Ross Tucker Profile picture
Sports science, insights, opinion. Sport through X-Ray glasses. One half of The Science of Sport podcast - @sportsscipod
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9 Sep
Let me share a few thoughts on the latest #Semenya development - her appeal rejected by the Swiss Supreme court, World Athletics policy supported (pretty strongly too). We are planning a short pod on this tomorrow too, but here are a few thoughts… (1/…)
First, we’ve spoken a lot about transgender athletes recently. That has many elements to it. This has even more, and it’s really an unsolvable situation. It’s been present for nearly 100 years in sport, some horrendous attempts to manage it, and no clean solution in sight (2/…)
This decision establishes, for now, the policy that requires athletes with hyperandrogenism to lower T in order to compete. But not any hyperandrogenism, and not just any events. It covers only that caused by a selection of DSDs, where a person is 46XY, with testes, and thus (3/
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31 Aug
Last week, I posted a thread addressing a common criticism of transgender athlete policies, namely that they’re based on evidence in non-athletes. Here’s that thread, for a reminder. Today, I want to mull on another common issue raised in objection: (1/)
The objection is this: People argue that because trans women are often smaller, lighter, slower, weaker etc than biological females, it should be fine for them to compete as women. It’s an “overlap argument". Here’s one example of that thinking (this particular poll backfired): Image
The premise of the argument is this:
- Testosterone confers upon males advantages including size, strength, speed, power. This is why women have a separate category;
- If someone identifies as female (trans women), provided they’re not too big, strong, fast, they can compete as W
Read 15 tweets
24 Aug
This has been a common argument in the trans women in rugby debate. People have the idea that unless you *directly* study rugby AND show that TW cause injuries, it can’t be evidence based. Of course it can - there are peer reviewed studies that show two related things (thread)
2/ First, you have so many studies that identify both performance determinants and risk factors for injury in rugby. Dozens of studies identify when injury occurs, and thus what the significant risks for injury are. Similarly, performance is multifactorial but is KNOWN to be...
3/ …significantly influenced by a handful of testable/measurable factors. In fact, these measurable factors are so crucial and “robust" that teams actually have minimum standards for them, and select or drop players based on achieving these targets. They’re not “guesses”.
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24 Aug
@AntiAnja @Lukeyswords @cuthbert_shaw @JohnJMcGivern @WorldRugby We are hearing this argument a lot. People have the idea that unless you directly study rugby AND show that TW are causing more injuries, it can’t be evidence based. But of course, it can. Because there are peer reviewed studies that show two related things. First, you have...
@AntiAnja @Lukeyswords @cuthbert_shaw @JohnJMcGivern @WorldRugby …a ton of studies that identify what causes injury and performance in the sport. You know, based on hundreds of studies, when injuries happen, and how, and so you can identify the significant risks for injury and the determinants of performance. The performance variables are...
@AntiAnja @Lukeyswords @cuthbert_shaw @JohnJMcGivern @WorldRugby …so robust that teams actually have minimum standards for them, and select or drop players based on achieving these targets. Then second, you have a host of peer reviewed studies that have examined what the biological differences are between M and F, and what this means for
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29 Jul
@bloodandmud @smash_rugby @CarolineLayt @SquidgeRugby @KirstiMiller30 @VeritySmith19 @CardiffLions Hi Lee. Heard your discussion on the latest pod, and appreciate the views raised (though I don’t agree with some of the criticisms of the process). regarding the science, the principle or conceptual approach to the issue is very much the same as it was for head injuries. (1/)
@bloodandmud @smash_rugby @CarolineLayt @SquidgeRugby @KirstiMiller30 @VeritySmith19 @CardiffLions That approach is a classic “public health model” where the risk is first identified, then risk factors are assessed, and then attempts are made to mitigate, reduce or avoid those risk factors altogether. I’m know you’re familiar with how this played out in the concussion space
@bloodandmud @smash_rugby @CarolineLayt @SquidgeRugby @KirstiMiller30 @VeritySmith19 @CardiffLions In this area, the same recognition of risk was raised. What you guys discussed on the pod, which wasn’t entirely true, is that there is ONE anecdote (the deckchairs) that raised this concern. There were actually multiple concerns raised. So that was part of it - the sport was
Read 38 tweets
29 Jun
Something keeps coming up in the discussions about women’s sport, fairness and advantages for transwomen. It’s that there is an overlap in the physiology affecting performance between males & females, which some say makes arguments about unfairness irrelevant. Here’s a thread (1/
First, the start point is saying that physiological attributes that drive performance overlap between M & F. This is definitely true - many women are stronger, faster, more powerful, muscular, leaner etc, than many men. Nobody would dispute this - just join a race to find out (2/
Next, this observation - a spectrum for the secondary sex characteristics - is used to argue against a sex binary, which is disingenuous. They’re different things. But it evolves into saying that because there is overlap and because sport is all about “natural advantages”, the...
Read 17 tweets
13 May
Here's an important paper in the transathlete debate, by @TLexercise & @FondOfBeetles. They ask whether male performance advantages are removed after testosterone suppression? (as required by many sports policies for transwomen to compete) My thoughts (1/
preprints.org/manuscript/202…
To give the answer upfront, they answer the question with a very strong “no”, as per this section in the conclusion (the yellow bit), with the implication highlighted green. To reach this point, they follow a pretty simple path, which i want to summarise briefly if I can:
The argument is set up and developed in 3 steps:
1. What are the biological differences between males & females?
2. What do these biological differences do for performance differences between males and females?
3. What does testosterone reduction to do to 1, and thus 2?
Read 23 tweets
15 Apr
So, yesterday I shared with you a presentation I made on #immune function & exercise, and then on detraining & fitness during #lockdown. How much, how fast, how to prevent etc? Here’s the link again to watch it n full, and a short thread to summarise: (1/)
(2/) To begin, there are a few times in exercise physiology (& other domains, I’m sure) where you hear about a “J-Curve” model.
Exercise & immune function is a classic J-Curve: Too little = bad, too much = bad, but in between = lower infection risk. Fitness is a health benefit
(3/) Then you have the “Open Window hypothesis”, which is to the J-curve what Bonnie was to Clyde. Idea is that there’s a window after intense and/or prolonged exercise where you’re more vulnerable to infection. Diagram shows changes from hard (marathon) & easy (walk) exercise
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16 Mar
2 weeks ago I posted the below about @worldrugby's Transgender meeting, where various experts were invited to present to & discuss the issue to a policy group. WR committed to making the presentations public, so here they are, as promised, plus an update:
Here are all the presentations that were given over the course of the two days: playerwelfare.worldrugby.org/?subsection=84

They are arranged in order, so it goes science, medical, legal/risk, social and then ethical domains. You can download and see what each speaker presented. (2/)
Here’s the agenda, if you want to see who spoke, and in which session. The next steps are to formulate the policy/guideline based on all evidence, plus a few more consultations arising out of that meeting, and then it moves through the ‘system’ for approval/discussion/change etc
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27 Feb
The #transgender athlete in sport meeting organized by @WorldRugby is now done. I want to share the PROCESS (*not the outcomes, at least not yet) with you, explain why it was designed that way, and what the next steps will be. Here are all the delegates, and this is a thread (1/)
(2/) The process followed was designed to be comprehensive, in-depth, transparent, inclusive and rigorous. We set up 3 distinct groups. First, a policy-group consisting of WR-linked people who would make recommendations to World Rugby on how to proceed. Think of them as “judges"
(3/) This policy-group was chaired by the amazing Dr Araba Chintoh (psychiatrist & former Canada international). It had on it 2 sports physicians, a physiologist, a lawyer, head of women’s rugby, head of Technical services, and a women’s player
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5 Feb
When you give engineers 40mm of space to work in, and say that it’s okay (& now necessary) to change the physiological input-output relationship, you make controversy and uncertainty (who knows what % improvement this gives, and is it the same for all? No) part of the sport.
By the way, don’t bother asking how this shoe is legal, because the Emperor’s Clothes of tech regulation last Friday made it clear that all companies SHOULD do this. Also, at this point, it’s more likely that the regulations are compliant with the shoe than the other way around
Aside from obvious issues of equipment parity and the ability of companies to bridge the gap (as they now must), one of the biggest problems I have is that the more advanced we get, the greater the potential gain, the larger the gap between responders & non-responders becomes
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15 Nov 19
(very short thread & some links incoming): It’s been a week where two stories - Cain/Salazar & Freeman’s GMC hearing - pulled back the curtain on what happens in elite sport when perverse incentives (& sometimes people) meet pathological environments. These are lighthouse moments
While specifics differ (superficially, eating disorders vs doping), I think they share a few “source" elements:
1) Imbalance of power - created because there’s “only one way to win”, so there are ‘gatekeepers’ who make or break futures. They assume positions of “idolisation” &
…absolute authority. In the absence of any checks & balances, there’s no accountability. One thing that struck me about the Salazar thing was that he’d go with Cain to the doctor & drive the medical treatment. Everything channeled through one person. It’s crazy. No beneficence
Read 17 tweets
7 Nov 19
@thedeadballarea @JT_Sports123 @RugbyInsideLine @timoconnorbl Few points in response - to the initial question, “Do PED investigations go deeper than just test & catch?”. Not really because nobody is looking. Paul Kimmage has done some - he got testimonies from players including Pienaar & Benezech about pain killer use, but few others have
@thedeadballarea @JT_Sports123 @RugbyInsideLine @timoconnorbl …thrown themselves into the kind of investigative work that would reveal more. Lack of incentive/will, I think. Second, I don’t think it’s individuals in isolation, but it also doesn’t need to be this “centrally controlled, top-down, masterminded system” like we’ve been shown by
@thedeadballarea @JT_Sports123 @RugbyInsideLine @timoconnorbl …cases like Russia, USPS etc. Even in cycling, Syed for instance often argues that it can’t be systematic, thus it can’t be happening, which is stupid. It can still be “centrally provided”, or facilitated, and diffuse and up to the individual. So for instance, in a school team,
Read 7 tweets
22 Oct 19
I’ve lost count of how many times this argument is made, but it’s as ridiculous every time. Biological sex, not identity, is the reason for separation because it’s the most powerful performance determinant. Other physiological attributes differ enormously, both in scale & concept
Right or wrong, we don’t ‘protect’ short-legged, slow-twitch, small-hearted humans in any sport. We DO protect lighter mass in contact sports (for good reasons), and Paralympic sport has categories to create meaning through fairness. Separation by biological sex creates meaning
So that’s why biological males are "singled out”. Not doing so removes meaning of sport for those who don’t stand to benefit from androgen advantages. Until evidence emerges that hormone suppression for 12 months (or whatever duration) removes those, the status quo must remain.
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12 Oct 19
Earlier today I posted a version of this going the other way, showing what a 2:03:00 would become with a performance boost of X. Here it is the other way - if the economy advantage of shoes is X, then the performance benefit = 0.65X, so what does a 1:59:40 equate to? Pick a line
You can of course pick the bottom one - make the advantage zero, that’s cool. If so, then whatever improvement happened today was pacing/drafting/course related. If you set it at the lab, then today offered very little. At half, it’s Berlin 2018 with a small boost. Who knows?
Where we are now was entirely predictable in 2016 - the integrity of performances is impossible to evaluate, because the exact performance advantage is unknowable. All we know is that lab studies show it to be massive and universal (which is unprecedented). So guess its size
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27 Sep 19
#Doha2019 World Champs starts tonight! Our NEW podcast sets the scene with a focus on the physiology & impact of the heat, & other likely themes (doping, stars, races to watch): podcasts.apple.com/za/podcast/the… Available on all major pod platforms. We’ll do event analysis next week!
Speaking of podcast, here’s a little ‘aperitif’ of our podcast discussion. Right now, in Doha, these are the conditions. The women’s marathon starts at 11.59pm in Doha. So 32C, very little wind, humidity 74%, feels like 42C. Terrific fun…performance-wise, here’s some thoughts...
Running produces heat - the body allows heat storage, and our temp climbs from resting 37C into the 39s, approaching 40C. Eventually though, a critical hyperthermia is reached. In lab studies, it’s at about 40C. Elites in races can probably go higher. But eventually, ‘lights out'
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30 Aug 19
Let’s briefly talk about some background on #Dyanti and doping. A short thread. Specifcally, we are looking at metandienone, methyltestosterone and LGD-4033, which are the substances confirmed as found in his A & B samples, for which he’s now charged: sport24.co.za/Rugby/Springbo… (1/)
First, let’s orientate ourselves about what we’re dealing with. All 3 those substances are in Class S1, in substances & methods prohibited at all times. S1 is anabolic agents, Testosterone, Stanozol, DHEA the most famous of them. I’ve highlighted in yellow the 3 in Dyanti’s case
Anabolic agents (aka androgenic agents) are responsible for “building up". Muscle, especially. Androgenic = “male making”, so again, muscle growth & repair, improved recovery, greater strength gains when training, injury repair. Hence their placement on the banned list.
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27 Aug 19
On male vs female performance differences: we often refer to a 10%-12% male advantage in running events. But what of power/strength sports? Inspired by @mar_vickers, I plotted weightlifting’s Olympic records for men & women. Men are 26% to 39% stronger EVEN CORRECTED FOR MASS
So to explain - the left graph shows total weight lifted (snatch + C&J), right is where I’ve expressed the OR as weight lifted per kg body mass. Open circles are estimates to allow “direct” comparisons at a given men’s weight class - gap is 26% to 39%, much larger than running
Implication is that if testosterone reduction is to “equalise” performance for the sake of the integrity of women’s sport (weightlifting in this instance, as a proxy for strength/power), it must “knock out” about 30% of any advantage as a result of “biological sex” (not mass)
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8 Aug 19
Cricket Australia announces guidelines for transgender inclusion (will ask for T levels under 10nM for 12 months). I get that sport is facing a real dilemma, the societal pressure to be inclusive. But in sport, it DOES make sense to exclude some people from certain categories
And one of those categories that depends on ‘exclusion’ is women’s sport. This is because men & women are separated because the performance gap created by BIOLOGICAL (that is, sex) differences is so enormous that without “exclusion”, women’s sport loses a big part of its meaning
Other examples are age categories, weight categories & categories for disability in the Paralympics. For these categories to have integrity (to protect their participants for both safety and competition), the exclusion of people “above” them is actually crucial, not arbitrary
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29 Jul 19
@pauldimeo2 @clarelobster @stevechapman65 Yeah, so which test is going to pick up an athlete who intelligently micro-doses to get Hb up from say 14.6 to 14.8 (within normal variation), or who recovers 5% better (“I’m just sleeping amazingly well, coach”), and thus improves by 3% to go from 6th to 1st? No way.
@pauldimeo2 @clarelobster @stevechapman65 So to be precise, there are many staff who *COULD* notice any changes, but unless that person is doping with a blunt instrument like an axe, it’s not happening. It’s a scalpel these days. Five scalpels, 5 bio-plausible excuses - I’m sleeping well, eating better, lost weight etc.
@pauldimeo2 @clarelobster @stevechapman65 So in my daily feedback report, thanks to my EPO & T use, & my friendly doping doctor, my recovery is 9 / 10, instead of a previous 7 or 8. I say it’s early bed times, ice baths & no food after 8pm. Everyone monitoring it goes “Shit, Ross is doing great, he’s really disciplined"
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27 Jun 19
I’ve arrived in London for the World Rugby Law Review group meeting. A key role of laws is player welfare/injury prevention, so let me try give a run down of the key factors regarding injury - what, when, how - in a short thread ‘tutorial’ (1/)
First, we have to define an injury, because it could range from a ‘medical complaint’ to hospitalisation. Most of the studies (all of which are published/peer-reviewed) use a 1-day time loss - the player can’t play for a day. Then from this we can work out ‘incidence’ (or volume)
“Incidence” is injuries per unit exposure. So you can say it as injuries per 1000 hrs (the best way). Or per match. Or minutes between injuries etc. In the data I’ll walk you through, there are 943 matches from 4 competitions, and the average is 86/1000 hours, or 3.4 per match.
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