100 metres

100 m (one hundred metres) is the shortest outdoor sprint race distance in athletics. The reigning 100 m Olympic champion is often named "the fastest man/woman in the world". A distance of 100 yards (91 m) was often run in the past, but this is now obsolete. Indoors events are normally held over 60 m (sometimes 50 m or 55 m) as few facilities have a 100 m indoor straight.

On an outdoor 400 m running track, the 100 m is run on the home straight, the start being set on an extension to make it a straight line race. Illegal drug use has been seen by some people as a means to gain a competitive edge; in particular, the scandal at the 1988 Summer Olympics when the winner Ben Johnson was stripped of his medal.

Record performances

Major 100 m races, such as at the Olympic Games, attract much attention, particularly when the world record is thought to be within reach. The men's world record has been improved upon eleven times since the introduction of electronic timing in 1968, never being surpassed by more than 0.05 s at a time. The current men's world record of 9.74 seconds is held by Asafa Powell of Jamaica, set in Rieti, Italy on September 9, 2007. In the women's competition the world record belongs to Florence Griffith-Joyner who ran a time of 10.49 seconds in Indianapolis on 16 July, 1988. Due to the progression of record times compared to longer distances, the downward march of the 100-meter record has been criticized as more a measure of technological advances than athletic greatness.^[1]

Start

At the start, some athletes play psychological games such as trying to be last to the starting blocks, although direct intimidation would be considered unsporting. The starter will keep the sprinters in the set position for an unpredictable time of around two seconds and then fire the starting gun.

The time between the gun and first kick against the starting block is measured electronically, via sensors built in the gun and the blocks. A reaction time less than 0.1 seconds is considered a false start. The 0.1 second interval accounts for the sum of the time it takes for the sound of the starter's pistol to reach the runners' ears, and the time it takes for a human to react to it.

For many years a sprinter was disqualified if they were responsible for two false starts individually. However, this rule was allowing some major races to be restarted so many times that the sprinters started to lose focus. The new rule is that, after one false start, anyone responsible for a subsequent false start is disqualified immediately, though this rule has led to some sprinters deliberately false-starting to gain a psychological advantage, especially by the slower starters in the field.

Climatic conditions

Climatic conditions are a crucial factor for good performances in the 100 m. Air resistance is the primary climatic factor in sprint performances. A strong head wind is very detrimental to performance, while a tail wind can improve performances significantly. For this reason, a maximum tail wind of 2.0 m/s is allowed for a 100 m performance to be considered eligible for records, or 'wind legal'. Furthermore, sprint athletes perform better at high altitudes because of the thinner air, which provides less air resistance. While there are no limitations on altitude, performances made at altitudes greater than 1000 m above sea level are marked with an "A".^[2]

For example, on April 13 1996 Obadele Thompson of Barbados ran the fastest 100 m race ever in El Paso,Texas. He was clocked at 9.69 s. However, it was achieved with a tail wind in excess of 5 m/s, well over the IAAF legal limit of 2.0 m/s, and the mark was not officially recognized.

Fastest 100 metres runners

Top twelve all-time athletes — men

Updated 18 September, 2007

Rank	Time	Wind (m/s)	Athlete	Nation	Date	Location
1	9.74	+1.7	Asafa Powell^[1]	Jamaica	9 September 2007	Rieti
2	9.77	+1.7	Justin Gatlin^[2]	United States	12 May 2006	Doha
3	9.79	+0.1	Maurice Greene	United States	16 June 1999	Athens
4	9.84	+0.7	Donovan Bailey^[3]	Canada	27 July 1996	Atlanta
		+0.2	Bruny Surin	Canada	22 August 1999	Seville
		+1.0	Tyson Gay	United States	18 August 2006	Zürich
		−0.5	Tyson Gay	United States	24 June 2007	Indianapolis
7	9.85	+1.2	Leroy Burrell	United States	6 July 1994	Lausanne
7	9.85	+1.7	Olusoji Fasuba	Nigeria	12 May 2006	Doha
9	9.86	+1.2	Carl Lewis	United States	25 August 1991	Tokyo
		−0.4	Frank Fredericks	Namibia	3 July 1996	Lausanne
		+1.8	Ato Boldon	Trinidad and Tobago	19 April 1998	Walnut
		+0.6	Francis Obikwelu	Portugal	22 August 2004	Athens

Notes

Powell has also run 9.77 seconds three times and has once run 9.78 seconds.
Although Justin Gatlin's time has been ratified, it is pending disqualification by the IAAF for doping charges brought against him. He is currently serving an eight year ban. The decision whether to disqualify his result will be made in 2007.
Donovan Bailey's time is currently the Olympic record.

Ben Johnson's times (9.79 at Seoul on 24 September 1988 and 9.83 at Rome on 30 August 1987) were subsequently invalidated. His 9.79 was not ratified due to the presence of steroids in his urine sample after the race. His previously ratified 9.83 was invalidated in 1989 after his admission of extended drug use. From 1 January 1990, Carl Lewis' 9.92 was recognized as the world record. Though not recognized as records at the time, his runs of 9.93 were subsequently seen as having tied the previous record.
Tim Montgomery's time (9.78 at Paris on 14 September 2002) was invalidated following indictment in the BALCO scandal on drug use and drug trafficking charges. The time had stood as the world record until Asafa Powell first ran 9.77.

Top ten all-time athletes — women

Updated by July 27, 2005

Rank	Time	Wind (m/s)	Athlete	Nation	Date	Location
1	10.49	0.0	Florence Griffith Joyner	United States	16 July 1988	Indianapolis
2	10.73	+2.0	Christine Arron	France	19 August 1998	Budapest
3	10.74	+1.3	Merlene Ottey	Jamaica	7 September 1996	Milan
4	10.76	+1.7	Evelyn Ashford	United States	22 August 1984	Zürich
5	10.77	+0.9	Irina Privalova	Russia	6 July 1994	Lausanne
5	10.77	+0.7	Ivet Lalova	Bulgaria	19 June 2004	Plovdiv
7	10.78A	+1.0	Dawn Sowell	United States	3 June 1989	Provo
8	10.79	0.0	Li Xuemei	China	18 October 1997	Shanghai
8	10.79	−0.1	Inger Miller	United States	22 August 1999	Seville