Just wanted to let you all know of a KILLER ham exercises.
Stand in the smith machines. Place a bench behind you. Then move one leg far infront of you as if you are doing a lunge and put the other feet behind you on the bench and then do squats like that. I can realy feel my hams when pushing upp in that exericse. It toasts my hams incredibly well without involving lower back like in straight leg dl. It is very knee friendly to.