The Swimming reference article from the English Wikipedia on 24-Jul-2004
(provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Swimming

Videos from a children's charity on sponsorship
Swimming is the method by which humans (or other animals) move themselves through water. Swimming is a popular recreational activity, particularly in hot countries and in areas with natural watercourses. Swimming is also a competition sport. There are many health benefits of swimming, yet basic swimming skills and safety precautions are needed to participate in water activities.

The breaststrokeEnlarge

The breaststroke

Table of contents
1 Swimming Purposes
2 Technique
3 Clothing
4 Swimming and health
5 History
6 See also
7 External link

Swimming Purposes

Swimming and related water sports are done for a number of purposes. Often, these purposes can overlap, and a recreational swimmer for example may also swim for health benefits.

Recreational

The most common reason for swimming is probably recreation, where the swimmer enters the water merely for enjoyment. Many swimming styles are suitable for recreational swimming. Most recreational swimmers prefer a style that keeps their head out of the water and uses an underwater arm recovery, for example breaststroke, side stroke, or 'dog paddle'.

Swimming pools are popular venues for recreational swimming, as are beaches, lakes, swimming holes, creeks, rivers, and sometimes canals.

Competition

Competitive swimming is swimming with the goal to maximize performance, usually the speed of swimming. Competitive swimming became popular in the 19th century, and is an event at the Summer Olympic Games. There are four swimming disciplines regulated by the FINA, swum over different distances.

In addition to that there are a number of combination events in Competitive swimming.

Full rules are on the rules web page of FINA.

Competitive swimming has traditionally been dominated by the United States, but recently that dominance has been challenged by Australia, where swimming is a hugely popular recreational activity, and participant and spectator sport. The success of Australian swimmers like Ian Thorpe and Kieren Perkins is reminiscent of Australia's previous golden age of swimming in the 1950s and 1960s, which saw the emergence of swimmers such as Shane Gould and Dawn Fraser.

There are also a number of other Competitive swimming performances, for example a long distance 5 kilometer open-water event, which became part of the Olympic program in 2000, or long distance swims across the English Channel, or circumnavigating Manhattan Island. The world record for the longest nonstop swim is held by Martin Strel for swimming 504km nonstop in 2001 in the Danube River. He also swam the Mississippi River in 2002 in 66+2days, a total of 3885km.


Swimming is also a crucial part of other sports, such as water polo, synchronized swimming and triathlon. (See List of water sports)

Rescue

Swimming is also used for rescue to avoid drowning. Most of the time this will be self rescue, where a person involuntarily enters the water and swims to stay afloat or to reach safety.

In addition to self rescue, swimming is also used to rescue other swimmers in distress. There are a number of specialized swimming styles specially for the purpose of rescuing swimmers in distress (see List of swimming styles). Such techniques are studied for example by lifeguards, or members of the Coast Guard. The training of these techniques also evolved into competitions, as for example surf lifesaving.

Others

A number of people enter the water and swim as part of their work. For example, Abalone divers or pearl divers swim and dive to obtain an economic benefit, as do spear fishermen.

Swimming is also done to advance the sciences. Naturally, swimming is studied to improve the swimming performances of competitive swimmers. But swimming and diving is also often used in marine biology to observe plants and animals in their natural habitat. Other sciences may also use swimming. Konrad Lorenz for example swam with geese as part of his studies of animal behavior.

Often, swimming is used merely as a way to move between locations. Nowadays, bridges and ferries are used most of the time, but there are occasions where swimming is used to move between locations, for example for crossing rivers or accessing islands. Cargo may be carried on the swimmer or pulled, possibly on a flotation device, during the swim. Military troops use swimming to cross waters.

Swimming also has military purposes besides the mere need to cross waters. A swimmer in the water or under the water can be difficult to detect, especially at night. Military swimming is usually done by Special forces, as for example Navy SEALS. Swimming is used to approach a location, gather intelligence, sabotage, or combat, and to depart a location. This may also include airborne insertion into water or leaving a submerged submarine through a hatch or the torpedo tubes. Special equipment and techniques are also used to engage hostiles in and under water.

Swimming is also done for health purposes, as for example rehabilitation after injuries.

Technique

The human body, being composed mostly of water, has nearly the same density as water. Thus, staying afloat requires only a slight propelling of water downward relative to the body, and transverse motion only a slight propelling of water in a direction opposite to the direction of motion, due to generally low hydrodynamic drag. This propelling is typically accomplished by cupping the hands and using them as paddles, and by kicking the legs to push water away from the body.

With practice, technique can convert a slow or average swimmer to at least a moderately fast swimmer. Since speed converts directly into distance, the same techniques that improve speed also aid one to move farther with the same effort.

The torso and the legs should be kept as much as possible parallel to the surface of the water. Drooped legs or a slanted torso dramatically increase drag.

Try to have a pointed hand above the head, pointed forward as much as possible. This increases the average length at the water-line, substantially increasing speed. This is an effect long used by boat designers, and unconsciously used by "naturally good swimmers."

Try to maximize the time spent on the side because the torso is smaller front-to-back than side-to-side on most swimmers. This reduces the frontal cross-section, reducing drag further, and also increasing the ratio between the bodies water-line-length and width. Similar improvements are possible by orienting the narrowest direction of head, hands, legs and arms into the water. The torso is by far the most critical.

The motion of the hand, arm, and leg from back to the front should be in the air as much as possible, and in the water, oriented as perfectly as possible, because the returning appendage has to move at least twice as fast as the swimmer, and in the water generates eight times the drag (drag increases with the cube of the speed) of an equal amount of torso frontal area.

The basic "catch" of the water is not nearly as critical as the above items. Most swimmers simply grab water with their hand flat, or the fingers slightly spread, and then draw it smoothly down their body.

Note that none of the above techniques require improved strength. With strength training, the hands and feet can be extended further into the water, gaining more propulsion. For improvers, increased strength brings only small improvements if the above strategies (minimise drag and lengthen water-line) are not optimal.

A number of swimming styles have been developed based on the implementation of some or all of these principles.

Clothing

The desire or cultural demand of modesty together with the awkwardness or unsuitability of conventional clothing in the water led to the development of the swimsuit (and in Victorian times, the bathing machine).

Men's swimsuits tend to be trunks, surf or board shorts, competition briefs, cut-offs, or jeans. The famous 'top and levis' -- a neoprene jacket and shrink-to-fit Levis remains one of the best diveskins, offering protection from overexposure to the sun, stings, and abrasion. Levis 501, 505 and 512 Red Tab have a hydrodynamic fit for swimming and diving. Levis have been featured in a variety of under-water commercials: The Mermaid, The Levis Swimmer, The French Dictionary, and numerous beach commercials in the 1990's. Advertised as 'your second skin', Levis are considered by intrepid swimmers and divers to be an extension of their aquatic body, and became popular starting in the 1960's with the famous 'white levis' worn by surfers.

Women's swimsuits are generally either one-piece swimsuits or bikinis. Also there is the monokini, in case the coverage of the breasts is neither required nor desired. However, special swimsuits for competitive swimming, designed to reduce skin drag, can resemble unitards.

Nude swimming is done:

Swimming and health

Swimming is a good form of exercise. Because the density of the human body is approximately similar to water, the body is supported by the water and less stress is therefore placed on joints and bones. Furthermore, the resistance against movement depends heavily on the speed of the movement, allowing the fine tuning of the exercise according to ones ability. Therefore, swimming is frequently used as an exercise in rehabilitation after injuries or for the disabled.

Swimming exercises almost all muscles in the body. Usually, the arms and upper body are exercised more than the legs, as most forward motion is generated by the arms. In competitive swimming, excessive leg muscles can be seen as a disadvantage as they consume more oxygen, which would be needed for the muscles of the arms. However, this depends very much on the swimming style. While breaststroke generates significant movement with the legs, front crawl propels the body mainly with the arms.

Swimming is an aerobic exercise due to the relatively long exercise times, requiring a constant oxygen supply to the muscles, except for short sprints where the muscles work anaerobically. As with most aerobic exercise it is believed to reduce the harmful effects of stress. While aerobic exercises usually burn fat and help with losing weight, this effect is limited in swimming, even though being in cold water burns more calories to maintain body temperature. The reason while swimming does not significantly reduce weight is still poorly understood, but seem to be related to the better heat conduction of water. A number of reasons are suspected.

Swimming is considered a sport with a low risk of injury. Nevertheless there are some health risks with swimming. Most lethal risks in swimming are due to the inability to swim. It is recommended to swim in an area supervised by lifeguards and to paying attention to the water conditions. Possible health risks range from lethal to minor inconveniences. Below is a list of these risks, ranging from potentially lethal to minor temporary inconveniences.

History

Main article:
History of swimming

Swimming has been known since prehistoric times. Drawings from the stone age were found in "the cave of swimmers" near Wadi Sora (or Sura) in the southwestern part of Egypt. Written references date back up to 2000 B.C, including Gilgamesh, the Iliad, the Odyssey, the Bible (Ezekiel 47:5, Acts 27:42, Isaiah 25:11), Beowulf, and other sagas. In 1538 Nicolas Wynman, German professor of languages, wrote the first swimming book "Colymbetes". Competitive swimming in Europe started around 1800, mostly using breaststroke. The front crawl, then called the trudgen was intruduced in 1873 by John Arthur Trudgen, copying it from native americans. Swimming was part of the first modern Olympic games in 1896 in Athens. In 1902 the trudgen was improved by Richard Cavill, using the flutter kick. In 1908, the world swimming association Federation Internationale de Natation de Amateur (FINA) was formed. Butterfly was first a variant of Breaststroke, until it was accepted as a separate style in 1952.

See also

External link

DISCLAIMER
Please remember that Wikipedia is offered for informational use only. The information is in most cases not reviewed by professionals. You are advised to contact your doctor for health-related decisions.