information of swimmiming!!

actually,everytime you 換氣,you will be slower.so in the olympic swimmer,they only 換氣 2 or 3 times so they are more faster.

here are some information(hope that i can help you out!=]]])

The BUTTERFLY is the second fastest style after the front crawl, and is the fastest style regulated by FINA.
Breathing

Swimming the arms or the legs separately is difficult, and correct body movement is crucial for the arms and legs to use their full potential. The body moves in a wave-like fashion, controlled by the arm movement. As the hands go in, the hips go up, and the posterior breaks the water surface. During the push phase the head goes up and the hips are at their lowest position. In this style, the second pulse in the cycle is stronger than the first pulse, as the second pulse is more in flow with the body movement.
here are the informations of freestyle(hope that i can help you)
Breathing

Normally, the face is in the water during front crawl, with the waterline approximately at the height of the eyes. Yet, currently, many are debating whether the head should be kept down too. Breaths are taken through the mouth by turning the head to the side of a recovering arm at the beginning of the recovery, and breathing in the triangle between the upper arm, lower arm, and the waterline. The swimmer's forward movement will cause a bow wave with a trough in the water surface near the ears. After turning the head, a breath can be taken in this trough without the need to move the mouth above the average water surface. A thin film of water running down the head can be blown away just before the intake. The head is rotated back at the end of the recovery and points down and forward again when the recovered hand enters the water. The swimmer breathes out through mouth and nose until the next breath. Breathing out through the nose avoids water entering the nose.




hope that i can help you to swim faster!and of course to be the best answerer to this question!go to the two website for more info as i have the limited for words
參考資料:

http://en.wikipedia.org/wiki/Butterfly_stroke,http://en.wikipedia.org/wiki/Front_crawl

two web site for you:-
1) http://www.olympic.org/uk/sports/programme/index_uk.asp?SportCode=AQ
2) http://www.fina.org/swimming/index.php