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Trans Women in Sport: What Does the Science Say?

Authors: Dr Sav Zwickl, Eli Ward-Smith, and A/Prof Ada Cheung


Content warning: This blog contains reference to exclusion of, and discrimination against, trans people in sport.


 

 

A trans woman jogging outdoors, wearing headphones

A trans woman jogging. Credit: FG Trade via iStock.


In recent years, significant attention has been directed at trans women in sport. This has included the spread of misinformation and disinformation including inaccurate depictions of trans athletes in the media. In turn, some international, national, and local sporting bodies have developed policies regarding trans women that are based on opinion rather than scientific evidence.


Much of these ‘debates’ and trans-exclusionary policies are based in the presumption that trans women have a performance advantage over cisgender women. This presumption is based on the fact that generally speaking, cisgender men have an advantage over cisgender women when it comes to strength, speed, and endurance. However, even though trans women may have gone through a testosterone-dominant puberty, this does not automatically mean they will have the same advantage over cisgender women in sport.


Trans women are different to cisgender men and feminising gender-affirming hormone therapy (GAHT) results in rapid and dramatic changes in the body. Some of these changes factor into physical performance. 


 

Empty Estradot estrogen packets sitting on a table

Estradot, which is used by some trans women. Credit: Nicola K via Shutterstock.


Gender-affirming hormones have a rapid and dramatic impact on physical performance


Trans women who use GAHT are prescribed oestrogen on its own, or oestrogen with a testosterone blocking medication (anti-androgens). Using GAHT, it is possible to reduce an individual’s testosterone blood levels and increase oestrogen blood levels to within the cisgender female range.


Trans Health Research and collaborators have recently published two articles that review the research on the impact of GAHT on trans sporting participation and physical performance. The research shows that when testosterone blood levels are reduced and oestrogen levels are increased, this affects muscle, fat mass and other aspects of the body that factor into physical performance. In nonathletic trans women, GAHT increases fat mass by approximately 30%, and decreases muscle mass by approximately 5% after 12 months, with ongoing decline beyond 3 years.


One thing that GAHT cannot change, once a trans woman has been through testosterone-dominant puberty, is bone structure. Trans women are on average, taller and broader than cisgender women. However, with the effects of GAHT on muscle and fat mass, taller and broader does not necessarily equate to a performance advantage.


For example, trans athlete Hannah Mounsey described her experience of GAHT:


“... it’s massive. I lost 20 kg in the first month I was on hormone treatment, simply due to the lack of testosterone. This obviously slowed significantly because the body doesn’t want to lose muscle, but the effects on my central nervous system and hemoglobin levels, things people can’t see, continue at a much faster rate. The central nervous system plays a huge role in strength and force production, while hemoglobin impacts your endurance capabilities. What this means is that essentially the external doesn’t necessarily match the internal. As the saying goes, don’t judge a book by its cover.” 

 

A person kneeling and holding a baton during a relay race

A person kneeling at the beginning of a relay race. Credit: Braden Collum via Unsplash.


Trans women have minimal to no performance advantage over cisgender women


In our review article we outline the currently available research comparing nonathletic trans women and cisgender women on performance measures. The research shows that after 2 years of GAHT, trans women appear to have little to no advantage over cisgender women in a 1.5 mile run and sit-ups, and by 4 years of GAHT there is no performance difference between the two groups. While push-up performance declined in trans women once starting GAHT, they still maintained an advantage over cisgender women. While absolute lean mass remains higher in trans women, relative percentage lean mass and fat mass (and muscle strength corrected for lean mass), hemoglobin, and VO2 peak corrected for weight was no different to cisgender women.


A more recently published study found that trans women athletes had higher absolute handgrip strength but lower lung function (FEV1:FVC), lower relative jump height, and lower relative cardiorespiratory fitness, compared to cisgender women athletes. This is a cross-sectional study giving a snapshot in time and suggests that trans women may perform worse than cisgender women in sports that require fitness.

 

It is difficult to tell how applicable these different performance measures are when it comes to sport. Different sports require different combinations of physical capabilities. Upper or lower body muscle strength, hand grip strength, endurance, power, flexibility, hand–eye coordination, communication with teammates, mindset, and strategy may or may not be relevant. While the slight advantage that trans women have over cisgender when it comes to push-ups might be relevant in swimming, for example, how relevant is it to soccer or cycling?


Another issue with the current research is that most of it is of low quality, typically involving only small numbers of people, with few long-term studies. We really need higher quality, larger and longer studies in order to be confident in the science.


Aside from research, the absence of trans women dominating women’s sport is also evidence for the lack of performance advantage. For example, in the 20 years that trans women have been allowed to compete in the women’s category at the Olympics, only 2 openly trans women have competed, and none have medaled. 


 

A trans woman stretching in a gym

A trans woman stretching in the gym. Credit: Yuya Parker via Adobe Stock.


Trans women are required to meet strict criteria to compete in elite-level women’s sport


Most international sporting bodies have eligibility guidelines for trans inclusion. Typically, trans women who want to compete in elite-level sport must meet strict criteria related to the time they have been on GAHT, their sex hormone levels, and specific performance measures.


For example, the Australian Football League Gender Diversity Policy for Elite Football, stipulates that trans women are eligible to compete in the women’s category, provided they demonstrate their testosterone blood concentration has been maintained at below 5 nmol/L for at least 24 months. Additionally, they are required to provide as much data as they have from the previous 24 months on their height, weight, bench press, squat, 20m sprint time, vertical jump, match raw GPS data from three Australian Football matches, and 2km run time. All of this data is used to assess whether the trans woman has any relevant and significant competitive advantage compared to cisgender players. There is also assessment of safety risk of the trans woman’s potential participation – considering the safety of both her and other players.


Recently, some sporting bodies have implemented bans that prevent any trans women from competing in the women’s category. However, these ‘blanket bans’ are not based on evidence (given there is no definitive evidence that trans women on long-term GAHT have a performance advantage over cisgender women) and do not recognize that trans women are as diverse as cisgender women when it comes to their height, weight, and various other factors that may impact physical performance.


 

 

A trans woman half-standing above her BMX bike

A trans woman with her BMX bike. Credit: FOTOGRAFIA INC. via iStock.


Community-level sport is for everyone


When talking about who can play sport, it is important to make a distinction between elite level and community sport. Whilst guidelines should be in place for the participation of trans people in elite sport, the line distinguishing community sport and elite sport is at times difficult to define and may be different for individual sports or disciplines. Sometimes rules and policies made at the elite level have trickle down effects to community sport, even if this is not the intention of the policy.

 

Participation in physical activity and sport are deeply ingrained in Australian society. The immense benefits of engaging in sports and physical activity go beyond just physical health and extend to mental and social well-being. Community sport at the grassroots level is all about inclusion, community/social connection, fitness, fun and which should be welcoming of everyone, trans people included.

 

In Australia, the inclusion of trans people in community sport is covered by the Sex Discrimination Act 1984 which prohibits unlawful discrimination on the basis of sex and gender identity in certain areas of public life. In 2019, the Australian Human Rights Commission and Sport Australia released the Guidelines for the inclusion of transgender and gender diverse people in sport, which provide clear guidelines for sporting bodies and highlight the need to centre the wellbeing of trans people in any policy development process.

 

Most Australian sporting bodies have clear guidelines regarding the inclusion of trans people in community sport. For example, in comparison to strict criteria for trans inclusion in AFL Elite Football outlined above, the Australian Football League Gender Diversity Policy for Community Football states that: “... in Community Football, considerations of social inclusion have greater priority than concerns that may exist with respect to competitive advantage in relation to the participation of gender diverse players”. Under these guidelines all trans women are eligible to compete in women’s Community Football competitions, with a clear process to address any unacceptable safety risks to either the trans player or other players.


 

A trans woman sitting on a couch, looking sad

A trans woman sitting on a couch, a sombre expression on her face. Credit: Yuya Parker via Adobe Stock.


Trans women still face significant barriers to sport participation


Even with guidelines in place to facilitate trans inclusion in sport, trans women still face significant barriers to participation. Many trans women have had previous negative experiences or anticipate discrimination from coaches, officials and other players, and bathroom/changeroom facilities may be inadequate for trans people, in terms of providing privacy and safety.


Because of actual and anticipated discrimination, trans women participate in sport at lower rates than cisgender women. At an elite level, there are very few trans women.


There is clearly a lot of work to be done to improve the inclusion of trans women (and all trans people) in sport, at both an elite and community level. In many respects, Australia is leading the way. For example, in addition to the Australian Human Rights Commission guidelines and the growing number of sport-specific trans inclusion policies, there are two national sporting inclusion programs designed to assist sporting organisations with the inclusion of people with diverse sexualities and gender - Pride in Sport and Proud 2 Play.


In terms of research, in a world-first, The Institute of Health and Sport at Victoria University and Trans Health Research are currently conducting the GAME Study, which aims to uncover the effects of GAHT on skeletal muscle health, fitness, and performance. High quality research, like the GAME Study, is vital in improving trans inclusion in sport.  

 

 

Authors:


Dr Sav Zwickl (they/them) is a trans non-binary Research Fellow with the Trans Health Research group. They have a Masters degree in Sexology, a PhD in Gender, Sexuality and Diversity Studies, and experience in LGBTIQA+ peer support.


Eli Ward Smith (they/them) is a PhD Student with the Trans Health Research group, and a critical care registered nurse and senior research officer, with a background in psychology. They are trans non-binary and active in rainbow family and LGBTQIA+ community advocacy spaces.


A/Prof Ada Cheung (she/her) is an Endocrinologist at Austin Health and a NHMRC & Dame Kate Campbell Research Fellow at The University of Melbourne.

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