Save female sports evidence thread

[Helleofabore]

I am conscious that the Break it Down for me thread is nearly full. I am therefore hoping that this thread can be an archive thread just for the sports evidence that we can all access and refer to. Now that MNHQ has given us the option for saving threads so we can find them easily, I figure it is a good time.

Please post studies, papers, media articles that pull together references, or informative articles, tweets, videos. Just on sport, the latest policies around sport.

I don't want to be the thread police, but ask that we keep this free of discussion. Can I ask that if you want to discuss something you see here, you start a thread to do so?

Because I would like this to be just information stashed so that people can find the links easily so they also know where to start. And getting into discussion on this thread will mean it will fill up.

Thanks.

CYCLING POLICY FOR TRANSGENDER ATHLETES - JUNE 2022

assets.ctfassets.net/761l7gh5x5an/4EopPD4g1xjd0aNct2SCPt/8987aec0f5a3bc020411dd2bf8cfea7e/Transgender_athletes_in_cycling_June_2022.pdf

The UCI document regarding the regulations they have brought in.

T to be 2.5 nmol / 2 years

ATHLETES OPINIONS ON MALE INCLUSION IN FEMALE SPORTS - BRITISH TRIATHALON

www.theguardian.com/sport/2022/jul/06/british-triathlon-creates-open-category-for-transgender-athletes-to-compete-at-all-levels

The significance here is that British Triathlon polled members and 80% supported female only category.

Here is the rundown of the policy by Sean Ingle, 2022

Triathlon has become the first sport in the UK to ban transgender athletes from racing in the female category at elite and grassroots level after deciding that “fairness of competition is paramount”.

Under British Triathlon’s new policy, which kicks in on 1 January 2023, transgender athletes over the age of 12 will now have to compete in an “open category” for “all individuals including male, transgender and those non-binary who were male sex at birth”.

A second “female category” will apply only “for those who are the female sex at birth”. The policy will apply to any race that is timed or has prizes

Link to policy

www.britishtriathlon.org/britain/documents/about/edi/transgender-policy-effective-from-01-jan-2023.pdf

ONE OF THE Q-ANGLE DIAGRAMS & A POLL

If you believe in fair competition, Emily Bridges should not be racing Laura Kenny

Owen Slot, The Times, 29th March 2022

https://archive.is/u4oSa

www.thetimes.co.uk/article/3081c8c0-af7c-11ec-8b8c-0207c0fd6104?shareToken=dfc4c5b36b407a8e0ccc2133e718b121

"Biomechanically, though, she still retains distinct advantages. The athletes she will be competing against have naturally wider hips. For the purposes of powering a bicycle, the crucial element here is that they will have a wider angle between the hips and the knees — this means their quads do not work so efficiently in transferring power."

There is also a poll

Should transgender athletes be allowed to compete with women?

(also not necessarily clear as it doesn't clarify transitioned females)

7 131 votes with 98% saying no

The above diagram is an excellent explainer also of why posters refer to looking at the knees of athletes.

Female knees are usually quite different to male knees.

COMPETITIVE ADVANTAGE / PHELPS GAMBIT / PHELPS ARGUMENT

Here is a good explanation. It has links to relevant information embedded so it is best to see it on twitter.

https://x.com/FondOfBeetles/status/1374331296143581186

But here is some of it:

Phelps' wingspan:height ratio is 1.04. It's straightforward to find other males with the same ratio who are slower than Phelps in some strokes, but who are faster in others. e.g. Matt Grevers. Ratio 1.04, slower freestyle than Phelps, faster backstroker than Phelps. Interestingly, despite the same wingspan:height ratio, he's, in absolute numbers, generally bigger than Phelps.

What you never find is a female with the same wingspan:height ratio who is there or thereabouts compared with Phelps. Missy Franklin has a ratio of 1.03, yet is over 10% slower than Phelps.

It's almost like wingspan:height ratio isn't discriminatory in the pool. Even absolute wingspan or absolute height isn't discriminatory.

And there's a very simple reason. When you select, on national or international levels, for athletes that are good in a particular discipline, you will tend to pull through an entire group who all share the general advantage (in this case, swimmers are tall with long arms). Phelps, with height (not the tallest) and wingspan (not the widest, nor the biggest ratio) is, for sure, built to be a better swimmer than almost every other person in the world. But his body shape is not particularly extraordinary within that group of competitive swimmers.

To argue that his advantage is extraordinary within the entire male population, sure. Well, I wouldn't go with unfair, but's a real advantage. But he doesn't race against the male population. He races against other males who are likely to share the same advantage.

This is why The Phelps Gambit (trademark pending) is nonsense, and immediately flags that the person asserting it has read numerous MSM stories about the glorious physique of Phelps (and he was glorious, absolutely), without applying any deeper analysis.

Men can have long arms. Women can have long arms. Men with long arms are better swimmers than women with long arms.

COMPETITIVE ADVANTAGE / PHELPS GAMBIT / PHELPS ARGUMENT

Here is another explanation of why the Phelps Gambit is weak.

https://x.com/Scienceofsport/status/1820462042765001041

Ross Tucker
5 August 2024

Yeah, poor old Phelps became the poster child for this illogical argument that his advantages are the same as those of males. I'll try to explain why this is such poor thinking. First, Phelps' advantages are not category-crossing. That is, there is no category for short arms, and there is no category for small feet, or high lactate producers etc. So we have decided, for better or worse, not to create a category for people without Attribute X. And thus, when a person has X, they shouldn't be excluded, so there's no basis to disqualify Phelps.

Now, one could have a debate over whether we SHOULD think about creating a category for small feet or short arms. If we did this, then Phelps' supposed advantages would become 'outside of category', and we'd say that he's not allowed to swim in the protected category, right?

But we don't need to do this, because the advantages that he has are tiny compared to what male advantage does to performance. Phelps wins by 0.5%. Males win by 12% (compared to females). By scale, then, these advantages are orders of magnitude different.

It's also a massive oversimplification to say that Phelps won because his arms are long or that he produces less lactate. They're daft, incorrect attributions anyway. And finally, females also have some of these advantages - there are women who produce less lactate, or have long arms.

They don't make up for the absence of male advantage. So they're totally different situations. Fundamentally, what sport is trying to reward are those exceptional individuals within categories. We actually celebrate these advantages, they make sport what it is, no?

But we need to rule out some other advantages - size/mass in boxing, age in all sport - because otherwise the things that do NOT matter overwhelm the things that do. Phelps physiology matters - it's why he wins gold medals. Katie Ledecky, though, also has physiology that deserves gold.

It's just she doesn't have male advantage as well. And that's the point - "as well". They are equally great swimmers, but within their categories. The only way around this is to say that we should create a category because Advantage X is so large it also overwhelms the result.

But it doesn't - as mentioned, by scale, what Phelps has over males is tiny compared to what males have over females. Put another way - the fastest swimmer with small feet or shorter arms (whatever that means) is not beaten by thousands of longer armed, bigger footed swimmers!

So I hope I've not laboured that or explained it clumsily. To sum up, Phelps is a bad counter point. So is height in basketball (there's no "short people NBA, only 180cm or under" category).

Rather think age, weight and disability class, and ask if the attribute, X, devalues the things we actually want to reward, or whether it's part of it. Phelps' advantages are part of the excellence. Male advantage is not - being male is NOT a talent, and as such, shouldn't be part of the mix. What Phelps has, those are different.

COMPETITIVE ADVANTAGE - A REALLY QUICK ONE FROM DR HILTON

"Having male biology is not simply another type of advantage athletes have, it’s an advantage we have created categories around. We all seem to agree that having a woman’s category is desirable and necessary, we all know it’s because men are, as a group, bigger and stronger etc, and that without protection from male advantage, women wouldn’t win in athletics sports. So it’s perfectly coherent to argue that anyone with this type of advantage - male advantage - is ineligible for the category designed to exclude it."

11th August 2024

https://x.com/FondOfBeetles/status/1822649897918861380

SEX TESTING THEORY FROM DR EMMA HILTON

There are some great graphics on these tweets if you go to them.

https://threadreaderapp.com/thread/1821903707635618276.html

OK, science geeks. Sex testing and sport.

There are many people spreading misinformation about the reliability of sex testing, repeating arguments made for its abolition some 25 years ago.

I don’t know if they have noticed that we’ve undergone something of a genetics revolution over the past few decades

So let’s look at some chromosomes.

Historically, chromosomes were analysed by adding a chemical dye to cells and looking at their shape and size. Given that most animals have two copies of each chromosome, the pairs could be lined up by matching their shape and size.

These are chromosomes stained with a dye called hemotoxylin. I still use this dye in the lab today.

Nettie Stevens discovered sex chromosomes in the early 1900s, after noting that female worms had twenty big chromosomes while male worms had nineteen big chromosomes and plus a small one.

Further, she noted that Worm Sperm either had ten big chromosomes or nine big chromosomes plus a small chromosome.

She reasoned that the small chromosome carried by some sperm makes male babies, while the sperm carrying the tenth big chromosome made female babies.

Brilliant woman, but her discoveries were overshadowed by the male scientists of the era, of course.

In the ensuing decades, improvements in sample preparation, the types of dyes used, and the optics of looking at tiny samples, meant scientists could start to score chromosomes not just by size and shape, but by the pattern the dyes made on each pair of chromosomes. This made the tedious work of matching up pairs much easier.

In the 1940s, Murray Barr discovered a tightly-packed ball of chromosome material hanging around the edges of the female cell nucleus. He named this the Barr Body.

He also developed, in the 1950s, the cheek swab as a way of sampling human chromosomes.

In the 1960s, Mary Lyon discovered that in female mammals, who have two copies of the X chromosome, one of those Xs is shut down. We now know that this process is needed to regulate the amount of active X chromosome genes a cell can handle. Males, with only one X, don’t need to do this.

The tightly-packed ball of chromosome material discovered in the 1940s - the Barr body - is this inactivated X chromosome. The process of packing the X ball is called Lyonization. It is this process of shutting down one X chromosome that gives us beautiful (female) lion-like creatures.

The process is also important in understanding how sex-linked genetic diseases affect females differently. Including in my own research.

It was soon realised that looking for Barr bodies - which give a very intense and obvious dye signal – was a quick way of checking what sex an animal was.

Including, in 1968, human animals playing female sport.

Females with two Xs have this bright dye spot, males with only one X don’t. Simple, right?

But some males have an extra X (XXY, Klinefelter Syndrome) and they pack their second X down, just like females, giving a positive signal on the Barr body test. And some females only have one X (X0, Turner Syndrome) and no Barr body.

The Barr body test could tell you about second or extra X chromosomes, but this wasn’t the best way to understand the sex of the person.

In 1992, sex testing sport switched to the more accurate method of trying to find a gene on the Y chromosome called SRY. This gene is considered a master switch in male development.

The test was done in a chemical reaction (the polymerase chain reaction, for the geeks) to rapidly replicate large amounts of the SRY gene from a DNA sample, which could then be detected by routine DNA gel analysis. If SRY isn’t in the sample, you don’t get any replication.

Can anyone take a guess at the sex of the fetus in the image below?

But, of course, some males may have the SRY gene but they do not develop as a healthy male. That is, they have a disorder of sex development.

In 1999, sex testing was abolished, given the unusual results popping in the female athletes, the potential for trauma in those athletes, and the prevailing opinion that having a male XY DSD probably didn’t matter in female sport.
Of course, today, that prevailing opinion from over two decades ago has been overturned. We understand more about sports performance, male advantage, and what anatomical features contribute to it.

We have far easier and cheaper ways of looking at chromosomes and DNA, and we have stronger ethical frameworks regarding genetic testing. The “bad old days” that the International Olympic Committee evoke to obstruct sex testing that would protect the female category is a red herring.
Today, testing for sex is routine. Our sampling is better, and we can find sex chromosomes from really small amounts of suboptimal material. As many mother’s will know, we can find fetal sex chromosomes from Mum’s blood sample. Our dyes are better. Our imaging is better.

Forget dyes that showed us size and shape, forget dyes that give us patterns of bands, and start looking at light-emitting molecular dyes that bond to specific genes on specific chromosomes instead (and light up two green Xs and one red SRY). Look at how a computer can read those signals.

I mean, even this Beetle Lady can do it ;)

The flashes of red light you see? That’s from my published research, flagging an X chromosome gene that underpins a sex-linked genetic disease that is lethal in male fetuses.

Forget those gels of a single rapidly replicated gene and start thinking about putting those light-emitting flags into the chemical reaction instead. The more replication, the brighter the light signal. And why not add multiple genes to the same process. And trust me, a light detector can see things your eye cannot.

See those differently coloured lines? They are different pieces of DNA being rapidly replicated in the same sample.

And why stop at whether a gene is there or not? Why not look at the sequence of a gene? Gone are the painstaking days of moving down a radioactive image with a ruler. I can get a computer to read a gene sequence for me in a few days for a few pounds. And even this is by a fairly cheap and old-fashioned method.

In 2003, the Human Genome Project was completed. This was first full sequencing of all the genes (plus everything else in between) on all the chromosomes in a human being.

It took a global effort 13 years to complete, and cost $billions.

Today, not so much. We can sequence the entire gene set of a human being in a matter of weeks for $hundreds.

The IOC is fervently hoping that renewed calls for sex testing sport quietly go away.

Ironically, they probably will. Because now on the horizon of this genetic revolution is, quite simply, standard screening of whole genomes in newborn babies.

No longer will we have to trust a midwife to take a guess.

Tweets are here.

https://x.com/FondOfBeetles/status/1821903707635618276

RE: THEY DON'T ALWAYS WIN - WHY THIS LOGIC SIMPLY DOESN'T WORK

(these are my thoughts by the way)

But they didn't win', 'they have been beaten', what does it matter, type arguments really show a complete lack of understanding about competitive advantage.

The male athletes losing are losing because they when you considered their physical advantages, if they were elite level male athletes at the same level of peak performance as the female people that they were losing against, they would not have lost. They are not at any where near the level of exceptionality of the female athletes they are competing against.

In many instances, their performance rates as mediocre when compared to male athlete peak performance.

To be very clear, if the male athletes losing to those exceptional female athletes were as good and as fit and performing at their full potential as those elite athletes, they would have won.

In fact, several male athletes are competing in female events and setting records that female people may never break. Those male athletes are in almost comparable performance level as the exceptional female athletes, but their physical advantage is coming into play, so to speak.

Consider the physical advantage to constitute x% performance advantage over all. To achieve the same level of exceptionality of the female athletes, their performance will = peak female athlete performance + x%. Hence setting records that may not be broken.

If the female athletes are beating the male athletes and those athletes have male pubertal advantage, then they simply are not as good as the female athlete. In fact, if those male athletes with x% pubertal advantage tied with the exceptional female athlete, then by comparison, the female athlete is better.

So this point too is irrelevant for competition. But. Not for safety.

Using Boxing as an example:

If you are supporting male inclusion based on 'they don't always win',
what you are supporting can, in effect, be very dangerous for female athletes. For instance in boxing, this is due to male people have on average 160+% more punch power than female people (that is not athletes, that is just the general population) and many other advantages. In fact, part of the punch power is derived from skeletal leverage that males have to give this power that female people do not have. And bone mass and density that is greater in male people than female people.

https://pubmed.ncbi.nlm.nih.gov/33289906/

This above is the review of 13 studies from Dr Emma Hilton and Tommy Lundberg and it shows these advantages, if anyone wishes to check for themselves.

To be clear. This bone difference means stronger bones!

Female people have been proven to have bones that are more prone to breakage, particularly in the face. And they are more prone to concussion and brain damage due to their more delicate brain fibres. This has been studied and is now shaping Rugby guidelines for female participation, as an example.

Rugby concussion: Swansea University study into protecting women https://www.bbc.co.uk/news/uk-wales-51434749

To those who use the 'but they didn't win' what do you believe will happen to a female with those more delicate bones and brain fibres when hit with punches that are 160+% harder than other female boxers?

A SOLUTION TO PUT TO IOC REGARDING SEX TESTING

and it is good for a historical perspective too.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/sms.14715

Fair and Safe Eligibility Criteria for Women’s Sport.

10 August 2024

Ross Tucker, Emma N. Hilton, Kerry McGawley, Noel Pollock, Grégoire P. Millets, Oyvind Sandbakke, Glyn Howatson, Gregory A. Brown, Lara A. Carlson, Mark A. Chen, Neil Heron, Christopher Kirk, Marie H. Murphy, Jamie Pringle, Andrew Richardson, Jordan Santos-Concejero, Ask Vest Christiansen, Carwyn Jones, Juan-Manuel Alonso, Rebecca Robinson, Nigel Jones, Mathew Wilson, Michael G. Parker, Arabah Chintoh, Sandra Hunter, Jonathon W. Senefeld, Mary I. O'Connor, Michael Joyner, Eva M. Carneiro, Cathy Devine, Jon Pike, Tommy R Lundberg.

During press conferences at the 2024 Olympic Games, the International Olympic Committee (IOC) invited solutions to address eligibility for women's sport. We take this opportunity to propose our solution, which includes: (a) recognizing that female sport that excludes all male advantage is necessary for female inclusion; (b) recognizing that exclusion from female sport should be based on the presence of any male development, rather than current testosterone levels, (c) not privileging legal "passport" sex or gender identity for inclusion into female sport; and (d) accepting that sport must have means of testing eligibility to fulfill the category purpose.

Historically, administering sex-based eligibility testing has been controversial, mainly due to failures in protecting athlete con-sent, dignity, and confidentiality. As early as the 1950s, eligibility was based on visual inspection of entrants into women's sport. In 1968, these "nude parades" were replaced by more discreet molecular methods including sex chromosome screening, and later by the more specific and sensitive test for the presence of Y chromosome genetic material. However, mandatory sex verification was abolished in 1999. Among concerns at the time was the risk that sport would discover that entrants in female events had an XY difference of sex development (DSD), and that the potential for traumatization and stigmatization of these athletes was not justified, given the prevailing understanding that such athletes are not advantaged in the female category.

Today, 25 years later, there is ample evidence that biological sex is a crucial differentiator in ensuring fairness and influencing safety for female athletes. The participation of male-born competitors (e.g., transgender women) and athletes with certain XY DSDs in female sport is a growing concern. These athletes experience male-typical development from testes producing tes-tosterone, with resultant physiological differences creating athletic advantages and safety risks, even in athletes with XY DSDs who might have been observed as female at birth.

The ethical failures of sports federations in the past cannot be allowed to obstruct accessible solutions to such an important issue in women's sport. The ethical framework that governs modern genetic testing is thorough and, importantly to overcome the shortcomings of the past, it emphasizes individual consent, confidentiality, and dignity. Current technology enables a screening procedure for "sports sex" that involves a simple cheek swab to determine sex chromosomes. This screen can be performed reliably and quickly and should be done in duplicate to ensure reliable results.

The results of this sex chromosome screening should be used to indicate the need for follow-up tests as part of standard medical care, including counseling and psychological support as part of the ongoing duty of care to the athlete. This will permit greater understanding of a potential medical condition, but also allow for an evidence-based assessment of male advantage in sport. However, to preserve confidentiality and dignity, athletes must be screened early-perhaps when they first register in the female category in an affiliated competition and before they are thrust into the global spotlight. This would prevent the individual targeting and unsolicited public scrutiny that has occurred numerous times, most recently in the 2024 Olympic Games. An early, cohort-wide approach that treats all participants equally is overwhelmingly preferable to the current approach that invites targeted testing based on allegation, suspicion, subjective assessment, and bias. Despite the potential for unexpected outcomes, a survey of female athletes after the Atlanta 1996 Olympics revealed that 82% supported sex testing, with only 6% reporting discomfort about the test protocol. Nearly three decades later, we should revisit and respect the female athlete's voice.

It is crucial that sports federations in sex-affected sports are empowered to protect female athletes and ensure fair competition. At least one major international federation (World Aquatics) is explicit in that the eligibility criteria include genetic sex screen-ing, and more federations should consider this addition to eligibility criteria. Rather than "policing female bodies," screening followed by comprehensive follow-up in the rare cases that require extra consideration, with emphasis on the duty of care to every athlete, will ensure preservation of the female category for fair and safe sport.

This paper has some interesting points to consider. As he says, further research is needed for puberty blocked males and children's sports and grassroots. However, he also questions whether it is important to segregate children's sports by sex and grassroots. Of course, he is not a sports scientist but provides some really excellent information about human bodies.

From David Handelsman

https://academic.oup.com/edrv/advance-article/doi/10.1210/endrev/bnae013/7641481?login=false

There is a good diagram showing the stages of genital development and 5ARD & CAIS here as well.

Essential Points

“A definition of the term sport sex is proposed based on an individual's experience of male puberty integrating related physiological factors such as male birth sex, the presence of a testis, and adult male circulating testosterone levels.“

“Male puberty involves a 20- to 30-fold increase in testosterone production over that prevailing in children and women at any age, creating the postpubertal male physical advantages of sex differences in athletic performance through the androgen-dependent uplift forming larger and stronger muscles and bone, more powerful cardiorespiratory function, and higher hemoglobin.“

“Physiological mechanisms of the sex differences in performance may involve muscle memory and the effects of neonatal minipuberty, but alternative explanations claiming effects of GH or an unspecified Y chromosome gene are not credible.“

“While many genetic factors contribute to sporting success, the genetic mutations creating 46XY DSDs defeat the sex classification of sport and are incompatible with fair play in elite individual competitions for the vast majority of non-DSD, non-transgender females. The degree to which sustained complete testosterone suppression eliminates the legacy advantages of male puberty remains uncertain and difficult to evaluate decisively.“

“As a result, traditionally elite individual sports where success depends on power, speed, or endurance are classified into male and female events aiming to create a protected female category allowing women to achieve fame and fortune from success that competing against men would deny.“

“Participation in elite female sports of unmodified transgender (male-to-female) women or 46XY disorders of sexual differentiation in elite female events represents male-bodied athletes using unfair postpubertal physical advantages and is category-defeating for the binary sex classification of sport.“

“Recreational, community, and junior (<12 years old) sports, as well as sports not reliant on physical prowess, may not need a sex classification based on male physical advantages and could operate fairly with an open category.“

“The optimal management in team sport participation of transgender and 46XY DSD individuals is a complex and still unresolved issue depending on the relevant team skills and contribution of any single individual to team success.“

Why males with DSDs where there is virilisation and those males with transgender identities should be considered the same. Ie. Males with DSDs where there is virilisations is not a ‘different issue’ at all as some people claim. Those claims are then used as a silencing tactic.

“These physiological issues of the 46 XY DSD individuals have important ramifications for male-to-female (M2F) transgender individuals in relation to elite sports competition. While neither condition involves deliberate cheating, when unmodified by any testosterone suppressive treatment after completing a male puberty, they both provide the same unfair male physical advantage over all other female athletes as would a non-transgender, non-DSD male.”

An interesting insight into why ‘gender’ is not useful for sports categories.

“The subjective nature of gender identity, which can only be verified by asking the individual, with its potential for volitional change at any time, means that no fixed, invariant gender can be ascribed to individuals. As such, gender cannot form a sound durable objective basis for defining sport sex. Hence, a previous proposal to define “athletic gender” as a means to stratify elite athletic events would be unable to provide consistent objective classifications over different times or events including even within the same competition.”

Interesting point on the hypothesis of muscle memory

“An important amplifier of androgen effects on muscle is the concept of muscle memory arising from the innovative experiments of Gundersen. He first showed in rodents that myonuclei created during androgen- or exercise-induced muscle hypertrophy are not lost when the androgen or exercise stimulus is withdrawn. Furthermore, the residual expanded pool of myonuclei enhance muscle functional responses to subsequent training or androgen exposure. This makes the permanence of myonuclear expansion a pivotal factor in the muscle memory mechanism with relevance to short-term androgen doping and longer-term androgen exposure in individuals who are transgender and XY DSD. Nevertheless, achieving proof (or refutation) of this concept in humans is a formidable challenge due to the practical constraints on decisive but ethical human investigation.”

And

“Ultimately, further rigorous evidence is required to confirm this important hypothesis in humans. If true in humans, the muscle memory hypothesis has many important implications. By explaining the durable uplift in muscle function arising from the dramatic increase in circulating testosterone during male puberty, it forms a key contribution to the sex difference in athletic performance. It also suggests that androgen doping may have lasting effects for many years, if not indefinitely, thereby raising questions about the adequacy of the present maximum 4-year suspension period for androgen doping under the WADA Code.”

And

“Finally, if this mechanism is confirmed in humans, testosterone effects on muscle memory among those who have completed male puberty casts doubt over whether transgender women or androgen-sensitive 46XY DSD individuals could compete fairly in elite female events.”

Forgot to add this diagram.

This diagram shows the degree of male advantage over female people.

ANOTHER STUDY ON THE IMPACT OF TESTOSTERONE ON SPORT

Hormonal Basis of Biological Sex Differences in Human Athletic Performance

Jonathon W Senefeld, Sandra K Hunter
2 April 2024

https://academic.oup.com/endo/article-abstract/165/5/bqae036/7639012

Abstract ( I have added paragraph breaks to highlight the pertinent points)

“Biological sex is a primary determinant of athletic human performance involving strength, power, speed, and aerobic endurance and is more predictive of athletic performance than gender."

"This perspective article highlights 3 key medical and physiological insights related to recent evolving research into the sex differences in human physical performance: (1) sex and gender are not the same; (2) males and females exhibit profound differences in physical performance with males outperforming females in events and sports involving strength, power, speed, and aerobic endurance; (3) endogenous testosterone underpins sex differences in human physical performance with questions remaining on the roles of minipuberty in the sex differences in performance in prepubescent youth and the presence of the Y chromosome (SRY gene expression) in males, on athletic performance across all ages."

"Last, females are underrepresented as participants in biomedical research, which has led to a historical dearth of information on the mechanisms for sex differences in human physical performance and the capabilities of the female body. Collectively, greater effort and resources are needed to address the hormonal mechanisms for biological sex differences in human athletic performance before and after puberty.”

The graphic that I have attached is interesting. I have not had access so this is a screen shot from the thumbnail. It covers male advantage from very young ages. And there is another testosterone chart showing massive gap between male and female.

SWYER SYNDROME - POST BY DR EMMA HILTON

https://x.com/FondOfBeetles/status/1819697582647484898

3rd August, 2024

Have had a couple of requests to run through another XY DSD called Swyer syndrome. I’m not clear why Swyer would be on the table here, but here goes.

The first step in reproductive system development is making either testes or ovaries. After they have been made, they coordinate (via hormones) a lot of what happens after (building all the internal plumbing, the external genitals etc).

Making either testes or ovaries is coded by genes. One on the Y chromosome is called SRY, and when it is present, the baby starts to make testes.

With Swyer Syndrome, baby is conceived with XY chromosomes. But sometimes the SRY gene is missing/broken, or sometimes other genes that SRY hooks up with are missing/broken.

This means that this XY baby cannot complete testes development. It doesn’t make ovaries instead, it effectively makes nothing, or maybe a weeny bit of residual, immature testes tissue.

Now, the rest of the baby’s body is waiting to get on with the job of internal plumbing and external genitals. “No testes” means there is no male hormone environment, and the rest-of-body reads this as “not male so must be female then”.

So baby’s body starts making female internal and external anatomy. At birth, baby is observed as female.

Crucially, with no testes making testosterone, Swyer syndrome doesn’t include the typical aspects of male development that are relevant for sport. Babies don’t masculinise in any hormone-driven way (although people with Swyer are a little taller than females).

So individuals with Swyer are included, without sanction or question (at least in current regulations), in female sport.

RE: WHY MIXED SEX CATEGORISATION/STRATIFICATION DOES NOT WORK USING WEIGHT LIFTING AS AN EXAMPLE

From Dr Emma Hilton on Twitter (FondOfBeetles)

"A few years ago, for USA Powerlifting, I mapped weightlifting/powerlifting strength between males and females. Using real world data from multiple competitive environments, I found that a 66 kg male can lift the same weight as a female who weighs around 91 kg. In powerlifting, when you disaggregate by type of lift, the majority of total male advantage is in the bench press (upper body). Just saying."

I have attached the chart that shows the advantage.

CAS FINDING (REDACTED) CASTER SEMENYA VS IAAF 2018

https://www.sportsintegrityinitiative.com/wp-content/uploads/2019/07/Award-5794-final-with-redactions-for-publication-compressed.pdf

ARBITRAL AWARD
Delivered by the
COURT OF ARBITRATION FOR SPORT
sitting in the following composition:

Has some interesting quotes (the brackets indicate redaction):

"Dr. Berman stated that individuals with 46 XY DSD are around 140 times more prevalent among elite international athletes than among the general female population. (He illustrated this by explaining that at the 2017 IAAF World Championships in London, at least[...] out of958 female athletes had a 46 XY DSD.) According to Dr. Berman, this statistical overrepresentation of 46 XY DSD individuals constitutes clear, albeit indirect, evidence of the performance enhancing effect of adult male levels of circulating testosterone".

and

"Some individuals with PCOS may have elevated endogenous testosterone. In those cases the level is normally under 5 nmol/L. There may, however, be rare cases in which the level is over 5 nmol/L. The published literature suggests that (a) there is approximately a 1 in 10,000 chance that a woman with PCOS will have testosterone over 4. 8 nmol!L; and (b) there is an approximately 1 in 20,000 to 1 in 30,000 chance that a woman with PCOS will have testosterone over 5 nmol/L."

"If a woman with PCOS has testosterone over 5 nmol/L there is a serious risk that she has an adrenal tumour, which needs to be investigated."

and

"46 XY individuals generally have greater lean body mass, larger hearts, higher cardiac output, larger haemoglobin mass and larger V02 max than 46 XX individuals. The single biggest reason for the sex differences in these physical attributes is exposure in 46 XY individuals with functional androgen receptors to much higher levels of testosterone during growth and development (puberty) and throughout the athletic career."

and

"According to the IAAF's expert evidence, a repotied 58-63% of 5-ARD persons who were assigned the female sex at birth change to the male sex when these secondary sex characteristics develop at puberty."

and

"An androgen-sensitive individual with circulating testosterone between 5 and 10 nmol/L will have an ergogenic advantage both in terms of muscle mass and strength and in terms of levels of circulating haemoglobin over an individual with circulating testosterone below 5 nmol/L."

CASE STUDY ON LIA THOMAS'S RETAINED MALE ADVANTAGE

https://journals.physiology.org/doi/full/10.1152/japplphysiol.00751.2022

Case Studies in Physiology: Male to female transgender swimmer in college athletics

11April 2023
Jonathon W. Senefeld, Sandra K. Hunter, Doriane Coleman, and Michael J. Joyner

RESULTS

Transgender Woman Swimmer Performance Changes

"After about 2 yr of both feminizing GAHT and elite-level swimming training, swimming performance times by a transgender woman were slower by ∼5% across all relevant swimming event distances (Table 1 and Fig. 1). Although the small sample size of four observations may interfere with accurate inference from a correlation (13), there appears to be a linear relationship between performance times in the men’s category and the women’s category (R2 = 1.0, P < 0.001). The relationship between the performance times in the men’s category (before GAHT) and women’s category (after GAHT) can be described using the following equation: women’s category time = (men’s category time) × 0.9281 + 4.2546. The difference in performance times between the male category and female category also appeared to be associated with performance distance, such that the smallest decrement in performance was observed in the shortest event distance (0.5%, 100 yard) and the largest decrement in performance was observed in the longest event distance (7.3%, 1,650 yards; Table 1). Despite slower performances, the transgender woman swimmer experienced improvements in performance for each freestyle event (100 to 1,650 yards) relative to sex-specific NCAA rankings, including producing the best swimming time in the NCAA for the 500 yard distance (Table 1)."

and

"First, the declines in freestyle swimming performance for the transgender woman swimmer after about 2 yr of feminizing GAHT (0.5% for the 100 to 7.3% for the 1,650 yard distance) were less than sex differences observed among the top world record performances (11.4% for the 100 to 9.3% for the 1,650 yard distance)"

A handy graphic is below.

WASHINGTON POST OPINION ARTICLE

By Doriane Lambelet Coleman
August 16, 202

https://www.washingtonpost.com/opinions/2024/08/16/womens-sports-transgender-dsd-olympics/

This is a good overall and updated discussion piece with some interesting links.

'Separating athletes in competition on the basis of sex is the only way to account for the female half of the population. No other sorting tool works to achieve this inclusion goal — not height, weight or any other physical characteristic.'

and

"The essential example is Katie Ledecky, who is said to be “better at swimming than anyone is at anything.” She just won an unprecedented fourth straight Olympic gold medal in her best event, the 800-meter freestyle. Her world record time in that event — 8:04.79 — shows up at No. 26 among the best American 15- to 16-year-old boys."

Ross Tucker shared this today on Twitter…

https://onlinelibrary.wiley.com/doi/epdf/10.1111/sms.14715

Twitter thread…

https://x.com/Scienceofsport/status/1826606800063393865

KATIE LEDECKY VS SCHOOLBOYS

CHART FOR THE ABOVE

This is a great reference to counter the 'but these male competitors in female sports are not mediocre male athletes'. Because, if those male competitors are swimming close to Katie's times.... yes they are mediocre!

CHELSEA WOMEN'S FOOTBALL AND MENSTRUAL CYCLE IMPACTS

https://www.chelseafc.com/en/news/article/chelsea-women-tailor-training-to-players-menstrual-cycles

14 February 2020

Chelsea Women tailor training to players' menstrual cycles

Chelsea FC Women manager Emma Hayes has this week revealed the club are using a specialist app to tailor their training programme around players’ menstrual cycles in an attempt to enhance performance and cut down on injuries.

Hayes and her staff have designed players’ individual plans around the phases of their menstrual cycle with the belief that factoring in the menstrual cycle to training and nutrition regimes could help control the weight fluctuations which often affect athletes during certain phases of their cycles.

This in turn can reduce a player's susceptibility to soft tissue injuries, such as anterior cruciate ligament damage, which has been linked to menstruation.
‘The starting point is that we are women and, ultimately, we go through something very different to men on a monthly basis,’ said Hayes.

‘We have to have a better understanding of that because our education failed us at school; we didn’t get taught about our reproduction systems. It comes from a place of wanting to know more about ourselves and understanding how we can improve our performance.

Last February, Hayes met physiologist and international cross-country runner Dr Georgie Bruinvels, who has developed the FitrWoman app for sports science company Orreco. The app allows women to input information about their menstrual health and related symptoms, which can then be logged and monitored.

Hayes, along with her backroom staff and other members of the management team, have encouraged players to download the app and, with the consent of the players, Chelsea’s coaches access this information and tailor their training programmes.

Dr Bruinvels visits Chelsea once a fortnight and instructs staff and players on the use of the app and how it can be applied to training to optimise performance. Players learn how to track their menstrual cycle across the four phases: menstruation, pre-ovulation, the time between ovulation and premenstrual symptoms and the premenstrual phase itself.

A player can be affected in different ways depending on the phase of their cycle. They can lose co-ordination during phases one and four and often crave junk food during phases three and four, which can lead to weight fluctuations.

Understanding more about the subject could also have a significant impact on preventing injuries, as there can be a higher injury risk during phases one and two. This ranges from serious injuries – research has suggested a link between anterior cruciate ligament injuries and hormonal fluctuations – to less severe soft tissue problems, which are more likely to occur during the first half of a cycle.

‘The menstrual cycle is an inflammatory process and excess inflammation can result in an injury,’ said Dr Bruinvels ‘It’s not solely down to high levels of oestrogen, but tracking the cycle is also very important in terms of bone-injury risk.’

Talking about how this could change the game for the better, Hayes added: ‘We view ourselves, in a lot of ways, as leaders of the game and it would be amazing if others started doing this.

‘These players are going to be the first generation of women who are well educated about their menstrual cycle and they will spread that knowledge as far as they possibly can and we hope that becomes a culture within every football club in the world, so everybody can cope better with their menstrual cycles.’

Hellofabore
Somehow I'd missed this thread until now - I have a lot of catching up to do.

Thank you for your hard work in compiling all this information.

In case you're dealing with someone who comes over with a fit of the vapours at the very mention of Mumsnet, I've archived the version of the magazine that has the English translation
web.archive.org/web/20240822211426/www.lepoint.fr/monde/2024-olympics-imane-khelif-was-devastated-to-discover-out-of-the-blue-that-she-might-not-be-a-girl-14-08-2024-2567924_24.php

RE: PREPUBERTAL ADVANTAGES MALE VS FEMALE & WHETHER SUPPRESSION OF TESTOSTERONE WORKS

Podcast by Paradox Institute with Greg Brown, Sports Scientist

Sports scientist and professor of Exercise Physiology Greg Brown joins us to discuss his research on the prepubertal advantages boys have over girls, along with the general sex differences that create male advantage.

Here is some of Brown’s research published February 2024.

Sex-based differences in track running distances of 100, 200, 400, 800, and 1500m in the 8 and under and 9–10-year-old age groups

Gregory A Brown, Brandon S Shaw, Ina Shaw

5th February 2024

^https://onlinelibrary.wiley.com/doi/10.1002/ejsc.12075^

"In conclusion, although some have stated that sex-based differences in athletic performance do not arise until puberty, the present data indicate that in the 8 and under and 9–10-year-old age groups males run faster than females in distances of 100, 200, 400, 800, and 1500m. While some females in these age groups are faster than some males, the average male finalists are faster than the average female finalists, and the fastest males are faster than the fastest females. As running is a key component of many sports, these sex-based differences between prepubertal males and females should be considered when sport governing bodies and policy makers consider the issue of sex-based sporting categories"

HECHEATED.ORG

A site that tracks male people, whether gender identified or a male with a DSD who has benefited from any degree of male puberty, who have won prizes and podium places in female sports.

https://www.hecheated.org

I do not at the moment know who has put this resource together (on Twitter they are hecheateddotorg ) but this is part of its About page. Only use the information it has published if you check it first would be my recommendation.

“HeCheated.org was largely inspired by SheWon.org. SheWon.org is an ever-evolving, ever-growing database of female athletes who have lost medals, podium spots, records, awards, and other athletic accomplishments and opportunities due to male participation in the female athletic division.”

”While SheWon.org seeks to give these women and girls the recognition they deserve,”

”HeCheated.org seeks to call out these male athletes and expose the damage that they have each caused to women and girls in sports.”

“On this site, you will find men and boys, males of all ages and competition levels, from high school to masters, amateur to professional.”

“At each level and in each age category, these male athletes are dominating female sports, setting records, stealing podium spots, medals, award money, positions on national teams, and causing women and girls to be excluded from our own sporting category whether through failure to qualify for limited spots in championship matches, being passed over in team selection for a male athlete, or self-exclusion due to the blatant unfairness and demoralization faced when required to face off against a male opponent.”