A Triathlon is an athletic event that includes swimming, running, and cycling. A triathlon requires the Triathlete to swim ½ mile, bike 12.4 miles and run 3.1 miles. Triathletes can move from a sprint event to an Olympic event, half-Ironman, through a long distance one, and on to the Ironman (also known as the ultra). To compete in this event, triathletes must swim 2.4 miles, bike 112 miles and then run a marathon (26.2 miles).