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.

From Dr Hilton and T Lundberg. This contains great information and quantifies some of the differences. You will find this study is very well referenced by many who use the findings to explain male pubertal advantage.

https://link.springer.com/article/10.1007/s40279-020-01389-3

Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage

Abstract: Males enjoy physical performance advantages over females within competitive sport. The sex-based segregation into male and female sporting categories does not account for transgender persons who experience incongruence between their biological sex and their experienced gender identity. Accordingly, the International Olympic Committee (IOC) determined criteria by which a transgender woman may be eligible to compete in the female category, requiring total serum testosterone levels to be suppressed below 10 nmol/L for at least 12 months prior to and during competition. Whether this regulation removes the male performance advantage has not been scrutinized. Here, we review how differences in biological characteristics between biological males and females affect sporting performance and assess whether evidence exists to support the assumption that testosterone suppression in transgender women removes the male performance advantage and thus delivers fair and safe competition. We report that the performance gap between males and females becomes significant at puberty and often amounts to 10–50% depending on sport. The performance gap is more pronounced in sporting activities relying on muscle mass and explosive strength, particularly in the upper body. Longitudinal studies examining the effects of testosterone suppression on muscle mass and strength in transgender women consistently show very modest changes, where the loss of lean body mass, muscle area and strength typically amounts to approximately 5% after 12 months of treatment. Thus, the muscular advantage enjoyed by transgender women is only minimally reduced when testosterone is suppressed. Sports organizations should consider this evidence when reassessing current policies regarding participation of transgender women in the female category of sport.

This second study is from Harper et al.

bjsm.bmj.com/content/early/2021/02/28/bjsports-2020-103106

Conclusions are in line with Hilton & Lundberg.

For information (considering many people will seek to discredit based on alleged bias) Harper is the transwoman who has released some sports studies in the past that had some methodology issues.

The USAF study. Again, one that people will often find referred to.

bjsm.bmj.com/content/early/2020/11/06/bjsports-2020-102329

Timothy A Roberts, Joshua Smalley, Dale Ahrendt

Effect of gender affirming hormones on athletic performance in transwomen and transmen: implications for sporting organisations and legislators

Summary The 15–31% athletic advantage that transwomen displayed over their female counterparts prior to starting gender affirming hormones declined with feminising therapy. However, transwomen still had a 9% faster mean run speed after the 1 year period of testosterone suppression that is recommended by World Athletics for inclusion in women’s events.

It is interesting reading as it also leaves the suggestion that even after 3 years advantage still exists.

And Sean Ingle’s take on it.

www.theguardian.com/sport/2020/dec/07/study-suggests-ioc-adjustment-period-for-trans-women-may-be-too-short

Here is an interesting video led by Prof Jo Phoenix, with Dr Emma Hilton and Jon Pike.

OUGCRN Seminar : Sex, Gender, and Sport after Tokyo

As they point out the 69 kg male weightlifting champion at 164 cm can lift more weight and any female weightlifting champion. Even Tatiana Kashirina who is 108 kg an 177 cm tall. She goes through Hubbard's advantages.

An interesting seminar particularly for anyone who perhaps wants a summary of sex vs gender or a reminder.

Does anyone have the male v female testosterone chart?

TESTOSTERONE LEVEL CHART - NORMAL FEMALE RANGE / PCOS RANGE / NORMAL MALE RANGE

USING DAVID HANDELSMAN INFORMATION INCLUDING THE LEVELS IOC SPECIFIED FOR TESTOSTERONE SUPPRESSION

This is the chart was made using information from the Handelsman et al 2018 paper below.

The 'Caster Semenya' line refers to what the IOC had specified that Semenya and others needed to suppress their testosterone levels down to, resulting in Semenya trying to overturn this at CAS.

Semenya was noted in that CAS case to have the difference in sex development categorised as 5-ARD and had testosterone levels of around 21 nmol/L.

The Hubbard line was the testosterone level that males with transgender identities had to suppress to for the 2020 Tokyo Olympics.

This is tweet where you can find the chart.

https://x.com/rorybowman/status/1819232725175620084

This is the study

Circulating Testosterone as the Hormonal Basis of Sex Differences in Athletic Performance

David J Handelsman, Angelica L Hirschberg, Stephane Bermon

Published: 13 July 2018

https://academic.oup.com/edrv/article/39/5/803/5052770?login=false

A poster once tried to say that Handelsman obviously supports testosterone reduction, however, this is untrue.

What is important to note here is that David Handelsman has since said this in 2022 on the SBS Insight episode after seeing further research.

“Question: does testosterone suppression get rid of the natural advantage males have?”

“It is important to remember that what we are talking about here is the unfair advantage so the objective is to eliminate it not just reduce it. But complete testosterone suppression has now be shown in a number of studies to not to fully nullify the advantages in males, in physical advantages for up to three years.”

“Suppression of testosterone is partially effective. It won’t change bones. They remain longer and stronger. Haemoglobin will change, but the key things muscle, heart and lungs virtually don’t change. Or they change very little, maybe 10 - 20% reduction. But 80% of the male physical advantage remains . So it is virtually incomplete, and no where near completely reversing male unfair advantage.”

“More on testosterone suppression:”

“The key thing is whether the male physical advantage is removed over a certain time. And the answer is there is no duration which removes the unfair male physical advantage of male bodied athletes in female events. The data shows that you can get some reversal, but no where near complete and therefore there remains an unfair advantage.”

5ARD INFORMATION FROM CAROLE HOOVEN

This is from Carole Hooven (hoovlet on Twitter).

It touches on the hormone AMH which is the hormone that stops the production of the uterus and fallopian tubes. It is produced in the testes of male people. And as such there are no ovaries, because the body developed testes instead.

There is are male conditions where this hormone is not produced. In Persistent Müllerian Duct Syndrome, male people with this still develop as ‘typical male’ developmentally.

https://x.com/hoovlet/status/1819449064590582073?s=46&t=HTxp6zCd4GZ2FFv4a-YeQ

The relevant parts of the tweet is below:

Males with 5-ARD do not have a uterus or other female internal structures, but they do have what looks like a vagina, so are often sexed as females. However they are males with normal testes, which produce typical male hormones. Those hormones, among other things, prevent the development of female internal reproductive structures (like the uterus and cervix).

In embryonic development, we all start out with two sets of primordial duct systems, one set that will develop into the male internal reproductive stuff (the Wolffian ducts, which become the epididymis, vas deferens and seminal vesicles), and another that develops into the female internal stuff (the Müllerian ducts, which become the upper part of the vagina, cervix, uterus and fallopian tubes, pic at the end).

In males, fetal testes don't only produce testosterone! They also make Anti-Mullerian Hormone (AMH), which is crucial for getting rid of the Mullerian ducts, and thus, ensuring that the eventual uterus, etc. don't develop. If there's no testes and no AMH, that female internal stuff will develop.

Males need high levels of T for male-typical development of all the male reproductive structures. Without T production and action, the external (penis and scrotum) and internal (described above) genitalia won't develop. But as I wrote in my monster tweet yesterday, T alone isn't enough for development of the penis and scrotum (and prostate): for that, T must be converted into DHT (a more potent androgen, production pathway below), and people with 5-ARD don't make the necessary enzyme to carry out that conversion. So they end up with what appears to be a vagina.

FYI, some males inherit a genetic mutation that means they can't produce AMH. They are typical males, but have a nonfunctional uterus and fallopian tubes inside their abdomen. The condition often not discovered until adulthood (it's called Persistent Müllerian Duct Syndrome). AMH is an important hormone for males, but hardly anyone even knows it exists.

Also, the testes generally don't descend into the scrotum before birth (as usual) without DHT, but they often do at puberty when testosterone levels reach high concentrations. So males with 5-ARD may be "sexed" as female, due to the female-appearing external genitalia.

But brain and the rest of the body are typically male. Most people with the condition will "transition" to living as a male once they realize they are male, and this often happens at puberty, when the testes descend and the body develops in a typically masculine way.

XY ATHLETES WITH TESTES: INFORMATION FROM CAROLE HOOVEN

Thread starts here there are charts linked in one of the tweets below:

First: People living with DSDs should be treated with compassion and understanding, and receive any heath care they need. These can be challenging conditions for individuals and their families. But when male athletes have DSDs that give them an advantage over females, and they compete in the female category, this raises concerns about safety and fairness, and forces discussion of the relevant physical traits.

Athletes with XY DSDs who have testes (usually internal), XY sex chromosomes, male-typical levels of testosterone, and functional androgen receptors are often described as females with "hyperandrogenism," i.e., abnormally high levels of testosterone. They experience physical benefits of this high testosterone during puberty, which translate into athletic advantages over females. The issue for sports is that athletes with the XY DSD 5-alpha reductase deficiency (5-ARD), may be socialized as female, may be legally female, and may live and identify as female; but they are male.

These individuals are usually born with female-appearing genitalia, which can lead to being sexed as female. Here's why. 5-ARD is caused by a mutation in the gene that codes for the enzyme 5-alpha reductase, which converts testosterone into a more potent androgen, DHT. This androgen interacts with the androgen receptor, like testosterone, and is necessary for the typical development of male external genitalia (penis and scrotum) and the prostate. Without DHT, female-typical external genitalia develop. At the end of this monster post is a graphic of the relevant steroid production pathway, from my book T: The story of Testosterone.

DHT is also responsible for male-pattern baldness and dark, coarse facial hair, which is why people with the condition have smooth skin that can give a feminine appearance.

The “decision makers” are aware that athletes with 5-ARD are male, and that they experience the benefits of male puberty. The requirement to reduce their testosterone to typical female levels isn’t discriminatory, since these are males who are asking to compete in the female category. But more significantly, all the relevant scientific evidence shows that reducing male T in adulthood does not undo the physical benefits of male puberty.

Here's more detail about T, DHT, and male advantage in strength and speed.

I've been asked if men with the DSD 5-ARD (in which ppl cannot convert testosterone into the more potent androgen DHT) experience the typical benefits of male puberty, that would give them an advantage in strength and speed relative to women. This is relevant to questions about whether male athletes with 5-ARD should be allowed to compete in the female category. This is an excellent question, because it could be the case that DHT is necessary for the development and maintenance of male-typical muscle, lean body mass and strength. If that were the case, then people with 5-ARD might not have a typical male advantage, because the lack of DHT would perhaps lead to a more feminine pattern of fat, lean body mass and strength. I've wondered about this myself and have looked into the evidence.

Perhaps the top researcher in this area, Shalendar Bhasin, who is scrupulous in his methods, has examined this very question. The answer appears to be: no, testosterone does not need to be converted to DHT to exert its typical anabolic effects. These findings are reported in his 2012 study, "Effect of Testosterone Supplementation With and Without a Dual 5α-Reductase Inhibitor on Fat-Free Mass in Men With Suppressed Testosterone Production, A Randomized Controlled Trial." (It is linked to below—and since it's paywalled, I've included the graphs that show comparisons between the placebo and DHT— inhibited conditions, with no difference on the various outcomes.)

For more detail, the investigators wanted to examine the effects of suppressing DHT on muscle mass, strength, and sexual function. This important because one of the treatments for benign prostatic hyperplasia and male-pattern baldness is to suppress DHT, but clinicians have been concerned about effects on other outcomes that affect health and quality of life. Participants (healthy men, 18 to 50, with normal T levels) had their T blocked, and were given graded doses of T, along with either placebo or a drug that blocked the conversion of T to DHT. So both groups had T, but only one, the placebo group, also had DHT. After 20 weeks of treatment, changes in lean body mass, muscle, and strength were assessed. There were no significant difference between the placebo and DHT-blocked groups in these outcomes.

For LOTS more detail, here's the relevant text from the results. Please don't ask me questions about the study. Just look at the abstract and results which you can find by Googling. The main point is that while there are predicted effects of the different doses of T received, there were no differences in the outcomes according to whether they had DHT blocked (with dutasteride) or not (placebo). "Fat-Free Mass Fat-free mass and lean body mass increased in a dose-dependent manner in the placebo and dutasteride [THIS IS THE DRUG THAT BLOCKS CONVERSION OF T TO DHT] groups (Figure 2).

The changes in fat-free mass were related to testosterone dose and changes in testosterone concentrations in the placebo and dutasteride groups but did not differ between groups; the dose-adjusted mean difference (placebo minus dutasteride) in fat-free mass was 0.50 kg (95% CI, −0.22 to 1.22 kg; P = .18). There was no significant interaction between testosterone dose and randomization to dutasteride or placebo, indicating a lack of evidence that the relationship of testosterone dose to change in fat-free mass differed between the dutasteride and placebo groups.

The model-based smoothed regression lines, obtained by generalized additive models, describing the relationship between changes in testosterone concentrations and changes in fat-free mass and lean body mass were similar in the placebo and dutasteride groups. Changes in fat mass were negatively related to testosterone dose and concentrations, but the relationship between change in fat mass and dose did not differ significantly between the placebo and dutasteride groups (P = .41; Figure 2)."

"Muscle strength Leg-press and chest-press strength increased dependently by dose in the placebo and dutasteride groups. Increases in leg-press and chest-press strength were greater with larger doses and higher concentrations of testosterone. These relationships did not differ between the placebo and dutasteride groups (Figure 2)."

Really interesting commentary from the authors on the role of DHT in adult men: "Why then did the steroid 5α-reductase system evolve for androgens? Forty-six XY males with steroid 5α-reductase deficiency exhibited ambiguous or female external genitalia at birth and poor prostate development, but underwent normal muscle and bone development during pubertal transition. The phenotype of these patients suggests that steroid 5α-reductase plays an essential role in the development of prostate and phallus by providing local amplification of an androgenic signal without systemic hyperandrogenemia during critical periods of sexual differentiation, illustrating nature's extraordinary ingenuity in creating mechanisms for tissue-selective amplification during development.

We speculate that in adult men, in whom this tissue-specific amplification is not essential because the circulating testosterone concentrations are substantially higher than those in the fetus, testosterone and DHT can interchangeably subserve many androgenic functions. When circulating testosterone concentrations are low, intraprostatic DHT formation may become important in maintaining prostate growth, thus buffering the effects of decreasing testosterone levels, which has been suggested by Marks et al.

Our data are consistent with studies that have reported no effects of 5α-reductase inhibitors on muscle or bone mass. Inferences from these trials are limited by the fact that administration of 5α-reductase inhibitors increases testosterone levels, rendering it difficult to ascribe the outcomes to differences in DHT levels alone. In our trial, inhibition of endogenous testosterone by administration of a gonadotropin-releasing hormone agonist eliminated this problem. Additionally, the high-dose dutasteride regimen effectively inhibited both steroid 5α-reductase isoenzymes."

https://x.com/hoovlet/status/1819041282594873759

and the charts are posted incase they are lost in the future but are in this tweet.

https://x.com/hoovlet/status/1819046454922518835

SEX MATTERS MEDIA BRIEFING PARIS OLYMPIC 2024 ABOUT MALE ATHLETES WITH TESTOSTERONE ADVANTAGE

Here is an informative Media briefing from Sex Matters including Developmental Biologist Professor/Dr Emma Hilton, plus the real life experience of competing with people with testosterone derived advantages, Olympians Mara Yamauchi and Sharron Davies.

DR EMMA HILTON ON THE GOLD REPORT

Dr Hilton is speaking about DSDs and sports in general. This is another excellent general information video and well worth watching the whole hour.

The Gold Report on YouTube ‘The BBC is lying'.

The BBC is Lying: Olympic Boxer Is NOT A Woman - Dr. Emma Hilton (4K) | heretics. 80

Excellent idea for a thread and thank you for all the resources you posted to seed it with!

Some websites that help illustrate the extent of males competing in women's sport:

www.shewon.org

www.hecheated.org

A visual depiction of male physical advantage in sports, comparing teenage boys to elite female athletes:

www.boysvswomen.com

ACADEMIC PAPER IN RESPONSE TO THE IOC FRAMEWORK

This a good paper for pulling a lot of the information available up until the end of 2023 together.

The IOC framework was released in November 2021, after there was so much pushback about male athletes such as Hubbard (and historically Semenya).

https://onlinelibrary.wiley.com/doi/epdf/10.1111/sms.14581

The International Olympic Committee framework on fairness, inclusion and nondiscrimination on the basis of gender identity and sex variations does not protect fairness for female athletes

February 1, 2024

Tommy R. Lundberg, Ross Tucker, Kerry McGawley, Alun G. Williams, Grégoire P. Millet, Øyvind Sandbakk, Glyn Howatson, Gregory A. Brown, Lara A. Carlson, Sarah Chantler, Mark A. Chen, Shane M. Heffernan, Neil Heron, Christopher Kirk, Marie H. Murphy, Noel Pollock, Jamie Pringle, Andrew Richardson, Jordan Santos-Concejero, Georgina K. Stebbings, Ask Vest Christiansen, Stuart M. Phillips, Cathy Devine, Carwyn Jones, Jon Pike, Emma N. Hilton

Perspectives:

The IOC framework on fairness, inclusion and nondiscrimination on the basis of gender identity and sex variations is misaligned with current scientific and medical evidence and offers insufficient protection of fair competition for female athletes within a female category. Also, it does not adequately engage female athletes, who are primary stakeholders in their sport. Male pubertal development results in large performance advantages in athletic sports, which necessitates a female category that excludes male advantages, to ensure equal opportunity through fair competition for female athletes at all levels of sport. There is currently no evidence that testosterone suppression in transgender women can reverse male development and negate male advantages. In contrast, there is convincing evidence that the male advantage persists even when testosterone is suppressed. As a result, sports face the uncomfortable reality that the inclusion of transgender women in female sports categories cannot be reconciled with fairness, and in some instances safety, for females in athletic sports. The IOC must reconsider its framework and revise the 10 principles to reflect scientific evidence and fundamental principles of fair competition. We also recommend implementing a system to enable female stakeholders to be consulted in this matter and to have their voices heard, recognized, and valued.

More from David J Handelsman:
Toward a Robust Definition of Sport Sex
Pub 05 April 2024

Proposes that "sports sex is primarily defined by an individual's experience of male puberty"
Sport Sex Classification table:

THE IOC 2021 FRAMEWORK

IOC FRAMEWORK ON FAIRNESS, INCLUSION AND NON-DISCRIMINATION ON THE BASIS OF GENDER IDENTITY AND SEX VARIATIONS

https://stillmed.olympics.com/media/Documents/Beyond-the-Games/Human-Rights/IOC-Framework-Fairness-Inclusion-Non-discrimination-2021.pdf#_ga=2.219716894.621299853.1686571450-594927581.1678187184

Could someone link the translation from French to English of the tércieme of Imane’s trainer please?

RE: PCOS & FEMALE PEOPLE WITH HIGHER TESTOSTERONE

This is from a PCOS advocate on twitter.

PCOS raises female testosterone to up to 5.5 nmol/L (and above 4 can cause serious issues).
5-ARD raised Caster's testosterone to 21 nmol/L.

twitter.com/NathanielHart72/status/1550916276490477568?s=20&t=E8muLvV5kUEpbPeemz8zwQ

Plus there is this:

twitter.com/seaningle/status/1537480540068225031?s=20&t=E8muLvV5kUEpbPeemz8zwQ

Sean Ingle (Guardian sports journalist) mentioned this

The latest scientific publications clearly demonstrate that the return of markers of endurance capacity to "female level" occurs within six to eight months under low blood testosterone, while the awaited adaptations in muscle mass and muscle strength/power take much longer (two years minimum according to a recent study). Given the important role played by muscle strength and power in cycling performance, the UCI has decided to increase the transition period on low testosterone from 12 to 24 months. In addition, the UCI has decided to lower the maximum permitted plasma testosterone level (currently 5 mol/L) to 2.5 mol/L. This value corresponds to the maximum testosterone level found in 99.99% of the female population.

Plus this discusses the ranges

^https://onlinelibrary.wiley.com/doi/epdf/10.1111/sms.14581^

The International Olympic Committee framework on fairness, inclusion and nondiscrimination on the basis of gender identity and sex variations does not protect fairness for female athletes

“In adulthood, circulating testosterone concentrations do not come close to overlapping between females (0.1–1.7 nmol/L) and males (7.7–29.4 nmol/L).”

plus that Hoovlet post with handy charts in the tweet

https://x.com/hoovlet/status/1819017510005407984

“Confirmed. No overlap in T levels between healthy men and women, and rarely in people with atypical levels”.

“Below I'll include some info from my book on T and sex diffs. First is an illustration of the combined data from a meta-analysis of studies on a healthy population (by David Handelsman), and another on T levels in ppl with medical conditions/DSDs (by Richard Clark). I've also included my text description of the data. The original illustration is from Doriane Coleman's excellent Sex in Sport article (link is in the graphic). She let me adapt it for my book but hers is clearer!”

If you are using the term 'woman with high testosterone', plus check your sources and don't spread misinformation. Female people with PCOS, women, DO NOT HAVE male levels of testosterone!

https://www.mumsnet.com/talk/womens_rights/5138713-thread-4-two-female-boxers-set-to-compete-at-paris-2024-were-previously-disqualified-from-womens-world-championship-for-having-xy-chromosomes?reply=137453779

PAPER ON MEANINGFUL COMPETITION BY JON PIKE

This paper goes through what competitive advantage means. Jon Pike is a Philosophy lecturer for the Open University and so this is a counter to the philosophical discussion around 'inclusion'. An argument successfully used by Harper (2015?) and McKinnon (2019) in discussions with the IOC, or so I believe.

The PHELPS argument for competitive advantage is referred to in this tweet which refers to the page numbers in the paper:

”The argument that Khelif's advantage does not matter because it is 'small' and 'like Michael Phelps's advantages' is false.”

“I mean, 'false' as in 'refuted', 'demonstrated to be wrong’.”

”Here you go - see particularly pp. 8-15:”

https://x.com/runthinkwrite/status/1819323178973331569

Why ‘Meaningful Competition’ is not fair competition

6th Feb 2023

www.tandfonline.com/doi/full/10.1080/00948705.2023.2167720

ABSTRACT

In this paper I discuss a new conception that has arrived relatively recently on the scene, in the context of the debate over the inclusion of transwomen (hereafter TW) in female sport. That conception is ‘Meaningful Competition’ (hereafter MC) – a term used by some of those who advocate for the inclusion of TW in female sport if and only if they reduce their testosterone levels. I will argue that MC is not fair.

I understand MC as a substitute concept, as an attempt to substitute for the perfectly serviceable concept of fair competition. It is an attempt at conceptual engineering that should be resisted. This is important because some International Federations have accepted MC as good coin, and the underlying theory of MC, which I explicate for the first time, underpins the stance taken by the IOC (International Olympic Committee) in its Framework Document.

To establish that the inclusion of TW in female sport meets the criteria of MC in the sense I explicate here, does not show that the inclusion of TW in female sport is fair. Such inclusion is not fair, and the proper currency of sport is fair competition. ‘Meaningful Competition’, on the other hand, is a snare and a delusion.

(note: my paragraph breaks to make it easier to read quickly, sorry Jon)

MENSTRUAL CYCLE IMPACTS ON FEMALE SPORTS

An article about the connection of injury with menstrual cycle.

https://www.economist.com/science-and-technology/2021/06/24/acl-injuries-are-a-growing-problem

Plug this into archive dot is for the full version if the link below does not work.

https://archive.is/cH8ax

June 18th 2021

One of the most curious features of ACL injuries, though, is that they afflict women far more often than men—as much as eight times more, some investigations suggest. Why this might be is the subject of intensive research. But a clue lies in an apparent connection with the menstrual cycle.

A study published in 2013, of a group of women skiers in the Alps, for example, found that those in the pre-ovulatory stage of the cycle were more than twice as likely to suffer an ACL tear than were those in the post-ovulatory stage. A four-year survey of 113 female England footballers, published in March, also found a clear correlation. Muscle and tendon injuries were far more common in the late follicular phase of the cycle, just prior to ovulation, than in the other phases.

The reason for this menstrual-cycle link is unclear. The ACL has oestrogen receptors, which might help to explain what is happening. But it is not unique among ligaments in this, and the receptors’ job is, in any case, obscure. Levels of oestrogen in the body do spike just before ovulation—the point when tear-frequency rises—but uncertainty remains about the exact link.

Other contributory factors to women’s higher ACL tear rate may be female body shapes and movement patterns. Compared with men, women have wider hips, more inverted knees and “over-dominant“ quad muscles (meaning that the quadriceps femoris muscle group in front of the thigh bone is relatively stronger than the hamstring group behind it). All these factors put pressure on the elaborate workings of the knee joint. Women also tend to land in a more flat-footed manner than men do, and to pivot more awkwardly.

PAPER FROM ENDOCRINE SOCIETY REGARDING IMPORTANCE OF CONSIDERING SEX AS A UNIQUE VARIABLE

Just for those who need to know the difference

A link to a recent paper from the Endrocrine Society.

Considering Sex as a Biological Variable in Basic and Clinical Studies: An Endocrine Society Scientific Statement

Aditi Bhargava, Arthur P Arnold, Debra A Bangasser, Kate M Denton, Arpana Gupta, Lucinda M Hilliard Krause, Emeran A Mayer, Margaret McCarthy, Walter L Miller, Armin Raznahan, Ragini Verma

Published: 11 March 2021

academic.oup.com/edrv/advance-article/doi/10.1210/endrev/bnaa034/6159361#.YG386Eqj1v4.twitter

Some key points:

-Sex is an important biological variable that must be considered in the design and analysis of human and animal research. The terms sex and gender should not be used interchangeably. Sex is dichotomous, with sex determination in the fertilized zygote stemming from unequal expression of sex chromosomal genes. By contrast, gender includes perception of the individual as male, female, or other, both by the individual and by society; both humans and animals have sex, but only humans have gender.

-The classical biological definition of the 2 sexes is that females have ovaries and make larger female gametes (eggs), whereas males have testes and make smaller male gametes (sperm); the 2 gametes fertilize to form the zygote, which has the potential to become a new individual. The advantage of this simple definition is first that it can be applied universally to any species of sexually reproducing organism. Second, it is a bedrock concept of evolution, because selection of traits may differ in the 2 sexes. Thirdly, the definition can be extended to the ovaries and testes, and in this way the categories—female and male—can be applied also to individuals who have gonads but do not make gametes.

-many people cannot make either eggs or sperm, yet are recognized as female or male based on other physical characteristics; people who do not have either ovaries or testes are rare. For individuals that possess a combination of male- and female-typical characteristics, these clusters of traits are sufficient to classify most individuals as either biologically male or female.

-Biological sex is dichotomous because of the different roles of each sex in reproduction. For scientific research, it is important to define biological sex and distinguish it from other meanings.

There are plenty of interesting points in this paper.

However, it does focus too on the importance of clarity around male and female for medical purposes and treatment outcomes.

NZ REVIEW ON WHY TESTOSTERONE SUPPRESSION IS NOT A FIX FOR MALE PUBERTAL ADVANTAGES

The New Zealand review of whether IOC 10nm/l would work to reduce advantage. It is actually rather a good explainer.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9331831/#B44-ijerph-19-09103

Transwoman Elite Athletes: Their Extra Percentage Relative to Female Physiology

Alison K Heather, Stacy T. Sims, Academic Editor and Christopher T. Minson, Academic Editor

August 2022

Abstract:

There is increasing debate as to whether transwoman athletes should be included in the elite female competition. Most elite sports are divided into male and female divisions because of the greater athletic performance displayed by males. Without the sex division, females would have little chance of winning because males are faster, stronger, and have greater endurance capacity. Male physiology underpins their better athletic performance including increased muscle mass and strength, stronger bones, different skeletal structure, better adapted cardiorespiratory systems, and early developmental effects on brain networks that wires males to be inherently more competitive and aggressive. Testosterone secreted before birth, postnatally, and then after puberty is the major factor that drives these physiological sex differences, and as adults, testosterone levels are ten to fifteen times higher in males than females. The non-overlapping ranges of testosterone between the sexes has led sports regulators, such as the International Olympic Committee, to use 10 nmol/L testosterone as a sole physiological parameter to divide the male and female sporting divisions. Using testosterone levels as a basis for separating female and male elite athletes is arguably flawed. Male physiology cannot be reformatted by estrogen therapy in transwoman athletes because testosterone has driven permanent effects through early life exposure. This descriptive critical review discusses the inherent male physiological advantages that lead to superior athletic performance and then addresses how estrogen therapy fails to create a female-like physiology in the male. Ultimately, the former male physiology of transwoman athletes provides them with a physiological advantage over the cis-female athlete.

Conclusion:

Testosterone drives much of the enhanced athletic performance of males through in utero, early life, and adult exposure. Many anatomical sex differences driven by testosterone are not reversible. Hemoglobin levels and muscle mass are sensitive to adult life testosterone levels, with hemoglobin being the most responsive. Studies in transgender women, and androgen-deprivation treated cancer patients, show muscle mass is retained for many months, even years, and that co-comittant exercise mitigates muscle loss. Given that sports are currently segregated into male and female divisions because of superior male athletic performance, and that estrogen therapy will not reverse most athletic performance parameters, it follows that transgender women will enter the female division with an inherent advantage because of their prior male physiology.

The current IOC regulations allow transwomen athletes to compete if testosterone levels have been lowered to <10 nmol/L for 12 months prior to competition. While this begins to address the advantageous effects of circulating testosterone on athletic performance, it does not take into account the advantage afforded by testosterone exposure prior to transitioning. The existing data suggests that lowering testosterone to less than 10 nmol/L for 12 months decreases muscle mass but not to biological female levels and despite the decrease in mass, muscle strength can be maintained, especially if concurrently exercising. Estrogen therapy does not affect most of the anatomical structures in the biological male that provide a physiological benefit. Hemoglobin levels are lowered by estrogen therapy, and consequently, maximum aerobic effort may be lower, but this parameter will only be manifested if testosterone levels are suppressed to levels within the biological female range and maintained for extended periods of time. Reported studies show it is difficult to continuously suppress testosterone in transgender women. Given that the percentage difference between medal placings at the elite level is normally less than 1%, there must be confidence that an elite transwoman athlete retains no residual advantage from former testosterone exposure, where the inherent advantage depending on sport could be 10–30%. Current scientific evidence can not provide such assurances and thus, under abiding rulings, the inclusion of transwomen in the elite female division needs to be reconsidered for fairness to female-born athletes.

This dailymail link discusses it.

https://www.dailymail.co.uk/health/article-12111455/The-trans-advantage-womens-sports-explained.html

VIDEO ON INCLUSION IN SPORTS BY FAIRPLAY FOR WOMEN

The Inclusion Delusion
with Sharron Davies, Mara Yamauchi, Daley Thompson & Dr Emma Hilton

It is only 6 minutes.

NON-BINARY INCLUSION

Performance of non-binary athletes in mass-participation running events

bmjopensem.bmj.com/content/bmjosem/9/4/e001662.full.pdf

John Armstron, Alice Sullivan, George M Perry

December 21, 2023

“Our results illustrate the value of data on sex and gender identity.”

“The differential between natal male and natal female performances is better explained by differences in sex than differences in gender identity, as this differential persists for our non-binary cohort. This provides evidence against the theory that an individual’s gender-identity plays a significant role in these disparities in addition to their sex.”

“Our exploratory analysis indicates that non-binary athletes may have slower race times than other athletes once one controls for sex and age, but one would wish to confirm this with a larger data set as this is on the boundary of statistical significance. Data gathered on gender non-conforming college students by the American College Health Association suggest that gender non-conforming students are less likely to meet exercise recommendations, have increased rates of obesity and have higher rates of physical and mental health issues; these factors affect levels of fitness and training status. A complex range of factors associated with non-binary status could account for any association with slower race times. We do not wish to suggest causality in either direction.”

ARTICLE ABOUT TESTOSTERONE AND FAIRNESS HILTON HANDELSMAN

https://archive.ph/C84Be

What science tells us about transgender women athletes

Hilton and Handelsman 9 May 2022, The Australian

“Men are, on average, bigger, faster, stronger and have greater endurance than women,” Hilton and Handelsman wrote. “While there is overlap between men and women, at the elite sporting levels the differences are stark. These physical advantages are caused by the dramatic surge in testosterone — a rapid 20-30-fold rise over unchanged female levels — during male puberty. Cumulative effects of male testosterone exposure over years produce a lasting uplift of larger and stronger muscles and bones, higher capacity cardiovascular systems and a higher hemoglobin level.”

“In individual sports such as athletics and swimming, world records and winning Olympic performances show men have a 10-20 percent advantage over women, with even higher advantages in certain sporting skills (pitching, fast bowling, punching, yanking, pulling) of 50 percent to over 100 percent,”

“This explains why female world records are surpassed by thousands of males, including by boys aged 14-15 years old in early to mid-puberty”.

“Importantly, female athletes should not be forced to assume the burden of competing against unfair male physical advantages in the name of inclusion. This would risk creating another generation of female athletes with lifelong career loss and personal grievances resembling a very different form of unfair disadvantage such as when Australian and other sportswomen faced doped East German athletes in the 1980s.”

This is the coach who has been said to have scouted for athletes in South Africa, including Caster Semenya.

Ekkart Arbeit is the sports coach who was coaching the East German women, then came to Athletics Australia in the late 90s ( 1997?) in lead up to Sydney 2000 Olympics to coach the women but they rescinded his contract in 1998. Arbeit eventually ended up as the coach for South Africa in the mid 2000s.

He is a testosterone expert.

https://www.abc.net.au/news/2003-04-22/olympic-champion-hires-former-east-german-drug/1841668

https://www.irishtimes.com/sport/further-checks-on-coach-ordered-1.114105

MALE CHILDREN ADVANTAGES IN SPORT

Danish study on VO2 max and LBM in children from age 6

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1725036/pdf/v039p00725.pdf

Maximum oxygen uptake and objectively measured physical activity in Danish children 6-7 years of age: the Copenhagen school child intervention study

Eigberg, Hasselstrom, Gronfeldt, Friberg, Svensson, Anderson
October 2005

Objectives: To provide normative data on maximum oxygen uptake (Vo(2)max) and physical activity in children 6-7 years of age and analyse the association between these variables.

Methods: Vo(2)max was measured in 366 boys (mean (SD) 6.8 (0.4) years of age) and 332 girls (6.7 (0.4) years of age) from preschool classes in two suburban communities in Copenhagen, during a progressive treadmill exercise. Habitual physical activity was measured with accelerometers.

Results: Boys had higher Vo(2)max both in absolute values (1.19 (0.18) v 1.06 (0.16) litres/min (+11%), p<0.001) and relative to body weight (48.5 (6.0) v 44.8 (5.6) ml/kg/min (+8%); p<0.001) than girls. The difference in Vo(2)max between boys and girls decreased to +2% when expressed relative to lean body mass (LBM). Absolute Vo(2)max was related to LBM, body mass, and stature (all p<0.001). Boys were more physically active than girls (mean counts +9.4%, p<0.001), and even when boys and girls with the same Vo(2)max were compared, boys were more active. The difference in physical activity between the sexes was higher when sustained activity of higher intensity was compared.

Conclusions: Vo(2)max is higher in boys than girls (+11%), even when related to body mass (+8%) and LBM (+2%). Most of the difference in Vo(2)max relative to body mass was explained by the larger percentage body fat in girls. When boys and girls with the same Vo(2)max were compared, boys engaged in more minutes of exercise of at least moderate intensity.

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Australian children

https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=021cccdaed57d120bb05bac71c05ee82b0c5b315

Greek ( for those who have access)

https://www.tandfonline.com/doi/full/10.1080/17461391.2015.1088577?needAccess=true

This link has many links and is particularly good for children’s advantages.

https://www.ultraphysical.us/p/beyond-t-sex-based-differences-in

Gregory Brown, Professor Exercise Science (primarily Exercise Physiology) at the University of Nebraska at Kearney.