Originally Posted by Bacciagalupe

It may well give them better power transfer under high wattages. But no one appears to released any data, or quantified the difference.

I would also guess that if frame flex does make a difference, most new race bikes are all in the same range of stiffness. There could be a huge leap from an 80s era straight top tube frame to a Giant Propel, and very little difference between a CAAD8 and a Propel.

I'd also point out that sprinters were sprinting long before they had today's über-stiff frames. I have no idea of the differences in speed or tactics due to frame stiffness, but obviously they could do it.