The international governing body for running sports on Friday cleared the way for competitors at the 2020 Summer Olympics in Tokyo to wear Nike's controversial VaporFly shoes, which have been shown to make runners faster.To buy more NIKE FREE 5.0 with cheap price, you can visit shoesnewest official website.
Some distance runners say the shoes, which have been on the market since 2017, are helping to advance the sport of running. Others contend they confer an unfair advantage. World Athletics — the sports governing body formerly known as the IAAF — has now weighed in, issuing new guidance on what's permissible in the technology in elite runners' shoes.

The guidance stipulates that the thickness of a shoe's sole may not exceed 40 millimeters. It also limits to one the number of carbon fiber plates allowed in a sneaker. The VaporFlys have a 36 millimeter sole and a single, full-length carbon plate designed to prevent energy loss, according to Nike. The carbon fiber plate is a "built-in secret weapon" that delivers "a propulsive sensation, for speed with every stride," the sports apparel and equipment maker says on its website.

World Athletics president Sebastian Coe, a four-time British Olympic medalist, said in a statement that "it is not our job to regulate the entire sports shoe market, but it is our duty to preserve the integrity of elite competition by ensuring that the shoes worn by elite athletes in competition do not offer any unfair assistance or advantage."

The amended rules also require that beginning April 30, shoes worn by runners in competition must have been commercially available for at least four months. This effectively blocks Nike rivals that are developing similar technology from manufacturing shoes that will appear in competition at the upcoming Olympic Games. The VaporFlys have lit up the running scene, both with their bright colors and the controversy surrounding the supposed advantage they give runners. When Kenyan long-distance runner Eliud Kipchoge broke the milestone two-hour marathon barrier in Vienna in October, he was surrounded by a team of pacers sporting bright-pink VaporFlys. Kipchoge wore a prototype Nike sneaker that does not meet World Athletics' competition standards. Subsequent research found that the shoes can make runners 4% faster.