The number and kinds of events may change slightly from one Olympiad to another. Each Olympic sport is represented by an international governing body, namely an International Federation (IF).
The International Olympic Committee (IOC) establishes a hierarchy of sports, disciplines, and events. According to this hierarchy, the Olympic sports can be subdivided into multiple disciplines, which are often assumed to be distinct sports. Examples include swimming and water polo (disciplines of Aquatics, represented by the International Swimming Federation), or figure skating and speed skating (disciplines of Skating, represented by the International Skating Union).In their turn, disciplines can be subdivided into events, for which medals are actually awarded.A sport or discipline is included in the Olympic program if the IOC determines it is widely practiced around the world, that is, the number of countries that compete in a given sport is the indicator of the sport's prevalence.
