We now have research showing kg for kg trans women on GAHT are 19% weaker than cis women. Also research shows we are disadvantaged in any sport that requires endurance.
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A recent study found that trans women had lower lung function (FEV1:FVC), lower relative jump height, & lower relative cardiorespiratory fitness, compared to siswomen. This shows trans women perform worse than siswomen in sports that require fitness
May I ask what the practical implication of controlling for fat-free mass is? Is it basically a method of controlling for overall body size? i.e. if a trans woman is bigger she'll generate more power than a smaller cis woman, but if compared to a cis woman of equal size she'd actually generate less?
Estrogen supplementation greatly increases the total body fat percentage in trans women about 30% in the first 12 months. This results in reduced fat-free mass. Fat provides resistance for movement, as opposed to a muscle, which provides torque for movement.
Ah ok, so it's actually fat mass that is working against overall physical performance. Is there some reason far mass isn't measured directly but rather inferred from fat free mass levels?
A relatively unknown study from 2021 took strength data from eight trans women and eight matched cisgender males and females. It found that the measured strength of trans women was not as low as cis women, but nowhere near as high as cis men.
But when the strength of cis men & women was divided by their fat-free mass, they were equal. Conversely, when trans women's strength was divided by their fat-free mass, they were 19% weaker, kilogram for kg, than cis men and women.
Couple this with the reduction of the oxygen-carrying hemoglobin in blood to cisgender female levels after around three months of GAHT, and a trans woman's body will be significantly underpowered after a considerable period of such treatment.
A closer look at the data reveals that the cohorts are not matched & the main comparison is between fit/trained reference women & unfit transwomen.
So findings cannot meaningfully inform sports policy given they cannot be extrapolated to matched cohorts.
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https://bjsm.bmj.com/content/early/2024/04/10/bjsports-2023-108029
https://academic.oup.com/jes/article/5/Supplement_1/A792/6241278
https://academic.oup.com/jes/article/5/Supplement_1/A792/6241278
https://bjsm.bmj.com/content/57/4/e2.long?fbclid=IwAR2kVC0I0109kLi_gqEJplbnjP1pJbcjPUFy0pukVJBsbqNsEFCtFttygpY_aem_AUm2EhN_NezHpKkmO58IFqmaWeyPKFsxWN6ZXVBUVxhd-0vemuDSdW2DKJxVeDT2JY4
Based on this data, a cisgender male and a trans woman cannot be equated.
So findings cannot meaningfully inform sports policy given they cannot be extrapolated to matched cohorts.