Does NIKE'S Vaprofly really improve performance by 4%?

Created in conjunction with Breaking2, Nike’s attempt to enable the first sub-two-hour marathon, the Nike Zoom Vaporfly 4% was designed with the goal of helping the world’s fastest marathoners run their best. The tooling features new Nike ZoomX foam that is ultra-lightweight, soft and capable of providing up to 85- percent energy return. Shalane Flanagan wore this shoe and won the NYC marathon, the first American woman in forty years.

posted Tuesday November 28th