Actually, I don't like rotating my hips forward (which I naturally do) because it puts too much pressure on my delicate girl soft tissue. I focus on keeping my pelvis upright and well supported on the sit bones, and bending at the waist. Core class helped make that more possible. No, I am not perfect in this posture, but the closer I am to that position, the faster and more comfortable I am. It doesn't seem like a flat back to me, but it seems to work....

H&B
~T~