In my opinion, the best thing to improve support for larger-chested ladies who participate in high intensity activities is to wear two sports bras. In the absence of that, I've found the Fiona bra's support & coverage is quite good for me. (I'm a size 36D, 46 y.o.)
I ordered the 32DD in black and love it! I tend to struggle to find bras in general and sports bras it's an even bigger struggle. This one is REALLY supportive and pretty. I no longer have to put up with the bouncing and stares while I do Zumba.
Nor sure why this is advertised as med. support because it works great for high-impact workouts.
After other women raved about this bra, I had to try it for myself! I'm small chested so I had never worn a sports bra with a back closure (only pull over your head kind). This one is so comfortable, Ive worn it on 10+ mi runs and all day with my active wear. Plus, the adjustable front straps will be perfect for nursing!
This is the one. I have been searching for awhile and I finally found one that fully supports. The price is fair too. At first I ordered 36dd, which is my regular bra size. The dd fit but did not give me the right supportive feel I was looking for. So I tried it again in 36d, and adjusted the straps to tighten it up. There is barely any bounce. Very happy customer here :)