As if needing a good support bra while running is not hard enough to find, try adding in the variable of a nursing chest size.  I found this bra at a local running store and when I tried it on I jumped up and down as crazily as I could - and NO PAIN!!  Everything stayed jiggle free!!  I was so excited!  After six months of nursing, the bra is still a champ.  Since I am exercising more, I just ordered another.  The bonus is the way the straps adjust, really easy and always supportive whether I just nursed or I was fully engorged.  If it can support my nursing chest I think it can support yours too.  :)