The 400 metres, or 400 metre dash, is a common sprinting event in track and field competitions. It has been featured in the athletics programme at the Summer Olympics since 1896 (1964 for women). On a standard outdoor running track, it is exactly one lap around the track. Runners start in staggered positions and race in separate lanes for the entire course. In many countries, athletes previously competed in the 440 yard dash (402.336 m)—also referred to as the 'quarter-mile'—instead of the 400 m, though this distance is now obsolete. An athlete who competes in the 400 m may still be referred to as 'quarter-miler'.

Maximum sprint speed capability is a significant contributing factor to success in the event, but athletes also require substantial speed-endurance and the ability to cope well with high amounts of lactic acid to sustain a fast speed over a whole lap. Whilst considered to be predominantly an anaerobic event, there is some aerobic involvement and the degree of aerobic training required for 400 metre athletes is open to debate.^{[citation needed]}

LaShawn Merritt (born June 27, 1986) is an American track and field athlete who competes in sprinting events, specializing in the 400 meters. He is the reigning Olympic champion over the distance and his personal best of 43.75 seconds makes him the fifth fastest of all time. In October 2010 he was suspended for 21 months for failing a doping test.

He was a successful junior athlete and won the 400 m gold at the 2004 World Junior Championships in Athletics, as well as setting two world junior records in the relays. He became part of the American 4×400 meter relay team and helped win the event at the 2006 IAAF World Indoor Championships. He established himself individually in 2007 by winning a silver medal in the 400 m at the 2007 World Championships.

He came out on top of a rivalry with Jeremy Wariner in 2008 by winning in the 2008 Olympic final in a personal best time, and by a record margin. He also broke the Olympic record in the relay with the American team, recording the second fastest time ever. Merritt established himself as the World Champion with a win at the 2009 World Championships in Athletics in the 400 m and the 4×400 m relay. He failed three drugs tests in the winter of 2009–2010, testing positive for the banned steroid Dehydroepiandrosterone, which he had allegedly consumed through the use of a penis enlargement drug. He accepted a two year ban from the sport.

Jerry Miculek is a speed shooter and competition shooting instructor. He is renowned as one of the fastest revolver shooters in the world, emptying a five-shot revolver in 0.57 seconds in a group the size of a playing card.^{[citation needed]} Miculek currently holds five world records in exhibition revolver shooting.^{[citation needed]} He is married to Kay Clark Miculek, herself an accomplished shooter, holding numerous national and world titles.

In addition, Miculek is an experienced gunsmith who tunes and adjusts his own revolvers for optimum function.

He is endorsed by Smith & Wesson, who created the S&W Model 625JM model in honor of him.

An avid shooter, Jerry holds numerous national and world shooting titles:^{[citation needed]}

Miculek also demonstrated the ability to fire five shots from a revolver on target with a S&W Model 64 ported barrel revolver in 0.57 seconds on September 25, 2003. This nearly matches the record held by Ed McGivern of 0.45 sec (first shot on 9/13/1932, reproduced 4 times on 12/8/1932). Originally recorded as "two-fifths of a second", the resolution of the timing equipment in 1932 was only 1/20th of a second, so the actual figure could have been anywhere between 0.40 and 0.45 seconds.^{[citation needed]}