Swimming is one of the world's oldest forms of competitive sport. Swimming ability was valued in a number of ancient cultures, including Greece and Japan.

As swimming became established as a sporting activity in the early 1800s in Europe, the most common type of swim stroke employed was a variation of the breaststroke, where the swimmer used both arms below the water and the head positioned above water. In 1844 at a competition held in London, a number of Native American entrants from the United States used a stroke that was similar in style to the modern front crawl, where the swimmer's head was submerged from time to time and the arms directed in a windmill motion. Although superior to the breast stroke, the Europeans saw the innovation as undignified and did not adopt it at that time. The first successful attempt to swim the English Channel, a distance of 21 mi (32 km) occurred in 1875.

Swimming pools were built in London, and in other European cities, prior to 1900 and the first European swimming championships were held in Vienna in 1889. Swimming was included as a sport in the first modern Olympic Games in 1896 as a men's sport; the first women's Olympic swimming was contested in 1912. The most famous of swimming strokes was developed in the early years of the twentieth century by Australian Frederick Cavill (1839–1927), who adapted the Native American overhand swim stroke and added a flutter kick (a repetitive kicking motion). This stroke was known as the Australian crawl; it is now designated in international swim rules as the crawl, the stroke used in freestyle swimming events.

Swimming has produced some athletes who became the subject of international recognition. American Johnny Weissmuller (1904–1984) won a total of five Olympic medals in the 1924 and 1928 Summer Games. Weissmuller parlayed his swim fame into a Hollywood movie career as "Tarzan." American Mark Spitz won seven gold medals in the 1972 Olympics. Australian Ian Thorpe, the 6 ft 7 in (1.98 m) "Thorpedo," won a total of nine medals in the 2000 and 2004 Olympics, the most ever by an Australian athlete. Yona Klochvova of the Ukraine won successive gold medals in the 2000 and 2004 Olympics, in addition to being named the world's top 400-m medley swimmer for seven successive years.

The Federation Internationale de Natation de Amateur (FINA), was founded in 1908. FINA is one of the widest ranging of the international governing bodies in sport, as it is the authority in the distinct disciplines of swimming (races up to 10,000 m staged in swimming pools), water polo, open water swimming, diving, and synchronized swimming. The global popularity of swimming is illustrated by the fact that over 200 national swimming associations comprise the FINA membership. Swimming is the most popular of the sports directed by FINA; there are state, regional, intercollegiate, national, and international swimming competitions, in a number of different formats and age groups, available in every region of the world in a given calendar year.

Swimming competitions are held in one of two settings sanctioned by FINA. A short course is a swimming pool 25 m in length; a long course is a 50-m pool. The 50-m facility is the standard distance for international and Olympic competition. The pool is divided into lanes, typically eight in total, with each lane divided by floating markers extending the length of the pool; to assist the swimmers in maintaining their orientation and to permit them to swim in as straight a line as is possible, the center line beneath each lane is marked along the bottom of the pool. In North America and Europe, most competitive swimming competitions are held in indoor facilities; in countries such as Australia, a world power in the sport, the climate permits the extensive use of outdoor swimming pools.

Swimming races range in length from the 50-m sprint (one length of the pool in Olympic competition) to 10,000-m events. The physiological demands of swimming are similar to those of running, in the sense that a 50-m sprint specialist will not likely succeed in a long distance race, and the various distances and specialized strokes demand specialized training approaches. There are four general types of swimming races, each defined by the stroke that the swimmer is required to employ-, freestyle (where all swimmers use the crawl), the breaststroke, the backstroke, and the butterfly. One event, the individual medley, requires the swimmer to use each of the four stroke types for a designated portion of the course. There are also relay races at various distances, including the medley relay where the four team members use a different stroke in their successive relay legs.

All types of swim strokes have five general components: the arm stroke, the kick, the timing and coordination of the body movements, the body position relative to the surface of the water, and the breathing rhythm. All swim performance theory is predicated on the fact that the human body and its composition (over 90% water), is only slightly less buoyant that the substance in which the athlete is racing.

A swim race has three distinct components, the start, the swim, and the turns. Each aspect has its own distinct technique, founded upon a body of practical racing results and scientific research as to the most efficient methods to move through and over water.

Swimmers are permitted to wear a variety of different styles of swim suits during competition. For many years, the standard was a tight fitting suit that exposed most of the body to the water; the tighter the fit, the less likely air bubbles would become trapped between the skin and the suit, causing a less sleek profile in the water. Swimmers would remove all body hair, to reduce the resistance of the water upon their skin, including the wearing of a tight race cap and hydronamically contoured swim goggles. There have been several advances in swim suit technology. One notable example was the development of the Speedo "Fastskin," a material modeled to a significant degree after the skin characteristics of sharks. The swim suit material, like the shark skin, has a series of dermal denticles, which form a series of V shaped ridges across the surface. The denticles reduce the drag that otherwise occurs from the passage of any object under water, by creating a series of tiny deflection points that force the water to pass more readily over the suit surface. These suits are often worn as a full body device, with the arms and feet uncovered.

Freestyle swimming is the fastest form of competitive swimming, as the combined function of the arms moving in an over hand and a constant kick keep the body on a relatively even and efficient plane as it moves through the water. By rule, the swimmer may only remain under water for 15 m (50 ft) at the start and at each turn; otherwise the swimmer must be on top of the surface.

The breaststroke is a swimming stroke performed with the swimmer facing downward on the water. The swimmer's shoulders must remain in line with the water at all times. With their head above the surface, the swimmer extends their arms directly ahead, with the palms facing outwards, making a sweeping stroke with both arms remaining underwater at all times. On the repeat of the stroke, the arms are permitted, by FINA rule, to break the surface of the water. The swimmer performs a "frog kick," where the legs are brought towards the torso, and then extended outwards underwater. The swimmer's arms and legs must move in unison; flutter kicks, dolphin kicks, and scissor kicks are prohibited, as are flip ("tumble") turns.

The butterfly evolved as a swim form from the breaststroke, when swimmers brought their hands and arms out of the water to drive themselves forward. The butterfly, as the name suggests, is executed by a sweeping motion of the arms above the water, accompanied by a dolphin kick. The swimmer is face down on the water, coordinating breath with

Australian Giaan Rooney in the women's 50-m backstroke at the 2005 FINA World Cup.
the arm strokes. The butterfly is a very physically taxing event. The swimmer is permitted to be underwater for 15 m at each turn and at the start.

The backstroke is performed with the swimmer's head and stomach facing upward in the water. The stroke is an alternating windmill type motion with each arm, as the swimmer drives their body forward with a flutter kick.

Swimming is a sport that requires the athlete to develop total fitness-cardiovascular endurance, muscle strength, flexibility, and power. A schematic analysis of a typical swim race illustrates why each of these fitness elements is important. The race start requires an explosive entry into the water, employing a measure of body control and finesse to enter the water at an optimal angle for efficient movement. A powerful leg drive at the start will translate into significant benefits for the racer; if the start takes the swimmer either too deep into the water, or so shallow that additional water resistance is create by their body on entry, the benefits of a powerful start are lost.

As the swimmers move in their lanes, they seek a stable and efficient position. In shorter races (200 m and under), the demands placed upon the body's energy systems are primarily anaerobic; in the longer races, the body utilizes its aerobic systems, with anaerobic capability needed at the swimmer's drive to the finish.

On the approach to the opposite wall to make the turn, the swimmers will seek to maintain their speed by timing the execution of the turn. Each swim discipline has specific rules about the type of turn that may be employed (either open, where the swimmer changes direction at the wall, or a flip turn, where the swimmer executes a somersault and uses the wall to obtain a push in the opposite direction). Similarly, there are limits as to how long a swimmer may remain underwater after executing a flip turn; it is a general principle of swim mechanics that the body tends to move most efficiently under water as opposed to on the surface.

Swimming is a sport where the body's entire musculoskeletal system is engaged. For this reason, swim training is directed to the building and maintenance of all muscle groups. Swimming presents a lower risk of musculoskeletal injury than many sports; the chief causes of injury are related to

Competitors at the men's 25-m open water event at the 2005 FINA World Championships in Montreal, Canada.
training, and the repetitive nature of the swim strokes which may lead to a variety of over use syndromes. Shoulder injuries, particularly those in relation to the function of the rotator cuff (the small four muscle and tendon structure positioned at the top of the shoulder, the tissues that control the amount of rotation possible in the joint), are relatively common.

The nature of swimming and the timing of the competitive swim schedule for any athlete make the development of a periodized training schedule a priority for a swimmer. As with a competitive runner, there will be readily identifiable events in the year that will be of greater importance to the athlete. It is these events that should be identified as ones for which the athlete will "peak," with training intensity adjusted accordingly. Dry land training particularly focused stretching programs to enhance optimal range of motion in the joints, weight training, and plyometric work to build explosive leg drive in both kicks and starts, will be components of this aspect of training.

The generally low incidence of injury, and the popularity of swimming generally has fostered a vibrant international master's competitive swimming community. Master's swimming is sanctioned by FINA, and master's competitive events, commencing at age 35 for both men and women, are staged throughout the world.

SEE ALSO Diving; Swimming strength training and exercises; Synchronized swimming; Triathlon.