This bra does a great job!  I did have some issues with sizing and had to send back two before finding one that fit correctly. (meaning that I could jump or run without pain) I usually wear a 38DDD in a standard bra.  My suggestion if you have large breasts is to order this a size smaller.  I ended up with a 36 DD and it really does hold everything still.  Under a shirt, you can still tell I have two breasts.  They are quite compact and "spill" a bit out of the inside cups but the outside "top covering" keeps them all together in appearance.  I am hoping that as I continue exercising they will shrink a bit so they fit in the cups better.  SO.. my suggestion to really hold large breasts still for exercise (for women with natural breasts... idk about surgically altered) would be to go down a band size and cup size.  It IS rather binding and I wouldn't wear it out if I wasn't exercising but it does it's job which says a lot for a large breasted woman.