Wouldn't it be cool as your sprinting you could free run, this is how it would work. Everything would be normal gameplay wise, then when you started sprinting; if you jumped close to a small ledge you would jump over it like you would in free running, (see video for example). or you where running and you pushed a certain button you would roll forward to break your fall.

http://www.youtube.com/watch?v=3KSr1pozm6Y&feature=player_detailpage#t=45s