Swimming: Difference between revisions

''This article concentrates on human swimming. For other species, see [[Ability to swim]].''

Swimming was part of the first modern [[1896 Summer Olympics|1896 Summer Olympics games]] 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 was formed. Butterfly was first a variant of Breaststroke, until it was accepted as a separate style in 1952.

The time spent on the side should be maximized because so the shoulders do not break the water-line and do not produce [[Bulbous bow|bow waves]]. 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 time during the recovery stroke as possible, and in the water, oriented as hydrodynamically 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. Rotating your shoulders also adds power to one's pull by using  [[http://en.wikipedia.org/wiki/Human abdomen#Muscles of the abdominal wall|abdominal muscles]] to help pull the arm through the water.  

[[Skeletal animation]] and [[computational fluid dynamics]] allow  simulation of swimmers. This allows to quantify forces on joints and muscles, and, if multiple simulations are employed, to compare different styles or individuals. By means of [[computer graphics]] or [[motion capture]] the simulation can be compared to real swimmers. While this removes many doubts, it is still guess work needed to create new styles, it is a didactic challenge to formulate a manual for swimmers, and the feel of the water is still needed to close a [[control loop]] so that the swimming styles does not drift away afterwards (Refs with images:

[[Image:SwimmeetOSU.JPG|thumb|right|300px|A swim meet at [[Ohio State University|The Ohio State University]]]]

The goal of competitive swimming is to be the fastest to swim 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.  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 stroke|butterfly]], [[backstroke]], [[breaststroke]], and [[freestyle swimming|freestyle]](frontcrawl). 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 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 [[meter]]s or [[yard]]s, 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. Many full-size competition pools in the United States have a length of 50 meters and a width of 25 yards, allowing both short course (25 m or 25 [[yard|yd]] pool) and long course (50 m pool) races to be held.

The most common purpose for swimming is recreation. Recreational swimming is considered by many a good way to relax, as well as providing a good full-body workout.  Several [[List of swimming styles|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. [[Breaststroke]], [[side stroke]], and '[[Dog paddle swimming|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.  

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 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 hole]]s, [[Creek (stream)|creeks]], rivers, and sometimes canals.

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 [[lifeguard]]s or members of the [[Coast Guard]]. The training of these techniques has also evolved into competitions such as [[surf lifesaving]].

Swimming also has [[Armed force|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 SEAL|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.  

Swimming is an excellent 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 those with [[disability|disabilities]].

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 [[anaerobic exercise|anaerobically]]. As with most aerobic exercise it is believed to reduce the harmful effects of [[Stress (medicine)|stress]].

** Incapacitation through [[shallow water blackout]], [[myocardial infarction|heart attacks]], [[carotid sinus#Disease of the carotid sinus|carotid sinus syncope]] or [[stroke]].

** [[Salt Water Aspiration Syndrome]], SWAS.

** [[Exostosis]] which is an abnormal growth in the [[ear|ear canal]] due to the frequent, long-term splashing of water into the ear canal. (Known as [[Surfers' ear]] or Swimmers' ear)

** [[Disinfectant]] [[Chlorine]] will increase the [[pH]] of the water, if uncorrected the raised pH may cause eye or skin irritations [http://www.cdc.gov/healthyswimming/ph_chlorine.htm].  

** 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 [[asthma]]tics.  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, turning blonde hair green and stripping brown hair of all color, turning it very light blonde. Chlorine damages the structure of hair, turning it "frizzy."

** Water is an excellent environment for many [[bacterium|bacteria]], [[parasite]]s, [[fungi]] and [[virus]]es 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 [[foot|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]]).

** [[Current (water)|Currents]], including [[tide]]s and rivers can cause exhaustion, move swimmers away from safety, or pull swimmers under water.

** Piercings, [[sea urchin]]s, [[zebra mussels]], [[stingrays]]

** Bites, [[sharks]] and other [[fish]], [[snake]]s, [[lobster]] or [[crab]]s.

In [[Sweden]], Denmark and in 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.<ref name="simtillsyn">{{cite web

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

Men's swimsuits tend to be [[Trunks (clothing)|trunks]], surf or [[boardshorts]], [[Speedo (suit style)|competition briefs]], or more improvised [[cut-off shorts]]. Almost always, the upper body is left uncovered. However, in the early part of the 20th century, it was illegal for men to be topless in the USA.

* [[Diving]]

* [[Lifeguard]]

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