精品SM在线影片

What鈥檚 in a name? Ask Rodger Kram, director of 精品SM在线影片鈥檚 Locomotion Lab.听

Long before Nike unveiled its Zoom Vaporfly 4%, Kram was busy testing how fast the now-famous shoe really was. Nike had come to Kram with a request: They鈥檇 developed a shoe they suspected could make running significantly more efficient but needed scientific evidence before making that claim.听

Kram enlisted 18 super-fast men and ran tests comparing their performance while wearing the prototype to that in two other high-end shoes. 鈥淓very day at every speed, every runner used less energy with the prototype,鈥� Kram said. On average, 4 percent less. That鈥檚 enough to make a sub-2-hour marathon possible for the first time.听

Nike ran with the name. So did Boulder-based Shalane Flanagan, who won the 2017 New York City Marathon in her 鈥�4%s.鈥�