I've never had any pain in my knees when doing squats, deadlifts, snatches, etc. But I've noticed some strange feeling cracks/tension some times which worries me cuz its really important that I keep my knees in good shape. Other than stretching the hams, glutes, calves, flexors,etc. anyone know any good knee 'prehab' exercises that are good for the joint itself and/or increasing ROM??