Lately, I have been really working on my squat form as I have been moving up in weight. I have found that as I come up from my low point, I "contract" the arch in my back (actively flex my back straight). This seems to allow me to do more weight, puts the weight on my legs and less on the lower back, and makes for a more fluid movement. I have never heard anyone mention this before, is it good idea, or...?
And for the record, i am not one of those people that bends in half/leans forward at a damn near 90 degree angle when doing a squat.