Olympic sports
Olympic sports are contested in the Summer Olympic Games and Winter Olympic Games. The 2016 Summer Olympics included 28 sports, with five additional sports due to be added to the 2020 Summer Olympics program; the 2014 Winter Olympics included seven sports. The number and types 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, each Olympic sport can be subdivided into multiple disciplines, which are often mistaken as distinct sports. Examples include swimming and water polo, which are in fact disciplines of the sport of aquatics (represented by the International Swimming Federation), and figure skating and speed skating, which are both disciplines of the sport of ice skating (represented by the International Skating Union). In turn, disciplines are subdivided into events, for which Olympic medals are awarded. A sport or discipline is included in the Olympic program if the IOC determines it to be widely practised around the world, that is, the popularity of a given sport or discipline is indicated by the number of countries that compete in it. The IOC's requirements also reflect participation in the Olympic Games – more stringent conditions are applied to men's sports/disciplines (as men are represented at the Games in higher numbers than women) and to summer sports/disciplines (as more nations compete in the Summer Olympics than in the Winter Olympics).
Underwater sports
As of 2013, there has been no competition at an Olympic Games by any underwater sport, even as a demonstration, although the following breath-hold events have been conducted as part of the swimming competition - underwater swimming event at the 1900 Summer Olympics in Paris and a plunge for distance event at the 1904 Summer Olympics in St. Louis, Missouri. During the 1950s and the 1960s, various parties including the Amateur Athletic Union of the United States and the International Underwater Spearfishing Association lobbied for the admission of spearfishing to the Olympics. It is reported that in 1968, the International Olympic Committee (IOC) voted in favour of synchronized swimming over spearfishing. In 1999, finswimming was reported as being considered for inclusion in the 2004 Summer Olympics in Athens, Greece. In 2002, Underwater sports was one of the sports considered by the IOC for addition to the programme of the 2008 Summer Olympics in Beijing, China. It and eight other sports were declined admission on the basis of: Statistics reviewed on federation affiliation, nations competing in major events and broadcast and press coverage of major events for most requested sports did not indicate a higher level of global participation and interest than sports currently in the Programme, and
therefore could not be considered to bring additional value.