Originally Posted by Gavin Harrison
I can pop my knees fairly frequently like that, but not much while squatting, without any load being applied to them by flexing them. My doctor just thinks I'm loosely jointed, so I've never worried about it. I usually flex my knees to about 90º before I get under the bar just to loosen up my quads a little before squatting anyway, that might help. Also, I squat just bellow parallel (maybe 1-2 inches), not of to rock bottom.
I'm very much like this. Sometimes they'll pop under load (especially at the beginning like the above video), but usually not. Without anything on my shoulders they will pop every time at this point guaranteed. But it doesn't hurt and hasn't for over a year of them doing this, so I don't bother with it. I just try and prepare people that I might be working out with because I know it is one of those sounds that most don't want to hear.