The arrival of the new Adidas Boost has created quite a stir amongst runners and the running industry. Adidas have even gone as far as describing their new Boost technology as ‘a running revolution’, and that ‘running will never be the same’ – But what is this new magic technology, and is it really a ‘running revolution’?
Traditionally, the majority of running shoes were constructed using a midsole made out of EVA (ethylene vinyl-acetate), which is an extremely elastic material that can be sintered to form a porous material similar to rubber, yet with excellent toughness. These characteristics made EVA the perfect material to provide runners with a cushioned, lightweight and flexible shoe.
However, the truth of the matter is that although EVA is very well suited as a midsole material for running shoes, it did have its limitations. Firstly, in order to increase the cushioning it provides it has to be made much softer, thus it become less responsive, and vice versa, the more responsive you want the shoe to be the harder the EVA had to be made. Secondly, its lifespan, which some runners would consider to be on the short side; most manufacturers recommend that an average road running shoe should last a runner between 500-600 miles.
This is where the Boost technology comes in – a material that offers greater cushioning, superior durability but is still as lightweight and flexible as EVA. So what is it?
The Boost technology is formed from TPU (thermoplastic polyurethane), an elastomer, which possesses high abrasion resistance, high levels of flexibility and ranks as one of the best materials for load-bearing capabilities. If you delve a little deeper you may notice that this new magic material used in the Boost is not new at all; it has been used for years in objects such as cycling helmets, in-car headrests, and medical appliances. Therefore, the revolution is not the material itself, but rather the way in which the material has been applied.
In applying this new material to a trainer Adidas have focused their efforts on the concept of energy return. When the foot of the runner hits the ground, energy is lost as it dissipates as heat, noise and vibration – If that energy can be stored and returned it creates greater efficiency. This is where the Boost’s TPU capsules come into play; the each little bubble that gives the midsole its polystyrene look is designed to store energy released and hold onto it and release it to assist each stride.