My size 12 is 0.7 oz lighter than v3 and more than a full ounce lighter than the original 4%. Thomas Hengge The Vaporfly 4 has a heavily sculpted midsole, which helps to reduce weight.

A 4 percent boost in running economy means that a marathoner usually capable of running a 2:05 race should be able to slip on a pair of Nike's shoes and run pretty close to a two hour race, no ...