The World Cup’s just around the corner, and that means the shoe companies are now battling over whose stuff is more innovative. So while Nike is touting something called adaptive traction–something akin to cleats that retract on hard surfaces–Adidas is touting the lightest soccer shoe ever (which is going to be worn by Argentine star Lionel Messi).

Where the typical soccer shoe weighs about 10 ounces, the Adidas F50 Adizero tips in at 5.8. It’s a weird sensation to experience–picking them up feels like lifting a stack of mail. Crazy-light shoes, how do they work?

According to Adidas’s senior product manager, Aubrey Dolan, there’s actually a slew of high-tech breakthroughs at work. “You can always remove materials to make one lightweight sample, but mass-producing something for a mass market that actually functions is another challenge entirely.”

Almost all soccer shoes have a stiff insole board that keeps them stable. The F50 Adizero doesn’t have that at all–instead it simply has a molded poly-amide outsole they call a “sprint frame.” All the stability comes from the fins running across the middle of the footprint: