I must say,
When I was going through stages of denial, I took up Freestyle Ninjutsu (before transition) I was very well built because of it. Well, for a guy anyway. I had a 6 pack, massive biceps and wow was I good at it. (My Sensei taught me more advanced techniques above the rest of the class, I was always teamed with the higher belts, and I was always used in the demonstrations) But yeah, when I woke up and realized just what I was doing, I basically stopped going. 2 Years later, I transitioned (Am female now ^_^) And on HRT, and with that, only 3 months into HRT, I weigh 72KG (158lbs) where as, before hormones, I weighed over 84KG (185lbs) all the weight that was lost was pure muscle (Gosh I love Androcur / Siterone [Cyproterone Acetate])
I now have a nice female look about me, lack of a figure though, and my breasts are developing quite well, I almost fill an A Cup, and have already purchased my B Cup bra which I will need soon, once my boobs start to stretch.
But yeah, long story short, If I needed to, I could pull off some of the techniques I know from my Ninjutsu, but really, I would not train due to taking Cyproterone Acetate which actually increases muscle recovery time by around 10 fold. I'd most likely damage a muscle if I did train now days.
I wouldn't recommend training in martial arts or anything that intensive whilst taking anti-androgens.

OMG Just realized, I write a story just about every time I reply to someone LOL!