A triathlon is an event that combines swimming, cycling, and running. It is a multi-sport event that requires athletes to complete all three disciplines in succession. The event usually consists of a swim leg, followed by a bike leg, and then a run leg. The distances for each leg vary depending on the type of triathlon, but typically involve swimming between 0.5 and 2.4 miles, cycling between 12 and 112 miles, and running between 3.1 and 26.2 miles.