I've started to go heavy on my atf squats and my knees started hurtings for 1-2 days after I squatted. Everybody whom I talked too said that your knees aren't suppose to hurt if your used good form.
This is what I did... I use a stance that is a little wider then shoulder width. I go down, pause at the bottom, then go back up. My knees never pass my toes and my back is straight.
Anyone else have similiar problems?