Transgender And Cisgender Women Have Similar Physical Fitness – Expert Reaction

Trans and cisgender women have comparable fitness despite
differences in muscle mass, finds a review of 52 previous
studies.

The systematic review and analysis by
overseas scientists in British Journal of Sports
Medicine looked at data on body composition – fat and
muscle mass – and physical fitness of trans and cisgender
people.

After 1-3 years of hormone therapy,
transgender women didn’t show observable differences to
cisgender women in upper and lower body strength, or in a
key measure of heart and lung fitness (VO max).

The
authors say there are many limitations to their review and
we need more long-term studies, but conclude that current
evidence doesn’t show “inherent athletic advantages”
for transgender women.

The Science Media Centre asked
local experts to comment.

Research Associate
Professor Kim Meredith-Jones, Director of the Bone and Body
Composition Research Unit, University of Otago,
comments:

“I am not a clinical expert in
gender-affirming hormone treatments. My perspective comes
from experience measuring body composition, and some very
cursory clinical experience working with adolescent
transgender populations. With that context in mind, these
findings are interesting, but they need to be interpreted
carefully.

“Although this review included a large
number of transgender participants overall, most were
adults. This means the results cannot tell us what happens
for young people who use puberty blockers or begin medical
transition during adolescence. That remains an important
evidence gap.

“The finding that transgender women
had higher lean mass than cisgender women, but did not
differ in strength or aerobic fitness, should also be
interpreted with caution. These outcomes were often measured
in different groups of participants, rather than in the same
individuals. In addition, only a small number of studies
included fitness data, and strength testing was carried out
in far fewer participants than body composition
measurements. This makes it difficult to draw firm
conclusions about how muscle mass relates to physical
performance.

“Finally, the studies included in the
review varied widely in methods, hormone treatment duration,
and measurement techniques. While the results add useful
information to an evolving area of research, they should not
be seen as definitive and highlight the need for
better-designed, long-term studies that measure both body
composition and physical performance in the same
participants.”

Conflict of interest statement:
“I do not have any financial, professional, or personal
relationships that could be perceived to influence the
content or interpretation of this commentary and no funding
was received to support this commentary.”

Our
colleagues at the AusSMC, SMC Spain, and UK SMC have also
gathered comments. A selection follows – full comments
available on their websites: SMC
Spain, UK
SMC, AusSMC.

Professor
Ada Cheung is a Professor of Endocrinology at The University
of Melbourne, Australia

“Blanket bans on
transgender women in sport are not supported by the best
available evidence. This large new review, combining data
from more than 6,000 people across 52 studies, shows that
after gender-affirming hormone therapy, transgender women
are no different from cisgender women in body fat
percentage, muscle percentage, strength, or
cardiorespiratory fitness. While trans women are, on
average, taller and may retain slightly more absolute
muscle, this does not translate into meaningful advantages
in performance, such as strength or aerobic
capacity.

“What we still do not know precisely is
how long these changes take to fully converge after starting
hormone therapy, which is why sport needs evidence-based,
sport-specific guidelines rather than one-size-fits-all
rules.

“The idea that male puberty creates permanent
athletic advantage is not supported by current data if
someone is using gender affirming hormone therapy.
Restrictive bans also harm cisgender girls and women by
policing bodies and reinforcing narrow ideas about how women
are supposed to look or perform. Fairness and inclusion can
coexist.

“Instead of blanket bans, we need
eligibility criteria for elite sport, and we should focus on
the real work of supporting women’s sport: improving
visibility and pay, reducing sexual harassment and assault,
expanding access to facilities and coaching, and ensuring
fair media coverage. These changes actually advance equity,
while building sporting systems that are safe, inclusive,
and grounded in evidence.”

Ada has declared the
following: Professor Ada Cheung is a clinician scientist and
member of the World Triathlon Transgender Athlete
Eligibility Expert Panel and Formula Fixed Sport Science and
Equity Panel. Ada Cheung has received research funding from
NHMRC, Heart Foundation, Suicide Prevention Australia, The
Paul G. Allen Frontiers Group, University of Melbourne,
Endocrine Society of Australia, Royal Australasian College
of Physicians Foundation, Austin Medical Research
Foundation, Sir Edward Dunlop Medical Research Foundation
and Viertel Charitable Foundation. She is currently a member
of the Endocrine Society (US), European Society of
Endocrinology, Australian Medical Association, Endocrine
Society of Australia, World Professional Association for
Transgender Health and Australian Professional Association
for Trans Health.

Associate Professor
Phoebe Toups Dugas is from the Department of Human-Centred
Computing & Exertion Games Lab at Monash University,
Australia. She is a transgender
woman.

“Physical characteristics impact
sports performance. This affects players’ chance at a fair
go and their ability to socially enjoy their bodies. It
affects how interesting a competition is. Many sports
segregate based on sex, assuming that women and men have
knowable inherent characteristics that impact performance
– it turns out they’re neither knowable nor predictably
affect performance. This paper points out
that:

• identifying the impacts of hormones and
  sexual development on athletic performance is complex and
  poorly understood – there’s not consistent data, nor do
  physical characteristics predict
  performance;
• transgender women on hormone therapy
  become similar to cisgender women in terms of performance,
  despite retaining lean mass; and
• athletic
  performance is multifaceted, and attention to gender is not
  very useful.

“Adding in my experience as a
transgender woman in dance who studies transgender play –
being active and athletic in a trans body is transcendent,
and taking such an opportunity away is not backed by
science.

“We should identify IF and what
characteristics matter for a sport, non-invasively test for
them, and segregate using them instead. For example, if long
arms make one better at a sport, then maybe divisions based
on arm length make more sense than
gender!”

Phoebe Toups Dugas has declared: My
positionality is that of a transgender woman who is
interested in justice and
equity.

Professor Vincent Harley is from
the Centre for Endocrinology and Reproductive Health (CERH)
at Hudson Institute of Medical Research,
Australia

“This study is interesting and
large and shows no difference in upper or lower body
strength or oxygen consumption amongst sedentary transgender
women after one to three years of sex hormone therapy, when
compared to cisgender women. On this basis, the study
suggests that trans women do not have an athletic advantage
at a baseline level. So, from a community sport perspective
there is no reason to think transgender women would have an
advantage.

“This study does not inform performance
at an elite level. That would require a study of the
performance of transgender athletes in a specific sport –
a difficult task given their rarity. Exclusion of
transgender athletes from sport would hinder data
collection. The International Olympic Committee has stated
inclusion of trans athletes should be the default. So many
factors weigh in to success at the elite level – physique,
genetics, sports infrastructure, socio-economic and
psychosocial – so I’m not sure if being trans is another
factor, especially considering the very small number of
individuals involved.”

Vincent declares that he
has no conflicts of interest.

Connor
Macdonald is a Researcher and Lecturer from the College of
Business and Law at Adelaide University,
Australia

“As the authors of this study
have stated, those who advocate for blanket bans of
transgender women from participation in sport hinge their
argument on transgender women having inherent physical
advantages over cisgender women. These bans are most
obviously seen in the US at the federal level, and in Canada
at the provincial level in Alberta. As has been recognised
for some time, the science around inherent sport advantage
is inconclusive, yet those who have pushed campaigns against
inclusion have often relied on ‘common-sense’ arguments
that essentialise transgender and cisgender women. This
study challenges not only the taken-for-granted views that
transgender women retain sport-specific physical advantages
over cisgender women, but also the social construction of
transgender women and men.

“While the authors
conclude with a call for further study and developing
nuanced and context-dependent inclusion policies, I think
there needs to be further conversation around the social
constructions of sport and gender. Sport’s history as a
domain exclusively for men has produced discrepancies in
all women’s equitable access and participation in
sport. And while these historical implications are
constantly contested, there are still further opportunities
to change how sport can be practiced, and that starts with
inclusion.”

Connor declares that he has no
conflicts of
interest.

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