Speed skating is a competitive form of ice skating in which the competitors race each other in travelling a certain distance on skates. Types of speed skating are long track speed skating, short track speed skating, and marathon speed skating. In the Olympic Games, long-track speed skating is usually referred to as just "speed skating", while short-track speed skating is known as "short track". The International Skating Union (ISU), the governing body of competitive ice sports, refers to long track as "speed skating" and short track as "short track skating". An international federation was founded in 1892, the first for any winter sport. The sport enjoys large popularity in the Netherlands, Norway and South Korea. There are top international rinks in a number of other countries, including Canada, the United States, Germany, Italy, Japan, Russia, Kazakhstan, China, Belarus and Poland. A World Cup circuit is held with events in those countries plus two events in the Thialf ice hall in Heerenveen, Netherlands. Overview The standard rink for long track is 400 meters long, but tracks of 200, 250 and 333 meters are used occasionally. It is one of two Olympic forms of the sport and the one with the longer history. ISU rules allow some leeway in the size and radius of curves. Short track speed skating takes place on a smaller rink, normally the size of an ice hockey rink, on a 111.12 m oval track. Distances are shorter than in long-track racing, with the longest Olympic individual race being 1500 meters (the women's relay is 3000 meters and the men's relay 5000 meters). Event are usually held with a knockout format, with the best two in heats of four or five qualifying for the final race, where medals are awarded. Disqualifications and falls are not uncommon. There are variations on the mass-start races. In the regulations of roller sports, eight different types of mass starts are described. Among them are elimination races, where one or more competitors are eliminated at fixed points during the course; simple distance races, which may include preliminary races; endurance races with time limits instead of a fixed distance; points races; and individual pursuits. Races usually have some rules about disqualification if an opponent is unfairly hindered; these rules vary between the disciplines. In long track speed skating, almost any infringement on the pairmate is punished, though skaters are permitted to change from the