The 200Â metres, or 200-meter dash, is a sprint running event. On an outdoor 400-metre racetrack, the race begins on the curve and ends on the home straight, so a combination of techniques is needed to successfully run the race. A slightly shorter race, called the stadion and run on a straight track, was the first recorded event at the ancient Olympic Games. The 200Â m places more emphasis on speed endurance than shorter sprint distances as athletes predominantly rely on anaerobic energy system during the 200 m sprint. Similarly to other sprint distances, the 200 m begins from the starting blocks. When the sprinters adopt the 'set' position in the blocks they are able to adopt a more efficient starting posture and isometrically preload their muscles. This enables them to stride forwards more powerfully when the race begins and start faster.
In the United States and elsewhere, athletes previously ran the 220-yard dash (201.168Â m) instead of the 200Â m (218.723 yards), though the distance is now obsolete. The standard adjustment used for the conversion from times recorded over 220 yards to 200Â m times is to subtract 0.1 seconds, but other conversion methods exist. Another obsolete version of this race is the 200 metres straight, which was run on tracks that contained such a straight. Initially, when the International Amateur Athletic Association (now known as the International Association of Athletics Federations) started to ratify world records in 1912, only records set on a straight track were eligible for consideration. In 1951, the IAAF started to recognise records set on a curved track. In 1976, the straight record was discarded.