Ask Lemmy

Gender-affirming care massively reduces the difference, but transwomen are still likely to be faster than AFAB women:

Prior to gender affirming hormones, transwomen performed 31% more push-ups and 15% more sit-ups in 1 min and ran 1.5 miles 21% faster than their female counterparts. After 2 years of taking feminising hormones, the push-up and sit-up differences disappeared but transwomen were still 12% faster. Prior to gender affirming hormones, transmen performed 43% fewer push-ups and ran 1.5 miles 15% slower than their male counterparts. After 1 year of taking masculinising hormones, there was no longer a difference in push-ups or run times, and the number of sit-ups performed in 1 min by transmen exceeded the average performance of their male counterparts.

But what season you're born in also influences your strength and fitness:

There were significant main effects of birth-month for cardiorespiratory fitness (F=4.54, p<0.001), strength (F=6.81, p<0.001) and power (F=3.67, p<0.001). Children born in November were fitter and more powerful than those born at other times, particularly the summer months (April, May and June). October-born children were stronger than those born in all months except September and November. This relationship was evident despite controlling for decimal age and despite no significant inter-month differences in anthropometric characteristics.

So maybe it's not fair for all those poor summer babies to compete against unfairly blessed autumn athletes?

Gender affirming surgery for trans women often includes bone shaving in various locations because your skeleton does not substantially change in response to your hormones. Hormone treatment does not affect your skeleton.

Also, in the same way that it is easier for people who have lost weight to put that weight back on because they already have those extra fat cells, people who lose muscle mass will have an easier time gaining muscle back because they already have those extra muscle cells.