One thing to note and I guess might be a bit of the puzzle is that the data clearly indicates that trans-gendered men have lower upper and lower body strength compared to cis-men, while the opposite scenario (transwomen compared to cisgender women) appears much less conclusive.
The trans-women vs cis-gender strength effects are heavily influenced by a single study. There are only 7 studies for upper body strength, 5 of which lean towards showing greater trans-women strength, 1 that leans towards reduced, and 1 (Alvares 2025) which clearly indicates reduced strength. Similarly for lower body strength there are only 4 studies with a similar pattern (once again, the Alvares 2025 producing the clearest TW weaker than CW effect).
The Alvares 2025 study compares amateur volleyball players. There are 7 trans women in that study versus 8 cis-gender women. Average hours per week of activity (or volleyball? Unclear, I'm working off the meta-review's summary table) is 4 for TW and 14 for CW. Average age is 30 (28-33) for TW and 26 (22-29) for CW.
I don't think that makes the Alvares study useless, but I do feel that it's deeply limited. 4 hours vs 14 hours a week is a pretty big difference in activity level.
> While transgender women exhibited higher lean mass than cisgender women, their physical fitness was comparable. Current evidence is mostly low certainty and has heterogenous quality but does not support theories of inherent athletic advantages for transgender women over cisgender.
I don't find this study especially interesting or pertinent on the subject of sports advantage, as it only covers a small number of possible Whys, but doesn't touch Whats. It would be more useful for researchers to compare actual sports performance. For obvious reasons, these studies are probably not available for metaanalysis.
Like, for example, is the individual in question currently on HRT? When did they start HRT? What is their current testosterone levels? And when we dive into a specific sport, how do they actually perform?
The issue is that for any given sport there's like 1 or 2 transgender people participating in it.