I am an avid trail runner and I am used to running on pretty rough terrain with my camelback. It doesn't really bounce if you snug it up all the way although it does take some getting used to at first. I do not recommend the chest strap. I have a camelback with the strap and I never use it. I have a muscular chest and if I snug it up, even a little, the strap it feels constricting. I can't imagine how it would feel if I was female. It is definitely better than bottles. Give it a month and you will forget that its even there... until you need a drink.

I am an avid trail runner and I am used to running on pretty rough terrain with my camelback. It doesn't really bounce if you snug it up all the way although it does take some getting used to at first. I do not recommend the chest strap. I have a camelback with the strap and I never use it. I have a muscular chest and if I snug it up, even a little, the strap it feels constricting. I can't imagine how it would feel if I was female. It is definitely better than bottles. Give it a month and you will forget that its even there... until you need a drink.

Yes it will bounce.It's worth getting the Camelbak Rogue (men/universal) or Dream (Women) for the cross-straps.http://www.backcountry.com/store/CAM0222/CamelBak-Rogue-Hydration-Backpack-21L.htmlhttp://www.backcountry.com/store/CAM0226/CamelBak-Dream-Hydration-Pack-21L-Womens.html