This is a new Brazilian study
bjsm.bmj.com/content/early/2022/09/01/bjsports-2021-105400.info
Cardiopulmonary capacity and muscle strength in transgender women on long-term gender-affirming hormone therapy: a cross-sectional study
Leonardo Azevedo Mobilia Alvares, Marcelo Rodrigues Santos, Francis Ribeiro Souza, Lívia Marcela Santos, Berenice Bilharinho de Mendonça, Elaine Maria Frade Costa, Maria Janieire Nazaré Nunes Alves, Sorahia Domenice
Conclusion
In this small cohort of non-athlete TW, who were previously exposed to male pubertal development and underwent long-term oestrogen therapy, we identified higher grip strength and VO2 peak levels than in non-athlete CW, but these same parameters were lower compared with non-athlete CM.
These findings add new insights to the sparse information available on a highly controversial topic about the participation of TW in physical activities. Future studies involving transgender athletes that account for and quantify variable exposure times to pubertal development and assess muscle cell metabolism are needed to elucidate the effects of long-term GAHT on TW sports performance.
and this commentary from Ross Tucker (sorry no formatting)
From Ross Tucker on this study above:
Over a decade (14.4 yrs average) of T-suppression, and TW have VO2max 20% higher, grip strength 19% higher & skeletal mass 40% than women. More evidence that male biology persists long after T is removed. Another piece of the same puzzle, albeit from a cross-sectional study.
The cross-sectional bit is important - the study hasn't (like over a dozen others) tracked people from Day zero onwards, so the differences are a 'snapshot' rather than a 'movie', if that makes sense? Means you don't know how those TW began, 14.4 yrs earlier, but the finding of quite large differences compared to women (20% or more) is striking, because a) they either began as typically representative of males, and lost some, but retained significant advantages vs women, or b) they began well below men, and lost hardly any advantages. In either case, the end point, over a decade later, is biological differences compared to women that will create performance implications. Of interest, the mass retention and VO2max advantage mean that relative VO2max (ml/kg/min) ends up similar, which means in some sports (weight-determined) the performance implication may differ - sometimes very large, sometimes smaller, as in some categories within endurance sports.
But zero? Unlikely, because cardio function, FFM & strength are greater. Important paper, showing striking biological 'persistence' 14 yrs on.
Two further thoughts on the study. First, the TW vs women differences in muscle mass and strength remain large (20%) after more than a decade of T suppression. One year vs ten, biology "persists". Second, add training to the mix and TW and women would obviously get stronger.
You could TRY to argue that women would get stronger relatively more than TW (you'd have a job on your hands to explain why this would be, but anyway). More likely is that the differences - TW vs women - would persist or even increase with the addition of training. What this study confirms is that non-trained TW retain biological differences with performance implications after 14 years of T suppression. You'd have to believe that W could make up these gaps with training to believe in fairness in sport. That is, trained W = non-trained TW = fair!
(all that was from Ross Tucker)