This bra got me out running for the first time in 20 years. 34F is not an easy size to find, but I'm so glad I took a chance on this bra. There is still some bounce, but it is greatly reduced, and it strikes a good balance between comfort and bounce reduction. I have very dense, heavy breasts, and tend to want ZERO bounce. Never going to get it (unless I wear the bras where you can't expand your diaphragm and you have to breathe in tiny sips -- not feasible!), but this bra comes VERY close.