Elliott Heath, a Nike Running footwear product manager (author) says:
That comes down to the thicker stack of the shoes and being more efficient with energy storage and return. We’re never going to be able to return more than 100 percent of energy but we’re trying to get more and more efficient and closer to that 100 percent line. In terms of doing that, that comes down to a couple factors for us and a big part of that is the ZoomX foam underneath the foot. Not only is foam lightweight, but it’s also very good at returning that energy efficiently. And even better than any of our foams and other foams that exist in the market is the Zoom Air technology, which is even better at storing and returning that energy. So those two cushioning technologies come in together with the full-length carbon plate are essentially what makes up the magic and the engine of the shoe to improve running economy.
Why do they need to "return" any percentage of energy? Because it gets absorbed by a big ass piece of foam. So what's the solution? Less foam? No foam?
