I have heard about this from someone else, that as your muscles change you do indeed get more flexible. I am pre-hrt at the moment and am working on gaining back some flexibility that I had when I was younger and it is very difficult. I hope that I get some flexibility after awhile on hrt.
Bra straps, HAH, I can UNDO them, but I can't fasten them from behind. I suppose like most things with transision, YMMV.
-Julie