Swimming rules

Swimming is divided into several different disciplines each with their own techniques and rules.

Freestyle is not actually a stroke but a choice of stroke for the athlete. However part of the body must remain above the water at all times, preventing underwater swimming.

To perform the backstroke a swimmer must swim on their backs with their faces up, although a certain amount of rotation is allowed as they swim. After the start or after a turn backstrokers are allowed to swim under the water for a maximum of 15 metres.

Breaststrokers must swim face down using a horizontal stroke with the arms and legs moving together. At the start and after a turn swimmers are allowed to make only one complete arm stroke and one leg kick while under water. On every other complete stroke the swimmer's head must break the surface of the water. At the end of the race, and at each turn, the swimmer must touch the end of the pool with both hands.

The butterfly stroke evolved from a loophole in the rules of the breaststroke. It is similar in many ways, except that the arm stroke and leg kick are made on a vertical plain rather than a horizontal one. As with breaststroke, butterfly swimmers must swim face down and on the surface of the water apart from after the start and after each turn when they may travel underwater for up to 15 metres. They also must touch the end of the pool with both hands at each turn and at the finish.