Plastic foams are great insulators and great packaging materials. But they also have many other good properties - such as the specific stiffness of some types, good energy absorption, resistance to dynamic loads - that make them suitable for engineering applications. For example, special hybrid foams have been developed which can absorb the energy of a strong impact and therefore provide enhanced protection for the safety of car occupants in the event of an accident. And to preserve the durability of running shoes and their athlete-friendly properties, extensive tests have been carried out to determine which of the polyolefin cross-linked foams best serve this purpose.