A test of both endurance and athletic versatility, the Olympic triathlon requires competitors to excel at three very different and demanding disciplines: swimming, cycling and running. Olympic triathletes swim 1500m, bike 40km and run 10,000m. Men and women compete seperately.
In London, triathlon will take place in Hyde Park, where 3,000 spectators will enjoy a grandstand view of the finishing area, with many thousands more able to watch as the athletes swim, cycle and run on the course.
The first leg in the Olympic triathlon competition consists of a 1,500m open-water swim.
In the swim leg of the Olympic triathlon, competitors may use any stroke to propel themselves through the water. During the swim, competitors may stand on the bottom or rest by holding an inanimate object such as a buoy or stationary boat but may not use either to gain an advantage. In an emergency, a competitor can call for assistance by raising an arm overhead. Once assistance is given, the competitor must retire from the race. Triathletes are allowed to wear wetsuits during the swim leg only if the water temperature is 20 degrees Celsius (68 degrees Fahrenheit) or lower. Wetsuits are mandatory in water colder than 14 degrees Celsius (57.2 degrees Fahrenheit).
As the first leg of the triathlon competition, the swim sets the stage for the entire race and can often make or break a competitor's shot at a medal. How an athlete approaches the swim leg depends on the competitor's individual strengths and weaknesses. If the swim is a triathlete's strongest event, it is important that he or she pull ahead of the pack and leave the water as far ahead of the other competitors as possible. Building up a lead going into the bike leg gives the swimmer a buffer zone that the other competitors, who may be stronger cyclists, must overcome. Positioning is key for the athletes whose strongest event is not the swim. This triathlete needs to stay close to the lead pack and not fall so far behind as to make catching up on dry land impossible. Weaker swimmers often hang back and draft off the lead swimmers, allowing them to conserve energy for the next leg, the bike.
After the opening swim, the second leg of an Olympic triathlon requires competitors to ride a bike over a road course that is 40 kilometers (24.9 miles) in length.
In the bike leg of the Olympic triathlon, competitors are allowed to draft off of one another. Drafting occurs when a competitor rides directly behind another competitor -- the rider in back feels less wind resistance and can thus maintain the same speed as the rider in front without using as much energy. Although drafting is allowed, competitors are not allowed to block out other riders. No forward progress is allowed without the bicycle. Competitors who appear to present a danger to themselves or others may be disqualified and removed from the competition by the race officials. Competitors may not ride the bike in the transition area. If a rider does not honor the mount line (where they must begin riding the bike) and the dismount line (where they must get off the bike), he or she is subject to a time penalty or disqualification.
As in the swim leg, a competitor's strengths and weaknesses determine how he or she will attack the bike course. The strong bikers will often break away from the pack in order to build up a lead over the other athletes who might excel at the run, while the stronger runners will stay in the pack and draft off the lead riders (a legal tactic in Olympic triathlon competition). In an Olympic triathlon, every second counts, so an efficient transition from swim to bike is crucial. A clean swim-to-bike transition typically takes between 20 and 30 seconds.
The final leg in the Olympic triathlon competition consists of a 10,000m run over a road course. This distance corresponds to the longest Olympic running event contested on the track.
In the run leg of the Olympic triathlon, competitors are allowed to walk but not allowed to crawl. Headphones and headsets are not permitted during competition. A competitor finishes the race when any part of the torso, excluding the head, neck, shoulders, arms, hips or legs, reaches the perpendicular line extending from the leading edge of the finish line.
All the strategy and positioning of the first two legs bring the triathletes to the final segment of the competition. In the run, the primary tactic for triathletes is simply to cover the 10,000 meters as fast as they can. The athlete whose strongest event was either the swim or the bike hopes to have built up enough of a lead that he or she can hold off strong runners challenging from behind. The racer whose best event is the run hopes that, over the course of the first two legs, he or she has been able to stay within striking distance of the leaders and has enough reserved energy to make a final push at the end. The transition from bike to run is hugely important, and tends to be a bit quicker than the swim-to-bike exchange. Competitors must discard their cycling gear and put on their running shoes as efficiently as possible.