Protecting the rugby player’s head – the paradox of tackler height and head injury

13 Aug 2019 Posted by

Why a red card? The tackle shown to the right saw New Zealand’s Scott Barrett sent off this past weekend against Australia, and it has triggered substantial discussion. The red card was the result of the application of a new World Rugby High Tackle Sanction Framework by referees, which is aimed at a) increasing sanctions for dangerous play to reduce head injury risk, and b) improving consistency in decision-making.

That framework is going to be a magnet for discussion and criticism in coming months, particularly under the bright spotlight of the Rugby World Cup. But its development wasn’t an overnight ‘guess’, and certainly wasn’t arbitrary. It was the result of years of research and discussion that then triggered focussed interventions with easily a hundred people involved in the sport in capacities ranging from playing and coaching, to competition organizing.

It began in late 2016 with a “zero tolerance directive” after a multidisciplinary group met to discuss head injury risk based on video analysis of head injuries. That was launched in January 2017. Then came numerous iterative discussions identifying the need for a framework to support those high tackle decisions, which then went back and forth within a multidisciplinary Group including Match Officials, medics, judiciary, citing etc. It was then discussed and modified at a dedicated Player Welfare safety meeting in France, and again during the following approval steps: Law Review Group; Rugby Committee, Council and EXCO.

It is a journey whose background is worth knowing about, rather than simply saying “Game’s gone soft” and accusing the referee of “hiding behind the laws”.

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The overall purpose

The bottom line, or top line, if you wish to stop reading here, is to reduce the number of times high risk head impact occurs in matches. That means head impact to the ball carrier (the obvious) and the more risky head impact to the tackler (less obvious).

And the theory is that harsher sanctions for high tackles are meant to act as a “stick” that achieves one of two things (or both):

  1. Lower the height of tacklers and the associated body position of tacklers into what is a safer, lower risk position for their heads (based on data, explained below)
  2. Change the technique or technical execution of higher, upright tackles so that head contact is avoided or reduced

Both of those are means to an end. The path taken to reach that “end” is up to the coaches and players, and whether they choose to adjust to different tackle types and heights (option 1), or to focus on technique in the higher risk tackles (option 2). But the premise is that sanctions – penalties and cards – are the message to trigger those necessary adjustments.

There’s a lot behind that message, and so this is a post in which I want to try to explain the data side of the process of risk reduction, how the risk factors were identified, why certain decisions were made, who made them, and what the intention of zero tolerance on head contact actually is?

There are a few important principles that underpin the risk reduction approach, and understanding those is key. The most common rejection of the high tackle sanction approach involves something like the following: “Given that 70% of head injuries happen to the tackler, this approach of giving out cards is not going to help anyway, it’s focused only on the ball carrier, and the tackler is being neglected. Asking the tackler go lower will increase their risk. You’ll hear coaches and pundits say this, maybe even some in the media.

In this article, I want to try to explain to why this is untrue. So bear with me, and I will try to describe the method behind what you may see as madness. I apologize if this gets lengthy, but please, if you are interested, read it and share it widely. Point by point, here we go.

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The background: What is risky?

  1. Concussion is the most common injury in professional rugby. It probably has been for a while, but since about 2011, the combination of increased awareness (some of which came across the Atlantic from the NFL), better tools and a lower diagnostic threshold for detecting and diagnosing concussions have led to more of them being identified. As you read this, the global concussion incidence is about 16 to 18 per 1000 hours of rugby. That works out to about 2 concussions every 3 matches. Given the uncertainty over the future prognosis and health of people with multiple concussions, this is a good reason to ask not only whether they’re detected and managed, but “how can concussion be prevented?

2. You can’t prevent something if you don’t know how it happens. So step 1 in prevention is to develop a good understanding of risk. This means knowing:

“Who is likely to have a head injury?”
“In which event or phase of the game is the injury likely to occur?”
“What factors or circumstances around that phase or event increase the risk?”

3. Between 2014 and 2016, 611 head injury assessment events in global professional rugby were analyzed to try to answer those questions. That research study found that the majority of them – 464 or 76% – occurred in the tackle. No surprise there. Next highest was rucks, 73 out of 611 (12%). Also no surprise. The tackle, by virtue of being the most frequent match event, with the highest risk( that is, number of injuries per 100 tackles), became the focus of the next phase of analysis.

4. Slightly more surprising, of head injuries that happen in the tackle, 72% occur to the TACKLER, and 28% to the ball carrier. So the tackler has a risk that is 2.6 times higher than the ball carrier. You can read more about this in a thread I wrote towards the end of last year. This finding was somewhat surprising – most injuries show a 50/50 split. It is also the source of “misinformation” and misunderstanding, so let’s look at this a little more closely.

5. If you were told that the tackler is almost three times more likely to be injured than the ball carrier, what would you do? How do you protect a player from themselves? How do you reduce the risk when the risk is created by the player who initiates the risk event? I hope that you can see the paradox here, the challenge that this creates for a law-maker, because typically, the law protects the recipient of an action (“Don’t shoot someone, they’ll get hurt”) rather than the initiator of the action!

6. With that in mind, I’ll try to explain how the various groups went about addressing this paradox. The first requirement is that you have to understand why and when the tackler has an increased risk – it comes down to mechanism of injury. There’s no way around this. You’ve got to ask “What actions or behaviours expose the tackler to risk?”. This allows you to create a spectrum of risk, like the one shown below, and then work with specific experts to figure out how to move behaviour from right, in the red zone, to left, in the green zone.

7. So the key question is this: “What attributes or characteristic of a tackle tend to lie in the red zone, on the right hand side of that spectrum, and what lies in the green zone, on the left side?”.

8. The reason this matters is because when you’re trying to reduce risk, you have to know whether you’re going to eliminate the risky stuff (the red), or are you going to substitute high risk for low risk? There’s a crucial difference between the two approaches. If you’re going to eliminate risk, it’s easy in theory – you simply ban the stuff that lies in the red zone, and it’s done with. For instance, you could make it illegal to drive any car after 8pm, and you would guarantee a huge reduction in the number of drink-driving cases. It would also be wildly infeasible, but in a theoretical world, such a ban could work. However, if you can’t eliminate something completely, then you’re probably going to have to substitute it for something else (for instance, take the bus or an Uber after a night out).

To bring this analogy to rugby, if there’s a certain type of tackle that has high risk, can you ban it completely? Or are you more likely to try to swap it for a tackle that is lower in risk? To do this, you have to first know what’s likely to be swapped with what.

That is, what is your A (high risk tackle/driving after drinking) and what is your B (lower risk tackle/taking the bus)? Once you know that, you can ask how you might shift players from A to B? From red to green. This is where your “levers” come in, and that’s where this process was ultimately headed from day one. The data collection began knowing that eventually, we’d need to ask coaches, players and referees how to swap high risk for low risk behaviours.

9. So, below is what that risk spectrum looks like for 464 tackle head injury events (that needed HIAs). In a follow up post to this, I will use the U20 Championships to explain exactly how risk is worked out, and walk step by step through some examples, so check in later for that, but basically, this is a spectrum that was generated by analyzing the 464 HIAs from tackles, and another 3000 tackles that did NOT cause a head injury. By comparing injuries to non-injuries, you can work out what circumstances are more likely and less likely to cause a head injury. This is called propensity, and it is calculated as number of injuries per 1000 of that kind of event.

10. Ok, so we’re making some progress. We see some obvious things in the red zone – higher speed increases risk, accelerating is more dangerous than not accelerating, front on tackles have more risk than side on or tackles from behind. Most people will have anticipated these differences.

Less obvious or intuitive is that “higher tackles” are more likely to injure players than lower tackles, and that “Upright players” create more risk than “bent at the waist players”. This applies to both the tackler and the ball carrier, take note, so both the tackler and ball carrier have lower risk if they’re bent or upright. These are crucial points, so let’s look at them more closely.

11. A “higher tackle” is a legal tackle, but one where the head of the tackler is at or above the shoulder of the ball carrier. In other words, contact is at the ball carrier’s sternum or higher, and the tackler and ball carrier’s heads are sharing ‘air space’.

A lower tackle is one where the tackler is making contact on the lower trunk or torso, or the legs of the ball carrier. In this scenario, the tackler’s head is in proximity with the lower trunk, hips, upper leg, knee or feet of the ball carrier. Imagine a line across the chest at the level of the sternum, or under the armpit – that’s the line separating high from low tackles in this analysis.

12. Linked to this is “upright players”. This has a clear definition for the tackler – it is a tackler who presents the front of their chest to the ball carrier prior to contact, as opposed to the top of their shoulder. Or, if unclear, the tackler’s feet are directly beneath their shoulders and their spine is vertical at impact. It stands to reason that typically, an upright tackler’s head will be near or close to the head or shoulder of the ball carrier (unless the ball carrier is bent – see later). And so “upright tacklers” and “higher tackles” (see point 11) are related, to some degree. One tends to cause the other.

What the research found was that upright tacklers were 50% more likely to be injured than bent at the waist tacklers, and that this was true irrespective of the ball carrier’s position. It is rugby’s prisoner’s dilemma – it doesn’t matter whether the ball carrier is upright or bent, the greater risk comes when the tackler is upright.

13. This is key – a tackler who is upright is MORE LIKELY to have a head injury than one who is bent, and at a global level, ball carrier position doesn’t affect this relative risk. Why? Because it is more likely that the upright tackler will have a head to head or head to shoulder contact, which is a “higher tackle” contact and more dangerous. Below are the specific numbers relating these risks to one another for tacklers.

You’re looking here at the PROPENSITY spectrum for each situation to cause a head injury to the tackler. Propensity is risk – it is the number of head injuries per 1000 such tackle situations. Alternatively, you can think of it as “how many such tackles happen before a head injury to the tackler?”, which I have also shown in this figure (the 1 in 89, for example).

14. So, what we have is head to head contact causing a tackler head injury 11.3 times per 1000 such tackles. Or, once every 89 situations where heads are in proximity. Look at head to hip contact – that injures the tackler 1.7 times per 1000 such tackles, or 1 in 581. In other words, a head to head impact is more dangerous (6.5 times, to be precise) than a head to hip impact. (Just a note on the actual numbers – these data come from a time where the HIA number was an underestimate, due to lack of adherence with the ‘new’ process. The numbers in the current game will be higher, across the board, because the HIA number in 2018 is about 30% than it was from 2013 to 2015)

15. When we group tackles by those where the contact is above the blue line (higher tackles) and those below the blue line (lower tackles), we get an overall picture that says the following: “Higher contact tackles, where the tackler’s head is above the sternum, near the shoulder or head of the ball carrier, are 4.25 times more likely to cause injury than lower tackles, where the tackler’s head is below that line”. The risk is 3.8 HIAs per 1000 high contact tackles, and 0.9 HIAs per 1000 low contact tackles.

This is why “Higher tackles” are in the red zone of the spectrum, and lower tackles are in the green zone of the risk spectrum. Note also that Upright tackles are 1.5 times more likely to cause a head injury than bent at the waist tackles.

16. Yes, head to knee impact has high risk. A head injury occurs once every 323 tackles at this very low tackle height (3.1 HIAs per 1000 situations). That’s almost twice the average risk, so of course there’s reason to worry about these – you wouldn’t want players diving in recklessly, eyes down, head first, because a) the head injury risk is quite high, and b) it increases risk to the ball carrier’s knees.

But note that the head injury risk for the tackler is still lower here than head to head risk. So given a choice, where it’s only about the tackler’s head, which would you advocate? (a reductionist question, I know, but to emphasize a point). Head to hip is even lower still. Where you really want the tackler’s contact, especially for those high risk active shoulder front-on tackles, is head to upper body or trunk (as future evidence would confirm).

17. But when you watch rugby, you will see loads of head to hip head concussions. They stand out, right? More than any other kind (the data support you on this). Perhaps you’ll conclude that head to hip, or head to knee is most dangerous because that’s what you see more of, as an absolute number.

But this common approach to the issue overlooks the key principle of reducing risk, namely that it’s not about the number, but the likelihood of injury. Why? Because your approach here is not to eliminate risk, but rather to swap A for B, and that’s a risk problem, not a numbers one.

Here’s an analogy: Imagine you counted up all the people who die in car accidents every year, as well as those who died in motor bike accidents (sorry for the morbid analogy). You’d count, for argument’s sake, 1000 car deaths, and 40 motor bike deaths. Would you then conclude that cars are 25 times more dangerous than bikes, and thus suggest that everyone should rather ride motor bikes as part of your overall road safety initative?

Of course not! Why? Because you haven’t accounted for EXPOSURE to risk. And you can’t make any kind of “risk swap” decision unless you know how many people were driving cars (and how far they drive) compared to motor bikes. You have to know this total in order to work out the likelihood of the event, and only then can you suggest that one risk be swapped for another.

Imagine for instance that there were ten million kilometers of car journeys, and 100,000 kilometers of motor bike journeys that year (people are 100 times more likely to travel by car in my analogy). Suddenly, the numbers take on a new meaning. The risk from cars would be 100 deaths per million car kilometers, and 400 deaths per million motor bike kilometers. Motor bikes are four times more dangerous than cars. And so your strategy to reduce OVERALL deaths would be to advise that people replace motorbike journeys with car journey – if they’re going to travel, choose the one less likely to cause the negative outcome per exposure, or per kilometer (traveling on buses or trains is likely safest of all, by the way).

18. My point is this – when people say that they see more concussions from head to hip or head to knee, they may be mistaking volume for risk. Unless one knows how many COULD have happened, one can’t properly assess risk. This is why you have to look at exposure to get the denominator, and that’s what produces the risk spectrum.

19. And so we come back to the absolutely crucial point about risk reduction and the “swapping” of behaviour that I explained in Point 8 above. Remember, we have to identify what has relatively high risk (A) and what has lower risk (B), because we’re going to swap A for B.

So the question that matters is this:

Of two options, which is LESS DANGEROUS to the tackler?  Is it to have the head in close proximity to the ball carrier’s shoulder and head, or is it to have the head in proximity to the hip, upper leg and knee of the ball carrier? The spectrum and propensity answers this:

20. Now, let’s return to the question I asked YOU in point 5 above: How will you protect the tackler? What will you change in order to reduce the risk of a head injury to the player who initiates the event?

I hope that you’re thinking about it and recognizing that you’ve got to move from right to left, from red to green on the risk spectrum. And given what you’ve seen about what is risky, I hope that you’ve realized that if you can reduce the number of head-to-head impacts in the sport, then you’re going to reduce overall risk. If you can get the players heads out of one another’s airspace, then concussions should fall, compared to when heads are near hips, and even knees.

And it doesn’t matter if you replace head-to-head with head-to-knee or head-to-hip impacts, overall risk should fall. Your best option is to swap those bad head-to-head contacts for head-to-upper body and upper leg contacts (though there’s an interaction effect of different risk factors in player here, but I won’t go into that now)

21. Linked to this, if you can get the tackler into a bent position more often, where those higher head contacts are less likely, then provided you do so at the right time, the risk is going to be lower. What does “at the right time mean”? It means reacting to the dynamic situation created by the ball carrier’s movement because there are some situations where the tackler can avoid head contact by staying higher or upright.

So this is not a black and white, hard and fast “rule” saying that lower is always better (though some frame it that way). Rather, this is about priority 1 – avoid head contact for both players. Generally, that’s less likely to happen for a bent tackler, but not always. There is a recognized complex interplay, but the big picture is quite clear. It’s not about saying “You must go lower”, it’s about saying “go where you have less chance of dangerous head contact”.

22. Taken together, what we have is a picture that says the following:

Priority 1 – avoid head impacts for both players, especially from higher contact. In particular, avoid a tackler’s head striking a ball carrier’s head, or being above the ‘blue line’ for higher contact. Second priority – avoid head to knee impact for the tackler. But if it’s one or the other, lower is better, higher is worse. Not from illegally high tackles per se, but from head to head and head to shoulder collisions, where there is “higher contact”. Of course, any head contact is worse than none, but this is clearly the highest risk one.

And how do you avoid head impacts? Two ways – one is to improve technique when tackling higher, the other is to tackle lower, rather than higher. All that matters is that you create swap the relatively high risk head impacts to the tackler with the relatively low risk impacts.

We have now identified the desired “destination”.

23. That destination is to avoid head impacts for both players. It should be obvious that the risk to the ball carrier will be much lower if this destination is reached – the only way a ball carrier can be concussed from a low tackle is if their head hits the ground or if they suffer whiplash. These do happen, but very rarely (under 9% of total). So if you can get the tackler away from the ball carrier’s head, then it is obvious that head injury risk to the ball carrier is going to drop dramatically.

But, we’re interested in the tackler, who is injured 2.6 times more often. And really, this is the only question that needs to be asked:

Of two options, which is LESS DANGEROUS for the tackler?   Is it more dangerous to tackle upright/higher, or is it more dangerous to tackle bent/lower?

The spectrum above made it clear that in this study, globally, the LESS DANGEROUS option is to tackle lower, bent at the waist, or with technique that avoids the head of the ball carrier. And that’s the suggestion that was made by an expert working group consisting of coaches, referees, players and officials in late 2016.

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The data ends, and the interventions begin – zero tolerance to head contact

24. That expert working group was the point at which the science steps aside, and the practitioners take over. Science can describe the picture, but it can’t and shouldn’t suggest how to change it. So a group of expert players and coaches including Eddie Jones, Gus Pichot, Paul O’ Connell, Alain Rolland, Rachel Burford, and John Jeffries was convened, and spent two days in Dublin discussing all these risks. Their first conclusion and suggested action step was that risk could be reduced if behaviour was changed away from the “red zone” of high risk towards the “green zone” of lower risk.

25. How do you achieve that behaviour change? The recommendation made by that expert group was to more harshly punish illegal high tackles. They didn’t suggest only that – the issues of speed, acceleration, tackle direction and tackle type were all discussed, but those experts felt that the “low hanging fruit”, the approach that would be most readily accepted with the smallest possible ‘harm’ was to focus on the height and position of tacklers, as you can see in the summary below. The speed and acceleration issues were deferred for future discussions (and would result in, among other ideas, the 50/22 law trial, but that’s for another time)

Also notice that “Technique” sits atop everything – all the risk can be reduced with improved technique. They knew that, and spoke about that, but the question is “How do you compel people to address technique more?” Their suggestion was to more harshly sanction high risk tackles, using existing law to push behaviour from right to left on the spectrum.

26. And here’s where the paradox is hopefully resolved – illegal high tackles are not directly the cause of the head injury to tacklers, but they tend to happen when tacklers are executing actions that are higher in risk, namely upright tackles that involve higher contacts. These are the kind of tackle circumstances you want to avoid (the red zone of the spectrum), and so sanctioning the ‘extreme’ (illegal tackles) is an indirect way to get at the risky behaviours (legal, but high risk tackles).

27. So, given that there was already a law in place to sanction dangerous contact to the head of the ball carrier, the ‘lever’ suggested was to apply that law more strictly. The rationale from the expert group was that this would put responsibility on tacklers to avoid contact with the ball carrier’s head by targeting lower on the ball carrier’s body, thereby putting their own heads in a relatively safer position. This would reduce the risk of head injury to BOTH PLAYERS.

It was designed to compel coaches and players to say “OK, the consequences if I aim to tackle higher and get it wrong are going to be more severe, so I’d better reduce the risk of a yellow or red card by targeting lower on the ball carrier, perhaps at the upper trunk” (which is in our green zone, you may recall).

Alternatively, the player/coach could say “I’m still aiming higher, but I have to make sure I don’t strike the head of the ball carrier. It’s risk and reward, but let me work on my higher upright tackle technique until I can do it safely and effectively”.

Either scenario is positive because it avoids head contact for both players and that’s priority one.

28. And the crucial point is that in avoiding the head of the ball carrier, the tackler is also reducing their own risk of head injury. BOTH players benefit:

  • Ball carriers will benefit directly because their heads are totally out of danger of direct impact
  • Tacklers will benefit indirectly because their heads will be in the relatively safer position of being near the ball carrier’s torso/trunk, rather than the head and shoulder of a ball carrier. This is summarized below.

29. Based on that advice from the Expert Working Group, World Rugby announced a “zero tolerance” directive in January 2017, which identified a category for “Reckless tackles” and “accidental high tackles”.

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The global penalty and card spike, and a new set of challenges

30. As you might expect, this saw an increase in the number of penalties and cards in the global game. For the next 12 months, compared to the 24 before, there were 64% more penalties for high tackles, and 41% more cards.

It used to be that you’d see a high tackle penalty every 125 minutes, it became one high tackle penalty every 76 minutes. That equated to 6.4 high tackles every 10 matches before, and 10.5 high tackle penalties every 10 matches after. One a game, basically.

As for cards, that went from 1 high tackle yellow card every 13 matches, to 1 high tackle yellow every 9 matches. And red cards used to be given once every 270 matches, and after the zero tolerance directive, it become one red card for a high tackle every 56 matches.

31. So, as expected, right? Except there were two concerns. The first was inconsistency. The change was not uniform across all the world’s competitions – some competitions saw high tackle penalties go up by 90%, but their yellow and red cards actually went DOWN! You were half as likely to be sent off for a high tackle than before. Other competitions saw a bigger increase in cards than penalties, making it more likely you’d be severely punished for high tackles. So it was clear that the subjective judgement of officials around the world was creating large disparities in sanction for basically the same action. That would undermine any ‘zero tolerance’ approach, for obvious reasons.

Second, the issue was whether these changes were enough to cause the desired change in tackler behaviour? Look at those rates – one high tackle penalty per match, on average. That’s one every two matches for your specific team. One yellow card every nine matches on average, so your team would play 18 matches before getting one. There were more frequent yellow cards for deliberate knock-ons in some competitions, and other offences like ruck entry or offsides would be penalized 4 to 5 times per team per match. A high tackle was carded once every nine high tackle penalties. The ‘stick’ just wasn’t large enough, or used often enough.

The feeling, then, was that if the initiative was to work, then the sanction needed to be applied more often, more severely, and more consistently.

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The High Tackle Sanction Framework

32. And that led to the creation of the High Tackle Sanction Framework beginning in late 2018, completed in May this year. There is a straight line between the zero tolerance directive suggested by that first expert working group and this Framework, because the sport is still trying to achieve the same outcome, just with greater consistency.

You can read all about the frameworks’ aims, components, implementation, and then watch a video tutorial on it here. The decision-tree that constitutes the framework is shown below.

33. The idea here is that just as pilots use these kinds of processes to fly planes, and doctors use decision trees to diagnose disease (the concussion diagnosis process informed aspects of this framework, for instance), so too could a referee benefit from a logical, step-by-step process that identifies important aspects, links them to clear definitions, provides signs or indications of risk/danger, and then comes up with a final decision.

34. To use it, the referee first establishes whether they are dealing with possible foul play. If they are, then the initial decision is whether they are assessing a high tackle or a shoulder charge? Those are differentiated using the definition provided for a shoulder charge.

Once that’s established, they ask the same three questions, in the following order:

  1. Is there head or neck contact?
  2. What is the degree of danger? (and the signs or indicators of high danger are provided, based on what is known to increase risk of injury. The list is indicative, leaves the answer up to the referee’s expertise, but is not arbitrary – these are the ‘inputs’ that create the output of risk)
  3. Are there mitigating factors? Here again, a list of factors to consider is provided. And again, whether they are applied or not is up to the referee, who retains autonomy and authority in the process.

Questions 1 and 2 produce an initial decision, and then mitigation may be applied if it is clear and obvious. That produces a final decision, one that can be communicated with three answers to three questions.

35. The hope for the framework is that it will provide clear, logical decisions that can be understood by all. Note that I say “understood”, and not “agreed with”, because perfect agreement is impossible. Everyone knows this. Or they should. There will always be differences and subjective aspects to the decisions – some may say that mitigation was present and should have been applied, others may disagree. Some may say that a tackle has “low danger”, others may deem a tackle to be “high in danger”.

And this is fine – reasonable people can disagree on these junctions and factors. These same subjective aspects were there before the Framework, but few people verbalized them logically. So one consequence of putting the framework out there is that it will highlight any inconsistencies or omissions, creating the appearance of MORE errors (kind of like the cars vs motorbike problem, actually). But inconsistency has always been an issue, and the framework is meant to reduce it, creating more agreement between observers.

So the idea is that this process should improve reliability and increase agreement. It will definitely increase transparency (you’ll now know exactly why you disagree with the referee, instead of basing it on ‘feels’ and which anthem you happen to sing before a match), and ultimately, it should result in more consistent sanctions for the behaviour that the experts consulted throughout the process have identified as being undesirable.

36. Remember the premise here – the application of sanctions through penalties and cards is meant to make players adjust their technique to avoid the head of the opponent, with a side effect of exposing themselves to less risk. This may mean lowering the height by 10cm (see images above), or it may mean footwork, it may mean decision-making.

37. In the midst of inevitable over-reaction to the card decisions using the Framework, the most important thing to know about the Sanction Framework is that it is only in play when there is a dangerous tackle, and that cards will only be given if there is a shoulder charge, or head contact for the ball carrier.

In other words, the path taken through the framework is dictated by two things:
1. Whether the tackle is a shoulder charge, rather than one using the arms (Pathway 1 and 2 vs Pathways 3 to 5, see decision tree above)
2. Whether or not there is head contact from shoulder or arm? (Pathway 5 vs the rest)

If there is no head contact, the worst possible outcome is a penalty (Seatbelt tackle, see Pathway 5 in the Framework) because contact is still high. Or, it may be deemed a legal tackle, no foul play at all, depending on the ball carrier’s body position and height. The referee won’t even consider using the Framework then. This happens frequently in those pick-and-go situations where the ball carrier runs very low to the ground, head down, and actually initiates the head contact, which is often with the chest or upper body of the tackler. These happen 40 to 60 times a match, and people freak out about them for no reason.

The reason I emphasize this is that there can still be high contact on the ball carrier’s body, including to their head (ball carrier head into tackler torso, for example), but only if the tackler is assured of not striking the head with their shoulder or a forceful arm. The picture strip below shows three such examples, all from within a few seconds of the weekend’s match. One is dangerous foul play – the Barrett red card incident, with the Sanction Framework process spelled out beneath it – Q1, Q2, Q3, decision. Two are not. They never have been.

The point is, there is no obligation to tackle lower, just to tackle safer. And “safer” means avoiding the head, which sometimes means staying upright, or not putting the shoulder into the ball carrier’s head, even if it is clumsy rather than malicious. A big part of this is risk vs reward, and making players accountable for taking those risks. Ultimately, “safer” is the list of actions under the green zone of the spectrum, and may be achieved by a focus on technique improvement, irrespective of tackle type or height.

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Subsequent confirmation research

38. Perhaps at this point you’re thinking that this is a lot to base on one study. I had the same concerns. But since we did this, a few other studies have supported the theory. First, Matt Cross took a similar data set, and using a completely different analysis method, found that the high risk factors for head injury were speed, acceleration, and head contact. In other words, it confirmed the finding using different approaches to overlapping data.

39. Then Greg Tierney did a series of studies looking at injury and head biomechanics. One found that for front-on tackles, the highest risk direction, the propensity was lowest when tacklers targeted below the upper trunk for upper body tackles, and suggested tackling the lower trunk for lower body tackles and avoiding the upper legs. That echoes the spectrum we produced, where the safest zone is the torso of the ball carrier. It’s like a “Goldilocks zone” – not too high, not too low, just in the middle (with credit to rugby expert Ken Quarrie of New Zealand!)

40. Even more interestingly, Tierney also studied the mechanics of the head during tackling, and found that the ball carrier’s head linear acceleration, angular acceleration and change in angular velocity values were between 50% and 150% higher greater for upper trunk tackles than for mid/lower trunk tackles, which “support[s] the proposition of lowering the current tackle height laws to below the chest.” And granted, this study looked at the ball carrier’s head, not the tackler’s, but this emphasizes that you can greatly reduce the risk to one half of a tackle situation with a lower height, and as I’ve explained above, the tackler also has less risk when lower.

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Conclusion

Will it work? Everyone hopes so. Of course there are concerns. There were also other options – lowering the height of the tackle, for instance, to the armpit is one such option. That was explored unsuccessfully in England, where no reduction in concussion risk was found. So far, the same trial has been a bit more successful in Stellenbosch, but it’s early days yet. A trial proposed by France Rugby will soon explore lowering the height all the way down to the waist, which is basically the equivalent of giving the maximum possible dose of a drug and seeing what side effects it causes!

That’s why it’s interesting to trial – it may be the first step, it may be the last one, but you’ll never know until the step is taken. Based on the above, I think that too low is bad, too high is definitely bad and something in the middle is best. Also, choice matters to the tackler, and taking it away is not ideal, because it may force the tackler to go low when it’s actually better to stay high. That’s why the key priority is to do what is necessary to avoid the head. While in general, this involves being bent or aiming lower, that’s not always the case. But there’s enough rationale to ask this question, so the ida of a trial is intriguing.

There are also trials to reduce line speed (the 50/22 law), because pretty much every coach who was consulted in the above mentioned process said that the focus on speed came at the expense of tackle “integrity” and technique, so if you can reduce speed, then the technique may improve and fewer head contacts will occur. Not to mention that taking speed out of contact makes the tackle inherently safer. So that’s an avenue running in parallel with the technique and height interventions.

So those are on the horizon, but what I’ve explained above is the attempts by everyone to “nudge” behaviour in a direction that makes the sport safer without being radical about it. Of course there are concerns – the tackle is a complex, dynamic event where risk can be transferred, created, swapped, and so it’s possible that one problem is solved, another is created. The plan is to replicate the same study in the future. And in a follow up post, I’ll walk you through the U20 World Championship to describe whether that confirms or refutes the picture I’ve described here.

But hopefully you appreciate that none of this is guesswork, and there’s data and logic behind the desired changes. And a lot of hope that they might turn down the risk of concussion. Early signs are positive, globally, it’s just a matter of monitoring, refining and confirming.

Ross

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