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Tuesday, June 5, 2007

Where Swimming Started

Drawings from the Stone Age were found in "the cave of swimmers" near Sura in the southwestern part of Egypt. Written references date back up to 2000 B.C. In 1538 Nicolas Wynman, German professor of languages, wrote the first swimming book. 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 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.

Technique

The human body is composed primarily of water, and it has a very similar density to water. Roughly, 70% of the body is water; while the lungs are filled with the air, the body 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 using the hands and forearms as paddles, and by kicking the legs to push water away from the body (though kicking accounts for relatively little overall). Since salt water (e.g., the ocean) is denser than fresh water (e.g., most swimming pools), less effort is required to stay afloat in salt water than in fresh water.

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.

Recent research has shown that hand force applied to the water is really generated by the rotation of the hips, and not by the muscles of the arm. The muscles that pull the arm through the water are attached within one inch of the top of the arm. With a 21" arm, the lever ratio is 1:20, which means that a 100 lbs. of pull by the shoulder muscles produces only 5 lbs. of force at the hand as it pushes back against the water. The torque generated by the larger, stronger hip muscles, on the other hand, whips the hands through the water, much like golfers or batters whip their clubs and bats through the air with a fast turn of the hips. Elite swimmers who were able to make modest increases in the acceleration of their hips doubled their peak hand force output.

The time spent on the side should be maximized so the shoulders do not break the water-line and do not produce 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 abdominal muscles to help pull the arm through the water.

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.

Another technique that can help an athlete swim at a higher performance level is proper breathing techniques. Breathing correctly can make you swim faster and make it harder for you to be fatigued. Competitive swimmers take in one breath and gradually let it out over three to four strokes. As the race progresses and the swimmer becomes tired, less oxygen from those breaths reach his muscles. You can practice and teach your body how to run on less than normal levels of oxygen. Take a deep breath at one side of a pool, submerge yourself fully, and kick like a dolphin. Try to simulate a torpedo. Try crossing the pool with one breath, and once you can do that extend the distance. Another way you can practice endurance is by taking a breath and letting it out over six strokes (while freestyle swimming).

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

Competitive swimming

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, backstroke, breaststroke, and freestyle (frontcrawl). Also, there are different times to get to different levels in these strokes. These strokes can be swum individually or together in an individual medley.

Recreational swimming

The most common purpose for swimming is recreation. Recreational swimming is considered by many a good way to relax, while enjoying a good 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, 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 pools, where the water is calm. Therefore freestyle (which does not work as well in rough water) 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. 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 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. 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.

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

Ocean swimming

Ocean swimming is the sport of swimming and racing in the sea. Ocean swimming is popular in Australia, America and the Pacific Islands. Famous swims include the Alcatraz challenge which is a swim from Alcatraz island to the mainland.

Swimming for exercise

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 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 it is believed to reduce the harmful effects of stress.

Source : Wikipedia

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