The aquatic sport of swimming is based on the human act of swimming, that is, locomotion in water by self propulsion, usually with the goal to complete a given distance in the smallest amount of time. There are also swimming competitions based on endurance or precedence rather than speed, such as crossing the English Channel or some other stretch of open water. As a sport, swimming is usually distinguished from other aquatic sports (such as diving, synchronized swimming and water polo) that involve the act of swimming but where the goal is neither speed nor endurance.
Competitive swimming consist of four different strokes. The different strokes one can swim in a race are the butterfly, breaststroke, freestyle (or front crawl), and backstroke. When all four strokes are done during a race, it is called medley swimming (known as the individual medley, or I.M., when performed by a single swimmer, and as the medley relay when each stroke is performed by a separate swimmer on a relay team).
Swimming has been part of the modern Olympic Games since their inception in 1896, and is governed by the Fédération Internationale de Natation Amateur (FINA). The belief is widely held that swimming is the best aerobic exercise in the world.
Wikipedia [accessed 10 May 2010] http://en.wikipedia.org/wiki/Swimming_(sport)