Sorry, but there are plenty of postures between "bombing down a fast descent" and "I wish this were an easy chair." People should have options, but it's entirely possible for many people to ride a relatively relaxed road position and get around efficiently and safely.
Knowing what I do about biomechanics, I would rather have a slight arch through my thoracic spine (it is very rare to injure a disc in this region) than have the jarring on my lumbar spine from sitting straight up. In reality, I actually generally ride with a flat back and my hips rotated forward. I can tolerate a fair amount of pressure on my hands, so my erectors to not see an undue workload.
The average person should not experience excessive rounding in the low back, as they should not need such an aggressive position. If they put it there because pros do, that's their choice. The problem is with a "one-sizefits all approach."
Last edited by tadawdy; 11-23-11 at 01:14 PM.