So, @WorldRugby has released guidelines for contact load during training in elite rugby. You can read the full document and a summary infographic here:… I wanted to share brief thoughts on the process & principles behind the guidelines, so here goes...
@WorldRugby First, the need. Research has found that training injury risk (in terms of incidence, or injury risk per 1000 hours) is relatively low, BUT…because training volume is so high, a large number of injuries happen in training. And full contact training has the highest risk. So the
@WorldRugby …need is created by the risk. Plus, cumulative load (including training) is clearly important. Therefore load management principles, just like you’d apply to any training programme, are crucial to reduce injury risk. That’s summarised in the first of the infographics:
The fundamental principle is this: What is the smallest “dose” of contact that achieves the desired result? More than this adds no additional benefit but increases risk, while less fails to prepare players. This is really the crux of the issue (this is true for every sport btw)
So the process was this. First, @worldrugby is really committed to being evidence-based. Problem is, on this matter (how much training is too much?) there is no quality evidence, so it’s more about being “evidence- and expert-guided”. The evidence came from a survey of players
@WorldRugby …around the world (M & W). They provided a ‘benchmark’ for how much contact they did per week, for full contact, controlled contact & set piece training. This is important because next, an expert group of coaches, players, S&C experts, and medics, met to discuss optimal load
The survey results do not create the guidelines, but they do set up what a reasonable expectation is for what elite players currently do, what is needed & what is reasonable in terms of guidelines moving forward. The process is summarised in infographic 2
Now for the ‘meat’. First, the expert group identified four elements that create contact risk. They’re summarised in this infographic. Key is to understand what can be controlled, & how changing any or all of these four changes risk in a session, in search of that optimal dose
Next, of the four, the expert group identified that volume x intensity is the key to load measurement. This is common for load monitoring in sport, by the way. So that creates a tool for measurement, the contact index.
The expert group further identified key principles for contact load. These are captured within three possible PATTERNS for load, but they all obey the following:
1. Two days of full contact load per week, three days “recovery"
2. Zero (or very low) contact load on M and F
It’s within these patterns that the recommended limits per week happen. They are:
- 15 min of full contact
- 40 min of controlled contact
- 40 min of live set piece play

I would encourage anyone interested to read the full document to understand the diffs between them
Then, to head of some criticisms I’ve seen, let me emphasise/clarify the following:
1. The guidelines were not created in a vacuum by lawyers. Look at the names of people involved. If you think these folk don’t understand the sport, submit your CV, because you must be incredible
Second, nobody wants to treat the rugby community like disobedient children, so no, the idea is not to stand there with a stopwatch and issue punishment when the contact time exceeds the recommendations. These are guidelines, basically best practice recommendations from experts
Coaches may want to do more contact training. If the expert recommendations are correct, then that’s a risk they’re taking. And maybe in time, with tech, awareness & education, it will be possible to enforce, rather than advise. But people needn’t be ‘babied’ for change to happen
Then, some more musings. One ‘concern’ (for me, anyway) is that there’s a risk of creating a kind of circular logic by using player feedback to set the contact time limits. This is in a way unavoidable because there’s no data that says “X time increases injury risk by Y percent"
So for now, the only evidence is that of reported time. The expert group also knew this and tried to explore the limits from first principles rather than simply drawing the line near where it already was. The survey was crucial though, because it sets a realistic expectation for
…what is currently being done, and thus what is reasonable to ask to be done in future. I can see a future where contact load is measured much more precisely, using instrumented mouthguards (we have two big studies currently underway on this subject), so that teams can actually
…quantify head & overall contact load, and then maybe a future iteration of these guidelines advises something like “Total load per week should not exceed X impacts above Y g, and no more than 8 fully contested scrums should be performed”. Or something like that. This is a start

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More from @Scienceofsport

18 Aug
@SUE_K47 Yes I saw it. And it’s important that the research be recognised as flawed (in some respects, faulty) & limited. But I don’t see this as the bombshell Roger is claiming. the DSD policy has two components - the evidence around specific events (which is what the paper did so badly
@SUE_K47 …and second, the principle regarding androgenisation in males, not females, that necessitates a separate competition. I think everyone at CAS already knew this about the research - it was discussed at great length there. From the flaws to the theoretical problems. The IAAF even
@SUE_K47 …conceded, at CAS, that there were issues with the research, and nobody claimed it was “conclusive proof” of advantage. So this correction doesn’t actually change much about what was heard by CAS - both sides debated the paper pretty intensely. So I don’t think it’s a ‘bombshell
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4 Aug
@DesiFootyStats It’s different by scale (a lot) and concept. First, scale. Phelps was about 0.2-0.4% better than his rivals. Indeed, he even lost races. His “advantage” was worth about half an arm length. Compared to the male vs female advantage, that’s tiny. M vs F is about 10-12%, so Phelps
@DesiFootyStats …would be about FIVE body lengths ahead of Ledecky or McKeown. The M vs F difference is enormous, way way bigger than anything that exists within males because of long arms or whatever other simplified theory one has for why an athlete wins.

Next, let’s talk concept.
@DesiFootyStats Let’s begin by asking “why do categories exist in sport?” What’s the reason we have a women’s event, or a lightweight boxing title, or age categories etc?

The answer is that we create categories because we want the outcome of a sports event to have meaning and be a way to
Read 11 tweets
2 Aug
Folks, you can't measure the presence of an advantage by whether someone wins or not. It has to be measured relative to self. The final performance is the SUM of base level PLUS advantage. So looking only at the final says nothing about the presence of absence of an advantage.
For instance, if I competed in the Tour de France with a 100W motor in my bike, I clearly have an advantage. But I still wouldn’t win - my base level is too low. In order to surpass the competition, your base level must be close enough to them that your advantage takes you ahead
The same is true if you use a doping analogy. We KNOW doping improves performance, it is an advantage. But a doper doesn’t always win. Because unless the doper is within the % of their rivals that doping improves then by, their base level will not allow them to win an event.
Read 4 tweets
2 Aug
The paradox in action. Illegal advantage in the 400, legal in the 200. The reason this weirdness exists can be traced back to the CAS Chand decision in 2016, and the “narrow” framing of evidence for the DSD policy, but this situation was inevitable. The events are too similar
Ok, brief explanation. In 2016, the policy for DSD athletes covered all events. Chand challenged it, and CAS said they understood the rationale for the policy, but it required evidence. WA were thus mandated to find the evidence. They tried, but did a poorly conceived study that
…looked for an association between T and performance in each event. They found a positive association in the 400m, 400m H & 800m, and actually a negative on in the 100m! But the policy was thus revised to cover those events, plus the 1500m, as it was deemed similar to 800
Read 10 tweets
30 Jul
Mixed 4 x 400m relay heat 1 in Tokyo has just given us a great illustration of sex differences in running (see leg 3 to 4). Based on some discussion here over the last few months, a lot of people need to see this real world illustration. Including, apparently, English commentary
Speaking of the mixed relay, I think it would make the race incredibly exciting if they made teams draw randomly to decide the order of sexes. Imagine a race with some teams going MMFF, some FFMM, some MFFM, or MFMF etc. That race would be suspenseful and hugely unpredictable

Here’s a handy little toolkit for that mixed 4 x 400m final. Top 2 qualifiers (or heat winners) get to select their order. The other 6, you just cut these little strips up, and make the teams draw from a hat. I promise it’ll be super exciting the whole way! 👍🏼
Read 4 tweets
29 Jul
On transgender women & performance advantages. One thought - isn’t it astonishing that given “lots of aspects…physiology & anatomy & the mental side”, that NO female has EVER come within 10% of the best 1000 males?

Or…is this an irrelevant distraction given that BOTH males...
…and females already possess the physiology & mental side necessary to be champions within their respective characteristics? So what is the source of the huge gulf in performance?

This is, in fact, the most direct journey to saying a women’s category is not necessary in sport
That is, if elite performance is a result of "a lot of aspects", we can crown a single “human” champion in all events

But where are women among the top 1000 humans in the world right now? Is it a co-incidence that they never have these aspects?

Or…maybe they’re different?
Read 7 tweets

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