I got a 38C and expected to at least while walking not "To bounce up and down"  which sadly I did.  I was expecting as a Sports Bra and having used Champion products in the past  I could perhaps do some mild exercise (other than the walking"  without feeling as tho not wearing a bra at all flopping away.  The cup size was fine.  Instead of returning I gave to my housemate which in turn fit her perfectly as a sports bra.  She wears the same size just not the cup size.  Extremely disappointed