Full contact ‘collision’ sports are those where deliberate, forceful contact against an opponent are an integral part of gameplay.

The aim of contact play may be to defend or retrieve possession of, say, a ball (e.g. rugby) or to win by disabling your opponent (e.g. boxing).
Sports federations regulating full contact sports, where contact cannot be eliminated without changing the face of the sport, have a *special duty* to minimise the potential for injury during gameplay.

See Jon Pike @runthinkwrite on this.

This is evident in policies to, for example, limit contact to specific moves or regions of the body, to regulate how contact is enacted, and the wearing of protective gear to minimise injury potential during contact.
Boxing is perhaps the most mainstream of heavy collision sports, where one route to winning is to directly disable your opponent by maximum force punching to the head, to effect loss of consciousness.

i.e. spark your opponent out.
Males have extensive advantage over females in boxing. Upper body strength is far larger in males (larger than the difference in lower body strength). Males have wider shoulders and more force through upper body rotation. They have longer arms and bigger hands.
The differential force through a punch motion is 162% higher in males than females.

And females have thinner skulls and weaker neck muscles, providing far less resistance to vastly superior punch force.
Of all the mainstream sports where inclusion of transwomen in female categories is under the microscope, boxing is, quite simply, a sport that cannot afford to follow standard-issue IOC guidelines (T suppression for a year before competition).
The current trans policy from Boxing Canada @boxing_canada is flawed, and dangerous.

They do not outline safety assessments for transmen wishing to compete in the male category.

Many think consent to compete in the male cat is sufficient, and regulating inclusion of transmen on safety grounds is ‘paternalistic’.

This is boxing, not track running.
If a transman is assessed as sufficiently strong to fight with males without unique risk of serious injury, that’s one thing. To not bother with assessments is another.
The policy permits inclusion of transwomen in the female cat after 12 months of T suppression, despite this regime being wholly insufficient to reduce muscle mass and strength acquired during male puberty to any meaningful degree.
The policy does not permit case-by-case exclusion of transwomen, when there is overwhelmingly obvious retention of male advantage.

You think Anthony Joshua - 6’6’’ and 110kg - would be safe to fight females after 12 months of T suppression and 5% down on strength?
Proponents of inclusion have suggested just that.


Oh wait, only if Joshua were similar height/weight as her opponent...

OK, Golovkin (left) .v. Cederoos (right).
Male athletes can be 30% stronger than female athletes of the same height/weight.

From Hilton and Lundberg, 2021:

You think a male boxer suppressing T, who might lose around 5% of their strength (assuming they don’t train to maintain), can fairly - and more importantly *safely* - box against a height/weight matched female?
Federations that regulate boxing need to think about how they construct trans policies, because they simply cannot blindly adopt the same rules that regulate track running.
It’s perfectly OK to identify your sport as somewhat exceptional, thus requiring more stringent rules.

In fact, you have a special ethical duty to do so, for the sake of your female athletes.

@JaneCouchMBE @NicolaAdamsOBE

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More from @FondOfBeetles

6 Mar
There have been two academic reviews of musculoskeletal changes in transwomen suppressing testosterone.

Both conclude that loss of muscle mass and strength is small, and that strength advantage over females is retained.

Citations to follow.
The first review is Hilton and Lundberg, 2020, published in Sports Medicine.


The second review is Harper et al., 2021, published in the British Journal of Sports Medicine.

Read 8 tweets
3 Mar
Systematic review from Joanna Harper on muscular changes in transwomen.

‘These findings suggest that strength may be well preserved in transwomen during the first 3 years of hormone therapy.’

Her conclusions mirror those of a recent review by me and Tommy Lundberg @tlexercise

‘These longitudinal data comprise a clear pattern of very modest to negligible changes in muscle mass and strength in transgender women suppressing testosterone for at least 12 months.’
Link to our review here:

Read 6 tweets
27 Feb
Over the past month or so, I have been testing the hypothesis ‘Doing X causes Y to happen’.

So I have been ‘Doing X’ a repeated number of times and scoring how often it ‘causes Y to happen’.
If I don’t do X, Y rarely happens, but there is a background rate of Y happening in the absence of X.

If I do X, Y almost always happens, but there have been a few times where it didn’t happen.
Not doing X = Y happens in 4/60 tests.

Doing X = Y happens in 57/60 tests.

It’s clear to me (and statistically) that ‘Doing X’ does indeed correlate with ‘Y happening’, and I have a well-known mechanism to assert not just correlation but cause.
Read 8 tweets
23 Feb
Excellent piece here from Jon Pike @runthinkwrite

I’ve often struggled to articulate the fallacious ‘Range Argument’. Jon makes a good job of it.
‘According to the range argument, however, lots of male-born people, including transwomen, are in the range of females. This means they are not necessarily faster or stronger than the fastest or strongest female athletes just because they were born male.’
‘So, if transwomen are “in the range” of female athletes, then their inclusion in sport is still fair, right?
Read 4 tweets
21 Feb
The argument that sports categories be divided according to current testosterone completely misunderstands the biological function of testosterone.
It assumes symmetry - that is, if T causes X, removing T will remove X.

That is intuitive and sometimes true, but not necessarily so. Any developmental biologist will tell you that the effects of a molecule on a target system are not always reversible.
Target tissues can be induced to develop in ways that are irreversible or heavily resistant to change.

Once such a developmental change is set, removing the trigger makes no difference.
Read 15 tweets
19 Feb
@GaryLineker Hi Gary. People have tried to get me sacked/suspended for questioning the fairness of inclusion of transwomen in female sports (see pinned academic review for more info).
@GaryLineker Fortunately, my institute has been supportive of my voice.

The same institute whose students no platformed tireless feminist activist and advocate Julie Bindel @bindelj from a debate, ironically, about free speech.

I’ve been lucky. Many other women less so.
@GaryLineker @bindelj In the course of my research, I’ve met some fantastic national and international female athletes, current and retired, who are terrified of even raising questions about current sports policies.
Read 6 tweets

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