Adidas’ Futurecraft division has been running for a few years now, trying to find new ways to build footwear. Its 4D midsole demonstrates how 3D-printing could revolutionize the way footwear is made, while its Loop is made from entirely-recyclable materials. Now, the sports company thinks that it’s found an even smarter way to make uppers that are lighter and stronger than ever before. The Futurecraft.Strung (sorry, STRUNG), is a proof-of-concept sneaker with an upper made from individually-wound threads.
Adidas says that it has developed a custom-built robot that can weave threads diagonally across the midsole. The fact that the shoes are assembled by robot -- something Adidas has plenty of interest in -- means that each thread of raw yarn can be intentionally placed.The strings are color coded: Red threads are stiffer and stronger, locking your heel in to prevent slip and toughening the toe-box and midfoot. More supple Yellow threads are used in the forefoot for added flexibility.
The easiest way to understand how Strung works is to think about lacemaking, since every individual thread is pretty weak. Put them together, however, and the resulting construction is far stronger, and it’s a similar principle at work here. Adidas has cooked up a new manufacturing process to wind individual threads across the midsole to create strength without weight. It also helps reduce the amount of material needed and the company claims there’s almost no waste involved in the making.
For Futurecraft fans, the biggest news is the reduction in weight, since Adidas is saying that the Strung prototype weighs 220 grams (7.7oz). That’s not particularly light compared to a typical running shoe, but the 4D midsole has a reputation for being heavy. The 4D Run 1.0, for instance, has a quoted weight of around 366 grams (12.9oz).
Certainly, nobody at Adidas is going to start talking about the Vaporfly-shaped elephant in the room. The Nike-made trainer has a carbon-fiber plate running through the midsole that, Nike says, makes energy savings of around 4 percent every time your foot strikes the ground. They have been described as “mechanical doping” by experts, and were used by Eliud Kipchoge to run the first sub-two hour marathon.
Adidas is, at least, making no bones about pitching Strung, or whatever version of Strung reaches the world, at road runners. The company said that it was targeting athletes looking to make times of five meters-per-second or faster. That would, surely, point to the sort of elite road runner looking to compete in serious competition. And the new 4D midsole lattice design is designed to cater to fore-foot strikers -- better for speed, worse for energy efficiency.
Right now, Strung is just a concept, and it looks like Adidas wants to build a range of Strung shoes for different sports and runner profiles. The company says that it’s the first “Coded” product, tweaked to suit a specific athletic profile, which should mean other styles will also be catered for in future. The first shoe will be, circumstances-permitting, available at some point in late 2021 or early 2022 for an as-yet undetermined price.