Butterfly stroke
The butterfly swimming, and Butterfly is a swimming style. It was recognized by the World Swimming Federation in 1953 as the fourth official of swimming. The FINA was forced to take this step to make a clear differentiation from the traditional chest style.
History
Since the 1930s, the butterfly swimming had developed from the chest style. By Nachvornebringen of the arms over the water reduced innovative breaststroke their water resistance. Because of the increased force required by these swimmers swam usually only a few meters or a path in the butterfly style and then switched to the usual chest style. The butterfly swimming was economic only through the further refinement of the technique. When arm pull both arms at the same time with a slightly S-shaped pulling motion, the so-called keyhole draft, under water from front to back and then brought straight back over his head forward. It is usually breathed every two trains forward. The legs were originally moved in Grätschschlag, it later a full body wave movement developed ( undulation ), which continues from the rib cage down to the feet. Two leg strokes are performed per arm stroke. The second case is stronger than the first one.
The butterfly swimming is now after the crawl as the second fastest swimming stroke and after correctly performed chest style than the zweitanstrengendste. In competitions it is completed up to a distance of 200 meters.
With the introduction of the closed leg of swimming shock this was for decades known as dolphin - style, while looking at the butterfly style still understood the use of the sternum shock. The breaststroke kick is for several years no longer with the rules and the original swimming style is now obsolete. Due to international numbers into the float position is now called world's Butterfly and therefore called on German official butterfly.
Competition Rules
The rules determine the FINA that from the beginning of the first Armzuges after the start and after each turn, the body must be maintained in sternal recumbency and both shoulders lie with the water surface in a line. Leg strokes under water to the site are allowed. A movement of the legs in the horizontal plane ( sternum ) is not permitted. After the start and after each turn, a swimmer must perform several punches and a leg arm pull under water, which must bring him to the surface. The swimmer is permitted after the start and after each turn of up to 15 m to cover completely submerged. At this point, the head must have broken through the water surface. The swimmer must remain until the next turn or to your destination at the water surface.
Both arms need to be moved both backward and forward at the same time below or above water. All movements of the feet and legs need to be executed simultaneously; simultaneous upward and downward movements of the feet and legs in the vertical direction are allowed. The feet and legs do not need to be at the same level, but reciprocal movements ( Freestyle kicking ) are not allowed. A breaststroke kick movement is not allowed except in explicitly reported Masters competitions for swimmers with a minimum age of 20 years. At each turn and at the finish the swimmer must touch with both hands at the same time.