One of the simplest and most accessible forms of multisport, aquathlon consists of three legs, with a swim sandwiched between two run segments. The official distances for the annual ITU Aquathlon World Championships are a 2.5km run, 1km swim, and 2.5km run. This can change if the water temperature is lower than 22 degrees, in which case the race becomes a 1km swim followed by a 5km run.