You are trying to do dynamic carve turns? I have similar problem only when my boot is tight. If I loosen up the top laces of my boot, then I can bend my knees easier. But, the support is not as good for really hard carves. The problem may be that you are not throwing your weight over your toe edge enough while trying to keep your body stationary. That requires bending knee and ankles and it is hard to bend your ankle when you have a stiff boot. So try to loosen your top laces just a tad bit (that's what I do). You have to bend your ankle first inorder to distribute your weight to your toe side, bending the knee alone will only throw your weight to your heel side. By loosening up the top laces, you allow your shin to be pushed forward more and bending your ankles. Just don't loosen them up too much.
Last edited by yusoweird; 02-14-2010 at 12:01 PM.