Originally Posted by Harold74

I've been researching and experimenting with the flat back thing in the months that have passed since making the comment that you quoted above. My current understanding is that the notion of an aerodynamic "flat back" is something of misnomer, as described in this article: Link. What competitive cyclists call a flat back seems to really be just a flatter back. The forward pelvic tilt gives the rider a head start in terms of levelling out the torso coming off of the saddle but some curvature of the spine above the pelvis is still required.