall.

“Last year, seven people died in shark attacks and 12 people died taking selfies. Which is more dangerous? The sharks are more dangerous because those seven shark deaths are out of 1,000 people swimming with sharks, whereas every day 10,000,000 people take selfies.

“Risk is a function of exposure, so if you swap high for low the overall numbers will go down.”

Jim Hamilton Former Scotland lock Jim Hamilton has been critical of the trials. Tommy Dickson / INPHO Tommy Dickson / INPHO / INPHO

Many critics have argued that the lowering of tackle height will result in a host of other unintended consequences, but World Rugby insist they have mulled this over with their expert group.

“People think we haven’t considered the potential for unintended consequences, but we have. In this instance, one of the unintended consequences we have to be aware of is that the ball carrier might go lower and lower into contact.

“Personally, I’m not sure that’s going to be the case. The number one priority of a carrier is to break the contact but if he’s going that low, he’s not going to be able to stay up and keep the ball alive.

“No coach is going to tell his player to go straight to ground, they want their player to take three steps beyond contact.

“Even taking that into account, our data suggests that two players going into contact bent at the waist is still safer than an upright tackle.

“People saying, ‘They’re both bent at the waist and they’re just going to run into each other head first,’ the data suggests that the risk of that causing injury is quite low.”

So, World Rugby will code and analyse again in the U20 Trophy and work alongside the RFU to do the same for the Championship Cup, eager to see what difference the trials of a lower acceptable tackle height make.

The promising first trial run of the high tackle warning system in June has encouraged World Rugby to put in place structures to run a ‘shadow’ system for all major competitions during the upcoming season.

“There won’t actually be sanctions but we’re going to create a pseudo-match commissioner and have an independent review of all incidents and give hypothetical high-tackle warnings to see what impact it might have on the game,” says Tucker.

That process will involve several people assessing each game so incidents are reviewed by more than one pair of eyes, allowing World Rugby to be sure of the consistency of agreement around each incident.

Whether or not World Rugby communicates the hypothetical high tackle warnings to clubs and players remains to be seen, though it would certainly make sense to do so if the system is to be adopted into practice fully for the 2019/2020 season.

There is much of this road yet to travel and concussion remains a huge issue but World Rugby is content that it is now leading what it sees as a scientifically robust process of making decisions.

The ‘nipple line’ and ‘armpit line’ have provoked a reaction, certainly, but while much of that interest will die down, World Rugby will be tracking the data and looking to relay it to expert groups for further discussion.

And all the while, the likes of Tucker will be attempting to figure out how this rapidly-changing sport looks now.

“The next phase of our research is to monitor how the behaviour of players is exposing them to risk,” says Tucker.

“In other words, over the next year we’re going to monitor what kinds of tackles are common, how many head contacts there are.

“What we achieved with the previous study was a good snapshot of what behaviours the players were using over three years of rugby, and the process now is to begin to ask, ‘Has it changed?’

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