Trainers are no longer just shoes. The Adidas Ultra Boost and Reebok ZPump Fusion continue their transformation into high tech machinery for your feet.
The energy-returning concept pioneered by the Adidas Boost last year is back with the Ultra Boost. Sounding more like an engine than a shoe, it now boasts a 20% improvement in its “energy return,” or the spring you get from the compressible foam sole.
We tested last year’s shoe and the new Ultra Boost definitely feels bouncier, although we can’t really quantify whether it’s a 20% improvement. The shoe also feels faster, but is it? Strangely enough the scientific jury is still out. While the boost sole definitely feels like it puts a spring in your step its impact on the mechanics of forward propulsion are not as well understood.
But there are other reasons you’ll want the Ultra Boost. Firstly, the sole is made of around 3,000 cells of a special springy foam that compresses when you land on it, but then springs back, acting as a phenomenal shock absorber but still feels solid and not soft and wallowy. It’s perfect if you’re a heel striker, of course. And, as we discovered, if you’re carrying a leg or hip injury, the shock absorption in the Ultra Boost makes training much more comfortable.
Reebok’s ZPump Fusion takes a different angle to boosting performance. Rather than returning energy, it benefits the wearer by providing possibly the best fit of any running shoe on the market.
The original Pump was released way back in 1989, so this is the first major update of a technology that’s well and truly proven itself. The shoe’s one-piece upper has now lost all rigidity so that it moulds specifically to your foot once you pump air into an inflatable bladder in the shoe.
The result is a shoe that’s unique to the shape of your foot, with a custom fit so snug that the ZPump feels almost like it’s glued on. You get the sense your foot won’t slip or slide inside by even a millimetre.
The durability of the ZPump Fusion’s outsole has also been dramatically upgraded. The Z in ZPump is inspired by high performance ZRATED tyres on cars, so you’ll be able to put these shoes through their paces.