100 metres
Updated: Wikipedia source
The 100 metres, or 100-meter dash, is a sprint race in track and field competitions. The shortest common outdoor running distance, the 100-metre (109.36 yd) dash is one of the most popular and prestigious events in the sport of athletics. It has been contested at the Summer Olympics since 1896 for men and since 1928 for women. The inaugural World Championships were in 1983. On an outdoor 400-metre running track, the 100 m is held on the home straight, with the start usually being set on an extension to make it a straight-line race. There are three instructions given to the runners immediately before and at the beginning of the race: "on your marks", "set", and the firing of the starter's pistol. The runners move to the starting blocks when they hear the "on your marks" instruction. The following instruction, to adopt the "set" position, allows them to adopt a more efficient starting posture and isometrically preload their muscles: this will help them to start faster. A race-official then fires the starter's pistol to signal the race beginning and the sprinters stride forwards from the blocks. Sprinters typically reach top speed after somewhere between 50 and 60 m. Their speed then slows towards the finish line.
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 men's world record is 9.58 seconds, set by Jamaica's Usain Bolt in 2009, while the women's world record is 10.49 seconds, set by American Florence Griffith-Joyner in 1988. The 100 metres is considered one of the blue ribbon events of the Olympics and is among the highest profile competitions at the games. It is the most prestigious 100 metres race at an elite level and is the shortest sprinting competition at the Olympics – a position it has held at every edition except for a brief period between 1900 and 1904, when a men's 60 metres was contested. The unofficial "world's fastest man or woman" title typically goes to the Olympic or world 100 metres champion. The 200 metre time almost always yields a "faster" average speed than a 100-metre race time, since the initial slow speed at the start is spread out over the longer distance. The current men's Olympic champion is Noah Lyles, while the current world champion is Oblique Seville. The current women's Olympic champion is Julien Alfred, and the world champion is Melissa Jefferson-Wooden.