A triathlon is a sports event which combines three sports, typically running, biking, and swimming. During a triathlon, competitors perform all three sports sequentially without stopping, in an attempt to beat the clock. People of all ages and sizes compete in triathlons, although a circuit of professional athletes dominates the triathlon world, much like with other sports events. Training for a triathlon, as well as competing, can be a great way to get in shape and enjoy sports. In addition, many triathlons are held to benefit charity, much like marathons, which encourages athletes at varying levels of experience and physical ability to compete.
The modern triathlon emerged in California in the 1970s, and typically begins with the swimming leg, followed by cycling, and finally running. A triathlon tests the endurance and speed of an athlete, as well as his or her ability to conserve energy and focus on the race as a whole. Triathletes are usually extremely strong and limber, with powerful upper bodies for swimming and well developed lower bodies for biking and running.
Because a triathlon involves competing against a clock, rather than against other athletes, it is an individualized but not brutally competitive sport. Usually groups of athletes are sent out in stages, to avoid clogging up the field, typically beginning with professionals and following with amateurs broken up by age group. A variation on the triathlon is a relay triathlon, in which a different athlete completes each stage.
The swimming stage typically takes place in a lake or the open ocean. As soon as athletes emerge from the water, they immediately change into cycling gear, as the transition time between stages is counted in the overall time. After cycling, the athletes change shoes to run, and the course is considered complete once the athletes have crossed the finish line. In longer triathlons, help stations along the way offer water, food, electrolytes, and other supplies to athletes, along with first aid for injuries.
The length of a triathlon can vary immensely. In a super sprint triathlon, athletes compete over very short distances, typically a quarter mile (400 meter) swim, a six mile (10 kilometer) bike ride, and a one and a half mile (two and a half kilometer) run. By contrast, the Ironman Triathlon, held annually in Hawaii, features a 2.4 mile (3.8 kilometer) swim, a 110 mile (180 kilometer) bike ride, and a 26.2 mile (42.2 kilometer) bike ride. An even more grueling event, the Ultraman Triathlon, takes place over three days, and covers 320 miles (515 kilometers).