4 × 100 metres relay

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.

World championship

A world championship is generally an international sports competition open to elite competitors from across the world, representing their nations, and winning such an event will be considered the highest or near highest achievement in the sport or contest.

The title is usually awarded through a combination of specific contests or, less commonly, ranking systems (e.g. the ICC Test Championship), or a combination of the two (e.g. World Triathlon Championships in Triathlon). This determines a 'world champion', who or which is commonly considered the best nation, team, individual (or other entity) in the world in a particular field, although the vagaries of sport ensure that the competitor recognised at the best in an event is not always the 'world champion' (see Underdog).

Certain sports do not have a world championship, instead they may organise a world cup competition, or they may organize both. Often, the use of the term cup or championship in this sense is just a choice of words. Some sports have multiple champions because of multiple organizations such as mixed martial arts, boxing and wrestling.

IAAF World Championships

IAAF World Championships may refer to any of the World Championship events organized by the IAAF:

2015 World Championships in Athletics

The 15th World Championships in Athletics were held 22–30 August 2015 in Beijing, China. 43 nations won medals, 144 of which were awarded. Kenya topped the medal table for the first time, with 7 gold, 6 silver and 3 bronze medals. The United States won 18 medals, six gold, six silver and six bronze, which was the highest tally. Host nation China, finished 11th on the medals table, while Russia, the overall winner and host in 2013, finished ninth.

205 IAAF member countries and territories participated, two more than in 2013, with new IAAF member, Kosovo, making its debut. South Sudan was also set to participate for the first time, but its sole athlete did not show up in Beijing.

Eritrea won their first world title at these championships, with Ghirmay Ghebreslassie winning the men's marathon.

The event was the largest sporting event to take place at the Beijing National Stadium ("Bird's Nest") since the 2008 Summer Olympics.

Bidding process

When the seeking deadline passed on 15 March 2010, three candidate cities (Beijing, London and Chorzów) had confirmed their candidatures. London then withdrew citing that they didn't want to seem to be biased towards the bids for the Olympic Stadium by committing themselves to an athletics event, as the host for this event was to be announced before their 2011 stadium bid deadline. London then stated that they would bid for 2017 and had the blessing of the IAAF to do so. The IAAF announced Beijing as the winning candidate at the IAAF Council Meeting in Monaco on 20 November 2010. The Council of IAAF approved the dates of 22 August until 30 August 2015.

Usain Bolt

Usain St. Leo Bolt, OJ, CD (/ˈjuːseɪn/; born 21 August 1986) is a Jamaican sprinter. Regarded as the fastest person ever timed, he is the first man to hold both the 100 metres and 200 metres world records since fully automatic time measurements became mandatory in 1977. Along with his teammates, he also set the world record in the 4×100 metres relay. He is the reigning Olympic champion in these three events, and the first man since Leonidas of Rhodes to win six Olympic gold medals in sprinting, and an eleven-time World champion. He was the first to achieve the "double double" of winning 100 m and 200 m titles at consecutive Olympics (2008 and 2012), and topped this through the first "double triple" (including 4×100 m relays).

Although gaining worldwide popularity for a sprint double victory at the Beijing Games, Bolt has had more victories as a 200 m runner. While he had not won any significant 100 m title prior to the 2008 Olympics, he had won numerous crowns in the 200 m event at the youth, junior and senior levels. Further, at the 2013 World Championships in Moscow, Bolt completed a hat-trick of 200 m world titles by winning his third straight gold in the event. His 2009 record breaking margin for 100 m, from 9.69 seconds (his own previous world record) to 9.58, is the highest since the start of fully automatic time measurements.