Swimming

Swimming is the movement by humans or animals through water, usually without artificial assistance. Swimming is an activity that can be both useful and recreational. Its primary uses are bathing, cooling, travel, fishing, escape, and sport.

Animals with lungs have an easier time floating than those without. Almost all mammals can swim by instinct, including bats, kangaroos, moles and sloths. The few exceptions include apes and possibly giraffes and porcupines. Land birds can swim or float for at least some time. Ostriches, cassowaries and tortoises can swim. Juvenile penguins drown if they accidentally fall in water since their down cover is not suited to water.

History
Swimming has been known since prehistoric times; the earliest record of swimming dates back to Stone Age paintings from around 7,000 years ago. Written references date from 2000 BC. Some of the earliest references include the Gilgamesh, the Iliad, the Odyssey, the Bible (Ezekiel 47:5, Acts 27:42, Isaiah 25:11), Beowulf, and other sagas. In 1538, Nikolaus Wynmann, a German professor of languages, wrote the first swimming book, The Swimmer or A Dialogue on the Art of Swimming (Der Schwimmer oder ein Zwiegespräch über die Schwimmkunst). Competitive swimming in Europe started around 1800, mostly using breaststroke. In 1873 John Arthur Trudgen introduced the trudgen to Western swimming competitions, after copying the front crawl used by Native Americans. Due to a British disregard for splashing, Trudgen employed a scissor kick instead of the front crawl's flutter kick. Swimming was part of the first modern Olympic games in 1896 in Athens. In 1902 Richard Cavill introduced the front crawl to the Western world. In 1908, the world swimming association, Fédération Internationale de Natation (FINA), was formed. Butterfly was developed in the 1930s and was at first a variant of breaststroke, until it was accepted as a separate style in 1952.

Non-aquatic animals
Humans do not swim instinctively, but nonetheless feel attracted to water, showing a broader range of swimming movements than other non-aquatic animals (Bender 1999: 119-169). In contrast, many monkeys can naturally swim and some, like the proboscis monkey, crab-eating macaque, and Rhesus macaque swim regularly.



Some breeds of dog swim recreationally. Umbra, a world record-holding dog, can swim 4 miles (6.4 km) in 73 minutes, placing her in the top 25% in human long-distance swimming competitions. Although most cats hate water, adult cats are good swimmers. The fishing cat is one wild species of cat that has evolved special adaptations for an aquatic or semi-aquatic lifestyle – webbed digits. Tigers and some individual jaguars are the only big cats known to go into water readily, though other big cats, including lions, have been observed swimming. A few domestic cat breeds also like swimming, such as the Turkish Van. In an unpublished research carried out 2002 at the University of Bern (Switzerland), Bender & Hirt showed that the Turkish Van has less inhibition to enter in shallow water compared to another breed, the Russian Blue. This behavior can be partially explained by the character of the Turkish Van, who seems to be more curious and enterprising than other cat breeds (see Widmer 1990).

Horses, moose, and elk are very powerful swimmers, and can travel long distances in the water. Elephants are also capable of swimming, even in deep waters. Eyewitnesses have confirmed that camels, including Dromedary and Bactrian camels, can swim, despite the fact that there is little deep water in their natural habitats.

Both domestic and wild rabbits can swim. Domestic rabbits are sometimes trained to swim as a circus attraction. A wild rabbit famously swam in an apparent attack on U.S. President Jimmy Carter's boat when it was threatened in its natural habitat.

The Guinea pig (or cavy) is noted as having an excellent swimming ability. Mice can swim quite well. They do panic when placed in water, but many lab mice are used in the Morris water maze, a test to measure learning. When mice swim, they use their tails like flagella and kick with their legs.

Many species of snakes are aquatic and live their entire lives in the water, but all terrestrial snakes are excellent swimmers as well. Large adult anacondas spend the majority of their time in the water, and have difficulty moving on land. Many beetles are able to swim; some species of diving beetle spend most of their time in the water.

Competitive swimming
The goal of competitive swimming is to be the fastest over a given distance. Competitive swimming became popular in the nineteenth century, and comprises 36 individual events – 18 male events and 18 female events, however the IOC only recognizes 34 events – 17 male and 17 female events. Swimming is an event at the Summer Olympic Games, where male and female athletes compete in 13 of the recognized events each. Olympic events are held in a 50 meter pool. Competitive swimming's international governing body is FINA (Fédération Internationale de Natation), the International Swimming Federation.

The four competitive strokes are the butterfly, backstroke, breaststroke, and front crawl (freestyle). "Freestyle" and "front crawl" are often used interchangeably, but "freestyle" properly refers to an unregulated competitive event rather than to any particular stroke. Swimmers generally choose to swim front crawl in a freestyle event since it is the fastest stroke. In events that require specific strokes, disqualification will occur if the stroke is not swum correctly, for example if the swimmer does not touch the wall with two hands during breaststroke or butterfly.

These strokes can be swum individually or together in an individual medley (IM). The IM order is: 1) butterfly, 2) backstroke, 3) breaststroke, and 4) freestyle. There are two types of relays: medley and freestyle. The medley relay has a different stroke order. In the medley, the order is: 1) backstroke, 2) breaststroke, 3) butterfly, and 4) freestyle. Each of the four swimmers in the relay swims a predetermined distance, dependent on the overall length of the relay. The three relay lengths are 200 meters or yards, 400 meters or yards, and 800 meters or yards (which is only swum freestyle). In a 50 meter pool, each swimmer swims one length for the 200 relay, two lengths for the 400 relay, and four lengths for the 800 relay. In a 25 meter or yard pool, each swimmer swims two lengths for the 200 relay, four lengths for the 400 relay, and eight lengths for the 800 relay. There have also been 100 yard relays that have been done by eight and under swimmers, but is very rare except in summer recreation leagues. Many full-size competition pools in the United States have a length of 50 meters and a width of 25 yards (the Olympic pool size, allowing both short course (25 m or 25 yd pool) and long course (50 m pool) races to be held.

There are several types of officials :
 * A starter sends the swimmers off the blocks and may call a false start if a swimmer leaves the block before the starter sends them;
 * finish judges determine the order of finish and make sure the swimmers finish in accordance with the rules (two hands simultaneously for breaststroke and butterfly, on the back for backstroke, etc.)
 * turn judges check that the swimmers' turns are within rules;
 * stroke judges check the swimmers' strokes;
 * timekeepers time the swims;
 * the referee takes overall responsibility for running the race and makes the final decisions

If an official catches a swimmer breaking a rule concerning the stroke he or she is swimming, that swimmer is said to be disqualified (commonly referred to as a "DQ") and the swim is not considered valid.

Masters swimming is a club sport for adults who have a competitive spirit. Swimming at this level differs from competitive club swimming. In swim meets masters are allowed to compete in the 50, 100 and 200 of backstroke, fly and breaststroke and the 50, 100, 200, 500 and 1650 of freestyle. The age groups are organized into five-year increments (Masters, 1). “Swimming has continually been identified as the best way to exercise. Stress reduction, weight control, cardiovascular fitness, reduced cholesterol, muscle tone and endurance are all positively influenced by exercise. Masters Swimmers swear by it (Masters, 1).” Shoulder injuries are the most common because of the repetitive motion of freestyle, butterfly, and backstroke. Knee injuries often occur from breaststroke due to the unnatural kick. Incorrect stroke technique can also lead to injuries.

Recreational swimming
The most common purpose for swimming is recreation. Recreational swimming is a good way to relax, while enjoying a full-body workout. Several swimming styles are suitable for recreational swimming; most recreational swimmers prefer a style that keeps their head out of the water and has an underwater arm recovery. Breaststroke, side stroke, head up front crawl and dog paddle are the most common strokes utilized in recreational swimming, but the out-of-water arm recovery of freestyle or butterfly gives rise to better exploitation of the difference in resistance between air and water.



The butterfly stroke, which consists of out-of-water recovery with even symmetry in body movements, is most suited to rough water swimming. For example, in a record-setting example of endurance swimming, Vicki Keith crossed the rough waters of Lake Ontario using butterfly. Most recreational swimming takes place in swimming pools, and calm natural waters (sea, lakes, rivers), therefore front crawl is suitable.

Occupational swimming
Some occupations require the workers 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. In the USA, most cities and states have trained lifeguards, such as the Los Angeles City Lifeguards, deployed at pools and beaches. There are a number of specialized swimming styles especially for rescue purposes (see List of swimming styles). Such techniques are studied by lifeguards or members of the Coast Guard. The training for these techniques has also evolved into competitions such as surf lifesaving.

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

Swimming also has military purposes. 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 exiting a submarine while it is submerged. Due to regular exposure to large bodies of water, all recruits in the United States Navy, Marine Corps, and Coast Guard are required to complete basic swimming or water survival training.

Swimming is also a professional sport. Companies such as Speedo, TYR Sports, Arena and Nike sponsor swimmers who are at the international level. Cash awards are also given at many of the major competitions for breaking records.

Swimming as exercise
Swimming is an excellent form of exercise. Because the density of the human body is very similar to that of water, the water supports the body and less stress is therefore placed on joints and bones. Swimming is frequently used as an exercise in rehabilitation after injuries or for those with disabilities.

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 moving water (often termed a swimming machine) or by holding the swimmer stationary with elastic attachments.

Swimming is primarily an aerobic exercise due to the 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 swimming is believed to reduce the harmful effects of stress. Swimming can improve posture and develop a strong lean physique, often called a "swimmer's build."

The risks of swimming
Swimming is a healthy activity that has minimal impact on the joints. A swimmer benefits from a low risk of injury compared with many other sports. Nevertheless, there are some health risks with swimming, including the following:


 * Drowning, inhalation of water arising from
 * Adverse water conditions swamping or overwhelming the swimmer or causing water inhalation.
 * 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 foam in the lungs that restricts breathing.
 * Salt water aspiration syndrome.
 * 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 Swimmer's ear.)


 * Exposure to chemicals
 * Disinfectant Chlorine will increase the pH of the water, if uncorrected the raised pH may cause eye or skin irritations.
 * 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, particularly for asthmatics. This problem may be resolved by using a pool with better ventilation, with an outdoor pool having the best results.
 * Chlorine also has a negative cosmetic effect after repeated long exposure, stripping brown hair of all color, turning it very light blonde. Chlorine damages the structure of hair, turning it "frizzy." Chlorine can dissolve copper, which turns blonde hair green. Proper pool maintenance can reduce the amount of copper in the water, while wetting the hair before entering a pool can help reduce the absorption of copper.
 * Chlorine will often remain on skin in an anhydrous form, even after several washings. The chlorine becomes odorous once it is back in an aqueous solution (when salivated on, during a shower, etc.).


 * 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 to dry the space between the toes.
 * 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).
 * When chlorine levels are improperly balanced, severe health problems may result, such as chronic bronchitis and asthma.
 * Swimmer's own actions
 * Overuse injury; competitive butterfly stroke swimmers for example may develop some back pain, including vertebral fractures in rare cases, and shoulder pain after long years of training, breaststroke swimmers may develop knee pain, and hip pain. Freestyle and backstroke swimmers may develop impingement syndrome, a form of tendinitis, commonly referred to as swimmer's shoulder.
 * 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, can pull 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.


 * Aquatic life
 * Stings from jellyfish and some corals.
 * Piercings caused by sea urchins, zebra mussels, stingrays.
 * Bites from sharks and other fish and snakes, and pinches from lobsters or crabs.
 * Electrocution from electric rays and electric eels.

Organizations publish safety guidelines to help swimmers avoid these risks.

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

In Sweden, Denmark, Norway and Finland, the curriculum for the fifth grade states that all children should learn how to swim as well as how to handle emergencies near water. 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 both the Netherlands and Belgium swimming lessons under school time (schoolzwemmen, school swimming) are supported by the government. Most schools provide swimming lessons. There is a long tradition of swimming lessons in the Netherlands and Belgium, the Dutch translation for the breaststroke swimming style is even schoolslag (schoolstroke). The children learn a variant of the breaststroke, which is technically not entirely correct.

In many places, swimming lessons are provided by local 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 public pool.

In the UK, 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 metres by the time they leave primary school will be given a half-hour lesson every day for two weeks during term-time.

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


 * Buoyancy
 * Diving
 * Fish locomotion
 * Resistance swimming
 * Total Immersion