You may also be walking faster. But yes too much bounce means the bras need replaced. Most bras can not provide support for more than about 6 months. Although if you get a fitted sports bra you can push it a bit. Or more than a bit, I had some of mine for well over a year and they only wore out because I wore them while preggo and I got waaaay to big for them
I find that any bra sized L, XL - whatever does not provide enough support for anything beyond strolling. (now if you are an "S" or maaybe an M thats different
)
I wear a sportsbra by Champion
http://www.championcatalog.com/cgi-b...y?prnbr=CH1018
I get the band size that matches my (professionally fitted) bra size and the cup size 1-2 cups smaller because I like lots of compression for running. Also, they dont MAKE my cup size with my band size.