Olympics guide: Swimming

After finding out that doggy paddle was a legitimate stroke in the freestyle event we were getting out our Speedos. However, after finding out the length of an Olympic swimming pool we were putting them away again. If you're less scared of the deep end than us, follow the guide below.

Athletes: 850

Golds up for grabs: 34

Olympic presence: Men, 1896–present; women, 1912–present

Olympic Format: Men and women both contest fourteen individual races and three team relay races.

Contenders: Americans and Australians won eighteen gold medals at Beijing, though American Michael Phelps, who has been out of sorts, will be hard pressed to retain his eight titles. Britain’s double gold medallist, Rebecca Addlington (400m and 800m freestyle) will be locked in a duel with Italian world champion Federica Pellegrini, while Japan’s Kosuke Kitajima, king of men’s breaststroke, will be aiming for a third double gold in a row. Brazilian Cesar Cielo Filho is defending the men’s 50m freestyle after time out for failing a drugs test.

Past Champions: USA : 214 | Australia: 56 | East Germany: 38

Watch it: 28 July–4 Aug 2012, Aquatics Centre, Olympic Park. Catch the BBC’s coverage of the Olympic Games across 24 dedicated channels on freesat

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THE BASICS

For freestyle there are five races – 50m, 100m, 200m, 400m and 1500m (800m for women). All the other strokes are raced over 100m and 200m. In 2008 the first 10km marathon was contested. Swum in open water, the 2012 competition will be held in the Serpentine Lake in Hyde Park.

(Pictured: the rules in an Olympic swimming pool)

Breaststroke

Breaststroke is a two-part stroke: a frog-like kick of the legs is followed by an arm movement sweeping the water behind the swimmer. The oldest of the four racing strokes, it was often depicted and described in ancient art and literature, and was often depicted and described in ancient art and literature, and was practised with the swimmer’s head out of the water. Over the years swimmers have increased their speed by keeping the head submerged as much as possible.

At the 1956 Olympics Japanese gold medallist Masaru Furukawa swam entire lengths without surfacing. While this raised speeds it also led to oxygen deprivation and health concerns. Under modern rules, the head must break the surface on every full stroke, although the swimmer is allowed just one stroke underwater after turning.

Butterfly

In the 1930s American breaststroke swimmers at the University of Iowa began to experiment with a new action in which the arms were brought through the air together, over the head and into the water, rather than being pushed through the water. This was combined with a newly invented dolphin or fin-tail kick. First seen at the 1936 Olympics, the butterfly stroke proved faster than traditional breaststroke within two years, and in 1952 it was codified as a separate event.

Backstroke

Backstroke began life as a very genteel affair with both hands brought up and over the head simultaneously and then pulled through the water to propel the swimmer. But at the 1912 Olympics American backstroker Harry Hebb powered the competition aside with the straight-armed, alternate arm stroke that is still used today. In the 1930s Australian swimmers worked out that a bent arm under water was better than a straight arm. At the 1988 Seoul Games the Japanese swimmer Diachi Suzuki and the American David ‘Blast-Off’ Berkoff blew their competition away by swimming up to 30m under water using a butterfly kick. The technique was promptly banned. Today, underwater backstroke swimming is restricted to 15m after turning.

Freestyle (crawl)

Any kind of stroke is allowed in freestyle races – you could use sidestroke or doggy paddle if you chose – but as front crawl is the fastest stroke that’s what everyone uses. As with backstroke, 15m of underwater swimming is allowed per length in Olympic freestyle racing. Widely practised in the Pacific and South America, it was first seen in Britain in 1848 when an ex-army officer and impresario called Rankin brought a troupe of Ojibwa Indians to London. In Holborn Baths two of their number – The Flying Gull and Tobacco – took on one of the London swimming ‘Professors’, a Mr Harold Kenworthy.

After giving a long display in the water, in which The Times saw them ‘lash the water violently with their arms like the sails of a windmill’, the Americans were soundly beaten by the fresher Kenworthy, doing the breaststroke. Disconcerted by the inelegance of the crawl, the British persisted with breaststroke, and it fell to the Americans to modernise the technique. Charles Daniels, American gold medallist at the 1904 Games, was an early exemplar, and at the 1912 Olympics the Hawaiian swimmer Duke Kahanmoku introduced the world to the six-kicks-a-cycle technique, in which the kick starts from the hips, producing more power.

Medleys & Relays

There are two individual medley events, the 200m and 400m, in which each swimmer must swim four sequences of 50m or 100m in the following order: butterfly, breaststroke, backstroke, freestyle.

Finally, there are the team relay races in which swimmers take it in turns to compete. These races are the 4 x 100m freestyle, the 4 x 200m freestyle and the 4 x 100m medley, in which each of the four members of the team swims a different stroke in the same order as the individual medley.

(Image: Rex Features)