I am listening to the "House of Run" podcast right now with Alex Hutchison and he pointed out some interesting things- apparently, Adidas actually developed the carbon fiber plate with a curve (called the "Pro-plate") in it a number of years ago and testing at the University of Calgary said it gave them a 1% running economy bonus. Then they developed the boost foam, which gave them a 2% economy bonus.
Haile G ran his marathon world record in Adidas shoes with the carbon fiber plate, but without the boost foam. Hutchison said that Adidas stopped making the carbon fiber plate shoes because it was $2.50 more expensive to make and was cutting into their profit margins.
Any body else hear of this before?
It makes me feel like the Next% or 4% are much less groundbreaking than generally thought.