The 10-second barrier is a term used in track and field athletics which refers to the physical and psychological barrier of completing the men's 100 metres sprint in under ten seconds. The achievement was traditionally regarded as the hallmark of a great sprinter, but its significance has become less important since the late 1990s as an increasing number of runners have surpassed the ten seconds mark.

The first sub-10 second finishes were recorded through the use of manual timing by stopwatch. However, the International Association of Athletics Federations now states that runs are only legal if achieved with the use of fully automatic timing, a wind speed below 2.0 m/s, and without the use of performance enhancing substances. Wind gauge malfunctions or infractions may also cause sprinters' runs to be invalid.

Under these rules, the barrier was first officially broken by American athlete Jim Hines on 14 October 1968. He ran a time of 9.95 seconds to win the 100 metres at the 1968 Olympics, setting a new world record. Almost nine years passed before the barrier was broken again; Silvio Leonard ran 9.98 seconds on 11 August 1977. Both of these marks were recorded at a high altitude, which aids performance due to lower air resistance. Carl Lewis was the first sprinter to achieve the feat at a low altitude, with 9.97 seconds on 14 May 1983 at the Modesto Relays. Calvin Smith recorded a world record 9.93 seconds on 3 July 1983, and also became the first sprinter to run under ten seconds twice, repeating the feat in August that year.

Christophe Lemaitre (French pronunciation: [kʁistɔf ləmɛtʁ]; born 11 June 1990 in Annecy, France) is a French sprinter, who specialises in the 100 and 200 metres. He is the French 100 m and 200 m record holder with a time of 9.92 seconds and 19.80 seconds as well as being the first caucasian to break the 10-second barrier in an officially timed event.

At the age of 20, he won the 100 m, 200 m and the 4×100 m relay titles at the 2010 European Championships, the first sprinter ever to do this treble, making him the fastest man in Europe.

Lemaitre grew up in the town of Culoz, where he practiced handball, rugby and football, before his speed was discovered. In 2005 at the age of 15, during national sprinting events, Lemaitre ended up with the fastest 50 metres in the country. A month after his 16th birthday in 2006, and less than a year after joining an athletics club at Aix-les-Bains, Lemaitre ran 100m in 10.96 seconds. His personal best improved to 10.53 seconds in 2007.

In 2008, he ran a new 100m personal best of 10.26 seconds. At the 2008 World Junior Championships in Athletics, Lemaitre won the 200 m title with a time of 20.83 seconds.

James "Jim" Ray Hines (born September 10, 1946) is a former American track and field athlete, who held the 100 m world record for 15 years. He was the first sprinter to officially break the 10-second barrier in the 100 meters, running an electronically timed 9.95 to win the 1968 Olympics at altitude in Mexico City.

Born in Dumas, Arkansas, Hines was raised in Oakland, California and graduated from McClymonds High School in 1964. He was a baseball player in his younger years, until he was spotted by a track coach as a running talent and became a sprinter. At the 1968 US national championships in Sacramento, California, Hines became the first man to break the ten second barrier in the 100 meter race, setting 9.9 (manual timing), with a real time of 10.03 - two other athletes, Ronnie Ray Smith behind him (real time 10.13) and Charles Greene on the other semi-final (real time 10.09) having got the same official clocking. That evening of June 20, 1968 at Hughes Stadium has been dubbed by track and field historians as the "Night of Speed." Hines attended Texas Southern University in Houston, Texas. He was a member of the Texas Southern University Tigers track team.

James Dasaolu (born 5 September 1987) is a British sprint athlete who specialises in the 100 metres.

He began his career in competitive athletics relatively late, first competing in 2006. However, Croydon Harrier Dasaolu made steady and significant improvements in his first few years; his 100 m personal best in 2006 was 10.75 seconds, then 10.33 seconds in 2007, and 10.26 seconds in 2008.

The 2008 season saw Dasaolu rise up the national rankings and introduced to the UK Athletics warm weather training camp. Under the tutelage of coach Michael Khmel at Loughborough University and training with 2006 World Junior Champion Harry Aikines Aryeetey and former European Junior Champion Leon Baptiste, Dasaolu won the 2008 England under-23 championships and reached the semi-finals at the British Olympic Trials.

The beginning of the 2009 season showed further improvement for Dasaolu. At the seventh Graziano Della Valle meet in Italy, he recorded a new personal best of 10.15 seconds and finished in second place overall behind Aikines Aryeetey. Two weeks later he finished with 10.25 seconds at the Papaflessia meet in Greece, second only to European season leader Dwain Chambers. A 100 m win at the European Athletics permit meet in Geneva in June placed him among the top European sprinters for the first time. His new personal best time of 10.09 seconds made him joint second, with Simeon Williamson, in the season's 100 m European rankings and improved his chances for a place on the British relay team at the Berlin World Championships.

The Honourable Usain St. Leo Bolt, OJ, C.D. ( /ˈjuːseɪn/; born 21 August 1986), is a Jamaican sprinter and a five-time World and three-time Olympic gold medalist. He is the world record and Olympic record holder in the 100 metres, the 200 metres and (along with his teammates) the 4×100 metres relay. He is the reigning Olympic champion in these three events, and is one of only seven athletes (along with Valerie Adams, Veronica Campbell-Brown, Jacques Freitag, Yelena Isinbayeva, Jana Pittman, Dani Samuels) to win world championships at the youth, junior, and senior level of an athletic event.

Bolt won a 200 m gold medal at the 2002 World Junior Championships, making him the competition's youngest-ever gold medalist at the time (since surpassed by Jacko Gill). In 2004, at the CARIFTA Games, he became the first junior sprinter to run the 200 m in less than 20 seconds with a time of 19.93 s, breaking the previous world junior record held by Roy Martin by two-tenths of a second. He turned professional in 2004, and although he competed at the 2004 Summer Olympics, he missed most of the next two seasons due to injuries. In 2007, he broke Don Quarrie's 200 m Jamaican record with a run of 19.75 s.