Olympic distance of 1.5/40/10km (0.93/24.8/6.2miles) was created by longtime triathlon race director Jim Curl in the mid-1980s, after he and partner Carl Thomas produced the U.S. Triathlon Series (USTS) between 1982 and 1997. Sprint triathlons are the most common triathlon distance in the United States. In 2022, for example, there were 839 USAT sanctioned sprint triathlons, more than all other distances combined. In addition to the above distances, two new long-distance events have appeared, the 111 and 222 events. The 111 distance is swimming, bicycling and running, totalling . The 222 distance is double that. Most triathlons are individual events. Another format is relay triathlons, where a team of competitors take turns to compete at a race; each competitor must do a segment of swimming, cycling and running. The World Triathlon Mixed Relay Championships began with two separate classifications for men and women. In 2009, it adopted a 4x4 mixed relay format, where each team has two men and two women. The triathlon at the Youth Olympic Games also has a 4x mixed relay since 2010, and the event was introduced at the 2020 Summer Olympics. The World Triathlon accepts a 5% margin of error in the cycle and run course distances. Though there can be some variation in race distances, particularly among short triathlons, most triathlons conform to one of those above standards. Race organization In general, participation in a triathlon requires an athlete to register and sign up in advance of the actual race. After registration, racers are often provided a race number, colored swim cap, and, if the event is being electronically timed, a timing band. Athletes will either be provided or briefed on details of the course, rules, and any problems to look out for (road conditions, closures, traffic lights, aid stations). At a major event, such as an Ironman or a long course championship, triathletes may be required to set up and check-in their bike in the transition area a day or two before the race start, leaving it overnight and under guard. On the day of the race, before the start of competition, athletes will generally be provided with a bike rack to hold their bicycle and a small section of ground space for shoes, clothing, etc. in the transition area. In some triathlons, there are two transition areas, one for the swim/bike change, then one for the bike/run change at a different location.