OREANDA-NEWS. To keep physically fit, more and more people jog for miles, across fields and along roadways. You can go running just about anywhere. All you need is comfortable apparel and a pair of running shoes. The global sports equipment industry is profiting from an increased enthusiasm for running: Worldwide, runners spend an estimated EUR 15 billion on their equipment. Customers place top priority on good footwear. Even people who only go jogging occasionally now look for lightweight soles that provide optimal shock absorption and enhanced running comfort.

Today’s sports shoes are genuine high-tech products compared to previous versions: The many different materials used to manufacture the shoes make them lightweight and stable. These materials enable the shoes to be tailored precisely to suite the style of running, the customer’s expectations and the various running disciplines. All this can be confirmed with a look around the development laboratories of sports shoe manufacturers: Test subjects run over sensitive pressure measuring plates which analyze and evaluate every step. High-speed cameras film the movement patterns and the heel-to-toe motion of the feet in the tiniest detail. All this information goes into the subsequent shoe design, which enables athletes to achieve new personal bests – and also offers recreational runners optimal running conditions.

Manufacturers are permanently on the lookout for cutting edge technologies and innovative materials. adidas is also constantly further developing its running shoes. The company, headquartered in Herzogenaurach, Germany, has been supported by BASF materials experts for more than 20 years. Using BASF’s new foam Infinergy™, adidas has now developed the Energy Boost, a thoroughly new running shoe with unique spring and cushioning properties. Its outstanding feature is the midsole, the central element of every running shoe. It is made from a new particle foam which absorbs the shock impact on the foot during jogging, while simultaneously cushioning the foot. The high rebound effect of the material provides the runner with an energy return not offered by any other running shoe.

For every midsole, adidas needs about 2,500 of these small beads. To convert them into the desired form, they are treated with hot steam, a process in which the outmost layer of the beads melts slightly, causing them to bond into a stable shape. The internal air cell structure remains unaffected by this process.

A midsole made from Infinergy can be compressed to an extreme degree: by about half of its volume at a pressure of two bar. This property is particularly effective in absorbing the shock impact on the foot. As soon as the compressive impulse subsides, the foam returns to its original shape at lightning speed. The sole therefore absorbs the runner’s energy, but then returns a large amount to the runner.

Very lightweight and elastic – these special properties make Infinergy a material with a wide range of applications. Some of these are currently in the trial phase (see info box on the last page). Others may still be a long way off, but are certainly feasible: in the future, BASF’s foam could, for example, make the “flat-less” bicycle tire that many cyclists are dreaming of become a reality. Infinergy is also potentially suitable as flooring for running tracks. For the automotive industry manufacturers, who are always searching for lightweight and robust materials, BASF’s specialty foam could also open up completely new opportunities.