Squats are fine for the knees, it is all in the stance, execution, and with heavy loads, the shoes play a role, use something flat like Chuck Taylor's so you aren't pushed forward......running is not bad for the joints either.......people who say this either squat with bad form, or they have pussy-itis and are afraid to squat or they don't wanna get in running shape.......of course so as not to offend, this doesn't apply to people with a pre-exsisting injury making it difficult to do either or both.