Triathlon is a multi-stage competition which normally include swimming, cycling, and running. The winner is determined by fast overall course completion time. During competitions, a transition area allows triathletes to change gear for different segments of the race. Thus, they are seen switching from swimming to cycling then cycling to running.

History of triathlon can be traced back to France in 1920s. The sport is said to be based on race called “Les trois sports”, “La Course des Débrouillards”, and “La course des Touche à Tout.”

The earliest tri-sport event was possibly an event in 1902. This race included running, cycling, canoeing. Afterward, other related events were documented from the 1920s until 190s.

The first event to be called “triathlon” took place at Mission Bay, San Diego, California on September 25, 1974. This even was headed by Jack Johnstone and Don Shanaham.

In 1989, the International Triathlon Union (ITU) was established. The organization was put up with aim of including triathlon on the Olympic program. ITU is also in charge in organizing the World Cup and World Triathlon Series and implements the necessary sanctions. In these events, recognition is given to elite pro-triathletes, junior pro-triathletes, and age-group athletes.

On the other hand, the World Triathlon Corporation (WTC) is a private organization which is in charge of Ironman and Ironman 70.3 races every year. People join the Ironman race to qualify for annual World Championships, which is held annually in Kailua-Kona, Hawaii. Meanwhile, Ironman 70.3 is held in a different location each year.

International Ultra-Triathlon Association (IUTA) is in charge of Ultratriathlon, an event that covers longer distances compared with the usual iron-distance races.

Triathlon made it to the Olympic program at the Sydney Games in 2000, whereas Paratriathlon debuted at the 2016 Summer Paralympics in Rio de Janeiro, Brazil.

Ultra-triathlons included triathlons that cover longer distances. However, distances may vary depending on the choice of race organizers and their goal to meet various distance constraints.

The standard Olympic distance is 1.5/40/10 km, which was created by the triathlon race director, Jim Curl. Meanwhile, newer distances include the 111 and 222 events. In 111 distance, triathletes must cover 1 km while swimming, 100 km bicycling, and 10 km running. The 222 distance involves twice the distances covered in 111 event.

Triathletes join triathlon events for improvement and maintenance of their physical fitness. Each event in triathlon provides remarkable cardiovascular events. Participation in such events require intense training that should be able to improve endurance sports performance. In relation to this, triathletes are also known for participating in other activities, including yoga, pilates, and weight training.

In swimming, triathletes are more careful when using their legs. They use different swim strokes to compensate for turbulent, aerated water and to conserved their energy. Triathletes also employ different techniques to take advantages of water movements and waves of the sea.

Meanwhile, cycling may allow drafting or formation of pelotons. In organizing the cycling event of triathlon, running performance of participants is considered. Triathletes also normally use triathlon bicycles, which are customized with special handlebars, called aero-bars or tri-bars, aerodynamic wheels, and other accessories to improve aerodynamics. Even the seat is customized not only to improve aerodynamics but to preserve some muscles that are used for running.

During running, most muscles of participants are already tired from performing two equally exhausting physical activities. Beginners may suffer from weakness and muscle pain caused by lactate accumulation. Thus, intense training is required before any qualified athlete can join a triathlon event.