How it works
Runners race for 100m around a bend and 100m down the home straight. They start from blocks and run in lanes.
A reaction time – measured by sensors in the starting pistol and on the blocks – of less than 0.1 is deemed a false start and runners will be recalled, and the responsible athlete disqualified. A runner can also be disqualified if he or she steps out of their designated lane.
A slightly shorter race than the current 200m (192m, one length of the stadium) was part of the Ancient Olympics. The 200m (for men) was added to the Olympic programme in 1900 and has been part of all subsequent Games, except 1906.
Women have contested the distance in every Olympics since 1948.
Did you know
The second half of a 200m race is often quicker than the first half, as athletes approach the final 100m at full speed. When Usain Bolt set his 19.19 world record, he covered the final 100m in 9.27 seconds.
American men have won 17 Olympic titles, one more than their tally of 100m gold medals. There has been at least one Jamaican medallist in each of the past nine women’s Olympic finals.