It's gonna jiggle no matter what. If they really move about a LOT it might cause some strain and soreness. Get a better sports bra or, as I've seen some top heavy girls do, wear two + a tight a vest. Us guys joke about these things (cos it's fun) but our 'bits' can also sometimes need restraining when we go out for long runs and support, of the right kind, makes all the difference (properly fitting jocks in our cases).