i believe squats and weight lifting in general are great for staying healthy, incl. your joints, as long as you
- keep proper form
- give yourself time to recuperate and don't overtrain
- have a clean, nutrient rich diet, complemented with supplements
(vitamins, minerals etc.)
- don't mess with drugs
Like cytix previously mentioned, weightlifting in a duly manner will actually strengthen the joint and surrounding connective tissue. Be sure to work all muscles crossing over the joint to prevent imbalances which could lead to injury later on.
I think they strengthen the knees tremendously when done with proper form. I went over the high side on the bike this summer and believe I would have torn that knee apart if it wasn't so strong. Hell, it would have killed a mere mortal!
also, I had a women there (shes a personal trainer) watch me squat to see if im doing it right. She said it was picture perfect. So i guess im doing them right
i have been doing squats for a number of years with no problems i used to use the leg press on occasion but a few times i noticed slight pain in my knee area perhaps a slight strain on the ligaments or muscle surrounding the knee ... but i find squats are a natural movement for me and i enjoy doing them immensely .. so far so good no probs.