Nike athletes Shalane Flanagan and Amy Cragg were presented with the prototypes of the Nike Zoom Vaporfly 4% in January 2016, just before the marathon trials for the Rio games. Both were initially hesitant, with Flanagan concerned about the "big lift," and Cragg expressing skepticism at a concept she worried was "gimmicky." Their worries were quickly dispelled the next morning during a 20-mile run, in which they discovered they were able to maintain their form longer while feeling fresh. Both have subsequently set personal records while wearing the Zoom Vaporfly 4%.

Nike has been working on the shoe's tooling since 2013, which features new Nike ZoomX foam that's ultra-lightweight and soft, providing up to 85-percent energy return. There's also a full-length curved carbon fiber plate embedded within the foam, which increases stiffness for a sensation of propulsion, ultimately resulting in a 4-percent improvement in running economy as compared to the Zoom Nike Streak 6 (currently Nike's fastest racing flat).

The Nike Zoom Vaporfly 4% hits select retailers and nike.com on June 8th.

Release Date: 6/8/17 (Thursday)