>despite the aid of a shoe that designers say will make runners 4 percent more efficient. Seems like this could be a big factor. A shoe itself acting as a spri

>despite the aid of a shoe that designers say will make runners 4 percent more efficient. Seems like this could be a big factor. A shoe itself acting as a spring and helping the runner make bigger strides with the same effort. I won't be surprised if the official race wouldn't allow these "enhanced" shoes.