I have an issue with my squatting;
Although I keep my lumbar spine in extension and my weight back on my heels, I find that my torso leans forward a fair amount past 45 degrees, it is not so bad with bodyweight only movements, however under load I find my chest moving closer and closer to the floor, it is quite funny to see:-)
I do find though it limits my ability to push heavy as my lower back tends to tire a little, my lower back is prety strong from plenty of Romanian deadlifitng and the like.
I thought it maybe something to do with my dodgy knee not bending much past 90degrees, however I also have a client with the same issue with healthy knees.
Ta for now