Often called 'ironman' or '140.6', with the 140.6 referring to the total distance covered in miles - a 2.4-mile swim (3.9km), a 112-mile bike ride (180km), and a marathon 26.2-mile run (42.2km) to finish. It is widely acknowledged to be one of the toughest one-day sporting challenges.
The original idea came from Navy Commander John Collins who founded the first race on the island of Honolulu in 1978. The format remains the same to this day, with around 30 officially sanctioned IRONMAN races which are organised by the World Triathlon Corporation (WTC). They culminate in a World Championship which since 1982 has been held at Kona in Hawaii.
UK locations include Bolton, Tenby and Weymouth, but there are many other long distance triathlons over exactly the same distance, just without the IRONMAN branding. So if you think you're a potential ironman then read on...
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