There are a lot of anatomical advantages of having a man's body, even if Fallon has been chemically re-adjusted, it may diminish her muscles to an extent, but it doesn't shrink her man hands, man feet, shoulder width, bone density and other structural advantages the average man's body has over the average woman's body.
Renee Richards was a well known transgender man who competed in women's tennis back in the 70's-80's, but his/her strength, speed, height & size advantages weren't translated to throwing concussive blows at her opponents. I think that's the biggest variable. Fallon isn't winning a running race, tennis match or basketball game, she's throwing her man body parts against a women's face. That's just my opinion.