SW 8 BUTTERFLY
SW 8.1 From the beginning of the first arm stroke after the start and each turn, the body shall be kept on the breast. Under water kicking on the side is allowed. It is not permitted to roll onto the back at any time.
SW 8.2 Both arms shall be brought forward together over the water and brought backward simultaneously through-out the race, subject to SW 8.5.
SW 8.3 All up and down movements of the legs must be simultaneous. The legs or the feet need not be on the same level, but they shall not alternate in relation to each other. A breaststroke kicking movement is not permitted.
SW 8.4 At each turn and at the finish of the race, the touch shall be made with both hands simultaneously, at, above or below the water surface.
SW 8.5 At the start and at turns, a swimmer is permitted one or more leg kicks and one arm pull under the water, which must bring him to the surface. It shall be permissible for a swimmer to be completely submerged for a distance of not more than 15 metres after the start and after each turn. By that point, the head must have broken the surface. The swimmer must remain on the surface until the next turn or finish.