I know, lot's of peeps have bad knees. Two car accidents when young, now I'm not-young and professionals say I will eventually need new plastic knees or whatever. Walking, I'm fine. Getting up or lowering to a chair is painful. I've found a little information in MDA forums about people with knee issues, but I have not found info specifically about substitue exercises for squats and jack knife/dive. Can anyone suggest ways to work the quads, gluts without having to work the hinge of the knee? Is it possible? and thanks for any info.