They couldn't prove the 5%, apparently they are more like 4.4% to 4.5% which would be stupid to name them after.
Nah but seriously, the shoes are overrated. It's an extremely smart marketing campaign from Nike to make you believe they make you so much faster, where in reality they barely make you any faster than the Adidas Adios for example.
The number one thing in shoes that makes you faster is lower weight. They are much lower weight than the average marathon shoe, so of course people are faster. But if you compared them to other good, light marathon shoes like the Adios, the difference becomes very insignificant.