Nike's newest innovation isn't so novel your great-grandmother wouldn't recognize it. In fact, the sportswear giant employed an age-old technique to solve a modern conundrum: how to create a lightweight shoe that fits like a sock but has the support of a trainer. Its Flyknit sneaker, which will debut in time for the London Olympics, uses both flat and circular knitting technologies to create a featherweight, formfitting, and virtually seamless upper. Even with Kevlar-reinforced filaments knitted in for structure, the upper and tongue weigh only 1.2 ounces. The entire shoe clocks in at an impressive 5.6 ounces for a size 9—19 percent lighter than the Nike Zoom Streak 3 worn by the first-, second-, and third-place athletes in the 2011 World Championships men's marathon.