I'm barely a B, but I still have to wear a sports bra to ride. Anyway, I read somewhere that sports bras for an A or B can be the "Flatten them into your chest" kind - the ones that don't have cups. But for women bigger than a B, you really need the kind with cups - and of course the high impact, etc. like everyone else said.
Yeah, good times being a girl. I trail ride with a bunch of guys and I hate how much more challenging it is for me to pee out on the trail. That combined with the boob thing - proof, once again, that we are tougher!
I was normal...then I got a horse.