Swimming

This article concentrates on human swimming. For other species, see The ability to swim. For floating of inanimate objects see Buoyancy

A breaststroke swimmer

Swimming is a technique that humans, and other animals, use to move through water using only movements of the body. This article concentrates on human swimming, a recreational activity and a competitive sport. There are health benefits of swimming, but it also entails risks.

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 introduced 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 1900 backstroke was included as an Olympic Event. In 1902 the trudgen was improved by Richard Cavill, using the flutter kick. In 1908, the world swimming association Federation Internationale de Natation (FINA) was formed. Butterfly was first a variant of Breaststroke, until it was accepted as a separate style in 1952.

Technique

Main article: The ability to swim

The human body is composed primarily of water, and thus has a very similar density to water. Since only roughly 70% of the body is water, it is slightly less dense than the surrounding water, which exerts a buoyant force on it. 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 intended motion. This propelling is accomplished by cupping the hands and using them as paddles, and by kicking the legs to push water away from the body.

A number of swimming styles have been developed based on the implementation of some or all of the following principles:
The torso and the legs should be kept as parallel as possible to the surface of the water. Dropped legs or a slanted torso dramatically increase drag. The hand should be extended forward of the head as much as possible. This increases the average length at the water-line, substantially increasing speed.

The time spent on the side should be maximized because the torso is narrower 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 body's 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 the back to the front should be in the air for 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 (which 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. 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 beginners, increased strength brings only small improvements if the above strategies (minimising drag and lengthening water-line) are not optimal.

Competitive swimming

The goal of competitive swimming is to swim the fastest for a given distance. Competitive swimming became popular in the nineteenth century, and currently comprises 34 events - 17 male events and 17 female events. Swimming is a popular event at the Summer Olympic Games, where male and female athletes compete in 13 of the recognized events each. Competitive swimming's international governing body is FINA (Fédération Internationale de Natation), the International Swimming Federation. It is currently being debated whether or not to instate the 1500 metres freestyle as part of the female events. Currently, the longest female event is the 800 metres freestyle.

The four competitive strokes are the butterfly, backstroke, breaststroke, and freestyle. These strokes can be swum individually or together in an individual medley (IM). The order an IM goes in is: 1) butterfly, 2) backstroke, 3) breaststroke, and 4) freestyle. There is also the medley relay in which the order is: : 1) backstroke, 2) breaststroke, 3) butterfly, and 4) freestyle. Each of the four swimmers in the relay swims one or two length of the pool.

In the United States and Great Britain. many communities sponsor competitive swimming leagues (for children and young people aged 4-18), made up of individual swim teams, which may range in size from a few dozen swimmers to several hundred swimmers. These leagues for the most part adhere to recognized swimming rules, swim the standard strokes, but swim shorter lengths as events in swim meets. These leagues are usually active in the warmer months, and are not directly associated with a national or world swim organization. However, some swimmers who begin their competitive swimming experience on such a local swim team go on to join a nationally-governed team, on their path to an Olympic berth later.

Recreational swimming

Two swimming docks.

The most common reason for swimming is recreation, where the swimmer enters the water merely for enjoyment. Swimming is a good way to relax. Many swimming styles are suitable for recreational swimming. Most recreational swimmers prefer a style that keeps their head out of the water and with an underwater arm recovery. For example, breaststroke, side stroke, 'dog paddle', or treading water. However, out-of-water recovery of freestyle or Butterfly gives rise to better exploitation of the difference in viscosity of the two media (air and water). Butterfly, which consists of out-of-water recovery with even symmetry in body movements, is most suited to rough water swimming. For example, Vicki Keith crossed the rough waters of Lake Ontario using butterfly. Most recreational swimming takes place in pools, where the water is calm. Therefore freestyle (which does not work as well in rough water) is suitable. Venues for recreational swimming are Swimming Pools, beaches, lakes, swimming holes, creeks, rivers, and sometimes canals.

Occupational swimming

Some occupations require the worker to swim. For example, abalone divers or pearl divers swim and dive to obtain an economic benefit, as do spear fishermen.

Swimming is used to rescue other swimmers in distress. There are a number of specialized swimming styles specially for rescue purposes (see List of swimming styles). Such techniques are studied by lifeguards or members of the Coast Guard. The training of these techniques has also evolved into competitions such as surf lifesaving.

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

Swimming also has military purposes. 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, such as 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 has more recently become a professional sport as well. Companies such as Speedo and Tyr Sports, Inc. sponsor swimmers just as Nike sponsors basketball players. Cash awards are also given at many of the major competitions for breaking records.

Swimming for exercise

File:Swimergy hybrid swim machine.jpg

A still-water swimming machine where the swimmer exercises against the pull of a bungee cord.

Swimming is a good form of exercise. Because the density of the human body is approximately similar to that of water, the body is supported by the water and less stress is therefore placed on joints and bones. Therefore, swimming is frequently used as an exercise in rehabilitation after injuries or for the disabled.

Resistance swimming is one form of swimming exercise. It is done either for training purposes, to hold the swimmer in place for stroke analysis, or to enable swimming in a confined space for athletic or therapeutic reasons. Resistance swimming can be done either against a stream of water set in motion by a (usually) self-contained mechanical device (often termed a swimming machine) or by holding the swimmer stationary by means of elastic attachments.

Swimming is primarily an aerobic exercise due to the relatively long exercise time, 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 food energy to maintain body temperature.

The reason that swimming does not significantly reduce weight is still poorly understood, but seems to be related to the better heat conduction of water. A number of reasons are suspected.

• Firstly, water cools the body much faster than air and most researchers believe that subsequently the body aims to maintain a layer of fat under the skin for insulation.
• Secondly, it is believed that appetite decreases as your body temperature increases, as for example during exercise. However, during swimming the body is cooled down almost instantly as the surrounding water is usually cooler than the body temperature, and some researchers believe that this may actually increase the appetite. This assumption is not yet proven by research.
• Thirdly, fast swimming requires a high level of effort, meaning glycogen rather than fat is burned. Prolonged exercise at lower intensity is better for fat-burning.
• Fourthly, some researchers also believe that the metabolism of the body increases at higher body temperature, burning more food energy. Again, during swimming the body is cooled down by the surrounding water, reducing the metabolism, and subsequently the amount of food energy burnt. This assumption is also not yet proven by research.
• Finally, there is also a theory that people with a genetically higher body fat content tend to be more successful as swimmers since the increased buoyancy of the fat aids in floatation or the rounder shapes offer less resistance to the water.

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

Sometimes the swimming consists of swimming laps using a conventional stroke, such as the front crawl; other forms can include different forms of exercise performed in the water, such as water aerobics.

Swimming may be good for asthma sufferers.

Swimming uses all three energy systems, which are the creatine phosphate system, anaerobic glycolysis (also known as Lactic acid system), and the aerobic system. These three systems require energy in form of ATP to function.

The risks of swimming

A sign warns hikers on the trail to Hanakapiai Beach.

Swimming is generally a healthy activity and enjoys a low risk of injury compared with many other sports. Nevertheless there are some health risks with swimming, including the following:

• Drowning, inhalation arising from:
  • Adverse water conditions swamping or overwhelming the swimmer or causing water inhalation.
  • Negative buoyancy when attached to a heavy object or entrapment e.g. in a sinking ship.
  • Actions of others pushing under water accidentally in play or intentionally.
  • Exhaustion or unconsciousness.
  • Incapacitation through shallow water blackout, heart attacks, carotid sinus syncope or stroke.

• Adverse effects of immersion
  • Secondary drowning, where inhaled salt water creates a foam in the lungs that restricts breathing.
  • Salt Water Aspiration Syndrome, SWAS.
  • Thermal shock after jumping into water can cause the heart to stop.
  • Exostosis which is an abnormal growth in the ear canal due to the frequent, long-term splashing of water into the ear canal. (Known as Surfer's ear or Swim ear)
  • Injuries may heal more slowly if submerged in water.

• Exposure to chemicals
  • Chlorine in the eyes; in chlorinated swimming pools the chlorine may burn the eyes, stopping shortly after leaving the water but may be persistent and serious. Other disinfection techniques using, for example, ozone can avoid this effect.
  • Chlorine inhalation; breathing small quantities of chlorine gas from the water surface whilst swimming for long periods of time may have an adverse effect on the lungs.
  • Chlorine also has a negative cosmetic effect after repeated long exposure, turning blonde hair green and turning teeth brown.

• Infection
  • Water is an excellent environment for many bacteria, parasites, fungi and viruses affecting humans depending on water quality.
  • Skin infections from both swimming and shower rooms can cause athlete's foot (boat bug). The easiest way to avoid this is drying the space between the toes after swimming.
  • Microscopic parasites such as Cryptosporidium can be resistant to chlorine and can cause diarrheal illness when swimmers swallow pool water.
  • Ear infections, otitis media, (otitis externa).
  • Legionnaires' disease may have been transmitted by showers after swimming. Heating the shower water to 60 °C (140 °F) once per week during closing time will disinfect the water system.

• Swimmer's own actions
  • Overuse injury; competitive butterfly stroke swimmers for example may develop some back pain and shoulder pain after long years of training, breaststroke swimmers may develop knee pain, and front crawl and backstroke swimmers may develop shoulder pain, commonly referred to as swimmer's shoulder (a form of tendonitis).
  • Hyperventilation in a bid to extend underwater breath-hold times lowers blood carbon dioxide resulting in suppression of the urge to breathe and consequent loss of consciousness towards the end of the dive, see shallow water blackout for the mechanism.

• Adverse water and weather conditions
  • Currents, including tides and rivers can cause exhaustion, move swimmers away from safety, or pull swimmers under water.
  • Wind enhances waves and can blow a swimmer off course.
  • Hypothermia, due to cold water, can cause rapid exhaustion and unconsciousness.
  • Sunburn severity can be increased by reflections in the water and the lack of clothing worn during swimming. Long-term exposure to the sun contributes to risk of skin cancer.

• Objects in the water.
  • Propeller damage is a major cause of accidents, either by being run over by a boat or entanglement on climbing into a boat.
  • Collision with another swimmer, the pool walls, rocks or boats.
  • Diving into a submerged object, or the bottom, often in turbid water.
  • Snagging on underwater objects, particularly submerged branches or wrecks.
  • Stepping on sharp objects such as broken glass.

• Dangerous aquatic life
  • Stings, jellyfish and some corals.
  • Piercings, sea urchins, zebra mussels
  • Bites, sharks and other fish, snakes, lobster or crabs.
  • Electrocution, electric rays, electric eels.

Swimming lessons

Children are often given formal swimming lessons, which serve to develop swimming technique and confidence. Children generally do not swim independently until 4 years of age.

In Sweden the curriculum for the fifth grade states that all children should learn how to swim as well as how to handle emergencies near water, with the exact definition varying from school to school. Most commonly, children are expected to be able to swim 200 metres (220 yards) – of which at least 50 metres (55 yards) on their back – after first falling into deep water and getting their head under water. Even though about 95 percent of Swedish school children know how to swim, drowning remains the third most common cause of death among children.

In the UK, swimming lessons are provided by many swimming pools, both those run by the local authority and by private leisure companies. Many schools also include swimming lessons into their Physical Education curricula, provided either in the schools' own pool, or in the nearest publicly accessible pool.

Recently, in the UK, a new plan called the "Top-ups scheme" calls for school children who cannot swim by the age of 11 to receive intensive daily lessons. These children who have not reached Great Britain's National Curriculum standard of swimming 25 meters by the time they leave primary school will be given a half-hour lesson every day for two weeks during term-time.

In Canada there has been a call for swimming to be included in the public school curriculum.

Clothing

Boys skinny dipping in a sacred tank of water in India.

Modesty led to the development of the swimsuit (and in Victorian times, the bathing machine).

Men's swimsuits tend to be trunks, surf or boardshorts, competition briefs, or cut-offs. Almost always, the upper body is left uncovered. In the early part of the 20th century, it was illegal for men to be topfree in the USA.

Women's swimsuits are generally either one-piece swimsuits of traditional or competitive style (such as the racerback) or bikinis. Another option would be a Tankini, more conservative than a bikini but still not a one-piece. In some areas, women have the choice or make the choice of going topfree.

Bodyskins are special whole body swimsuits for competitive swimming, designed to reduce skin drag. (See Competitive swimwear)

Nude swimming is done:

• at nudist/naturist areas such as resorts or clubs
• some intentional communities also allow nudity
• nude beaches, in the context of public nudity
• without being formally allowed, at quiet places and hours; also called skinny dipping
• at private swimming pools and beaches, not visible to outsiders
• during naturist/nudist hours in some swimming pools
• at special public events such as World Naked Bike Ride and Nackt Radtour
• Beach wade-ins, Polar Bare Dips
• Night swimming is sometimes done at public beaches in small groups.
• at (usually small) swimming pools in saunas
• in Denmark, all beaches are clothing-optional unless marked otherwise

Bibliography

• Maniscalco F., Il nuoto nel mondo greco romano, Naples 1993.
• Mehl H., Antike Schwimmkunst, Munchen 1927.
• Sprawson, Charles (2000). Haunts of the Black Masseur - The Swimmer as Hero. University of Minnesota Press. ISBN 0816635390.
• Tarpinian, Steve (1996). The Essential Swimmer. The Lyons Press. ISBN 1558213864.
• Cox, Lynne (2005 by Harvest Books). Swimming to Antarctica: Tales of a Long-Distance Swimmer. 2005 by Harvest Books. ISBN 0156031302. {{cite book}}: Check date values in: |year= (help)

External links

• Drowning Prevention and Water Safety Information from Seattle Children's Hospital and the Washington State Drowning Prevention Network.
• How to swim (An archaic but very interesting article from the Boy's Own Book of Outdoor Sports (early 1900s))
• Swimming Injuries and Illnesses
• Swim Sites - Swimming web directory
• Swimming and Weight Loss
• SWIMMERS: Body fat mystery!
• Swimming Tips and News for All Abilities

See also

• Deep Eddy Pool—Oldest swimming pool in Texas
• Diving
• Fish locomotion
• Ice swimming
• List of swimming styles
• List of Swimmers
• List of swimming coaches
• List of water sports
• Resistance swimming
• Swimming at the Summer Olympics
• Swimming machine
• Swimming pool
• Total Immersion