Thanks so much ladies. I'm about a D at the moment but I expect I'll go back to a C when I finish BFing (although I have no time limit or expectations about weaning, so who knows when that will be ). I have to have absolutely no bounce, like I want them pressed as firmly against my chest as possible, while still being able to breathe of course.

Berlei & some other manufacturers make bras rated for different exercise so you will need to get the one rated for high intensity workouts. I also wear an exercise crop top over my bra for added support.
the things you learn when you ask Yeah, I was thinking of a really tight crop top as well as a bra too.

And thanks so much everyone for your lovely support *mwah*