4 x 100 metres

The 4 × 100 metres relay or sprint relay is an athletics track event run in lanes over one lap of the track with four runners completing 100 metres each. The first runners must begin in the same stagger as for the individual 400 m race. A relay baton is carried by each runner and must be passed within a 20 m changeover box (usually marked by yellow lines) which extends 10 m on either side of each 100 m mark of the race. Another line is marked 10 m further back, marking the earliest point at which the outgoing runner may begin (giving up to 10 m of acceleration before entering the passing zone).

Transferring of the baton in this race is typically blind. The outgoing runner reaches a straight arm backwards when they enter the changeover box, or when the incoming runner makes a verbal signal. The outgoing runner does not look backwards, and it is the responsibility of the incoming runner to thrust the baton into the outstretched hand, and not let go until the outgoing runner takes hold of it. Runners on the first and third legs typically run on the inside of the lane with the baton in their right hand, while runners on the second and fourth legs take the baton in their left. Polished handovers can compensate for a lack of basic speed to some extent, and disqualification for dropping the baton or failing to transfer it within the box is common, even at the highest level.

The United States men historically dominated this event through the 20th Century, having won 15 Olympic gold medals and 5 IAAF world championships. Carl Lewis ran the anchor leg on five U.S relay teams that broke the World Record from 1983–92, the first team to break 38 seconds.

The current men's world record stands at 36.84 as set by the Jamaican team at the 2012 London Olympic games on 11 August 2012. As the only team to break 37 seconds to date, Jamaica has been the dominant team in the sport, winning 3 consecutive Olympic Gold Medals as well as 4 consecutive World Championships. The previous record was 37.04 seconds as set by the Jamaican team at the 2011 World Championships.

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