Duathlon is an athletic event that consists of a running leg, followed by a cycling leg and then another running leg in a format bearing some resemblance to triathlons. The International Triathlon Union governs the sport internationally.
Duathlons are conducted at sprint, standard and long distances. Sprint distance duathlons are a 5 kilometers run, a 20 kilometers bike, and a 2.5 kilometers run. Standard distance duathlons are a 10 kilometers run, a 40 kilometers bike, and a 5 kilometers run. Long distance duathlons have not been standardized but the Powerman Zofingen course is a 10 kilometer run, a 150 kilometer bike and a 30 kilometer run.
Duathlons are most similar to triathlons, with the key difference being the lack of a swimming leg. Other sports derived from triathlon include aquathlon, which combines swimming and running but has omitted the cycling part, and aquabike, with the swim and bike but no run.
In this variation, the cycling and running segments need to be undertaken simultaneously by a team consisting of a predetermined number of individuals. Only one of the team members is running while all others are cycling. All the members of a team must be together at any given point of time but exchanging the tasks of running and cycling amongst the team members themselves is permitted.
The challenge is to rotate the task of running at an optimum rate such that the time from start to destination is minimized. This demands a smooth coordination amongst all team members which makes the sport more exciting. An example is the 100 km-Duathlon around Dresden which is the oldest of its kind in Germany.
The world's largest duathlon to date is the inaugural London Duathlon, which took place on 17 September 2005 in Richmond Park, Surrey. Approximately 2,500 people took part. The main race consisted of a 10 km run, 20 km cycle ride and 5 km run. Since 2005 London Duathlon has grown to just under 4,000 participants, 2010 saw the first running of the Ultra Distance at London which will consist of 20 km run, 77 km bike and 10 km run. Now in its 9th year, London Duathlon will be taking place on Sunday 14 September 2014 offering athletes of all abilities the chance to race through the stunning surroundings of Richmond Park while on closed roads. "Classic" distance consists of a 10 km run, 44 km cycle ride and 5 km run.