Roller skiing is an off-snow equivalent to cross-country skiing. Roller skis have wheels on their ends and are used on a hard surface, to emulate . The skiing techniques used are very similar to techniques used in cross-country skiing on snow. First created as a summer training exercise, roller skiing grew into a competitive sport in its own right. Annual championships are held in various locations around the world. Most, if not all, national cross-country ski teams around the world roller ski during the off-season for specific physical training simulating winter skiing. In Norway, separate roller ski facilities have been constructed to allow exercise off public roads. History The first roller skis were built in the mid-1930s in Italy and North Europe. In the early 1950s, when cross-country skiing started to evolve to a serious competition sport, the necessity for good summer training grew. Starting in the 1950s people experimented with skis on wheels. In the 1970s, something of a standard emerged and the first races took place. At this time all roller skis had one wheel in front and two wheels at the back. The metal frame was between 70 and 100 centimetres (2'4" and 3'4") long. Athletes felt they could start to engage themselves in competitions. In 1976, Giustino Del Vecchio, an air pilot, established a record in Monza by doing in 24 hours on the roller skis he had designed, using material and technologies from the aircraft industry; narrow solid wheels with hard tread, reverse lock-up ball bearings to enable a forward push off the inactive ski. In the beginning, the skis were developed with one wheel in front and two wheels behind. The introduction of skating (free technique) in cross-country skiing changed athletes' training needs, which consequently impacted the design of roller skis. New roller skis with two wheels instead of three and much lighter materials could be used both for the classic style and skating. Competition The European Rollerski Federation was established around 1985, and the first European Championships were organized in the Netherlands in 1988. The growth of the roller ski sport attracted the notice of the International Ski Federation, or FIS (Federation Internationale de Ski). In 1992, the FIS recognized roller skiing as a sport distinct from cross-country skiing. The first World Games were held in The Hague in 1993, and the first World Cup roller ski races later in the same year.