Triathlon races vary in distance. According to the International Triathlon Union, and USA Triathlon, the main international race distances are Sprint distance (750 m swim, 20 km bike, 5 km run), Intermediate (or Standard) distance, commonly referred to as "Olympic distance" (1.5 km swim, 40 km ride, 10 km run), the Long Course (1.9 km swim, 90 km ride, 21.1 km run, such as the Half Ironman), and Ultra Distance (3.8 km swim, 180 km ride, and a marathon: 42.2 km run); the most recognized branded Ultra Distance is the Ironman triathlon.
Transition areas are positioned both between the swim and bike segments (T1), and between the bike and run segments (T2) and are where the switches from swimming to cycling and cycling to running occur. These areas are used to store bicycles, performance apparel, and any other accessories needed for preparing and for the next stage of the race. The time spent in T1 and T2 are included in the overall time of the race. Transitions areas can vary in size depending on the number of participants expected for the race. In addition, these areas provide a social headquarters prior to the race.
The nature of the sport focuses primarily on persistent and often periodized training in each of the three disciplines, as well as combination workouts and general strength conditioning.
