<P> The reigning 100 m Olympic champion is often named "the fastest man in the world". The World Championships 100 metres has been contested since 1983 . Americans Justin Gatlin and Tori Bowie are the reigning world champions; Usain Bolt and Elaine Thompson are the Olympic champions in the men's and women's 100 metres, respectively . </P> <P> On an outdoor 400 metres running track, the 100 m is run on the home straight, with the start usually being set on an extension to make it a straight - line race . Runners begin in the starting blocks and the race begins when an official fires the starter's pistol . Sprinters typically reach top speed after somewhere between 50--60 m . Their speed then slows towards the finish line . </P> <P> The 10 - second barrier has historically been a barometer of fast men's performances, while the best female sprinters take eleven seconds or less to complete the race . The current men's world record is 9.58 seconds, set by Jamaica's Usain Bolt in 2009, while the women's world record of 10.49 seconds set by American Florence Griffith - Joyner in 1988 remains unbroken . </P> <P> The 100 m (109.361 yards) emerged from the metrication of the 100 yards (91.44 m), a now defunct distance originally contested in English - speaking countries . The event is largely held outdoors as few indoor facilities have a 100 m straight . </P>

Who hold the world record in 100m sprint