The Butterfly Kick

The "Dolphin Kick" is part of the butterfly swimming style. Although it has the word kick in it, the kick involves motion through the whole body of the swimmer. It consists of creating a fluid-like wave motion that begins in the swimmers chest and it increases in amplitude as it reaches the toes. It is important to keep the legs moving together at all times. ¿Did you know Michael Phelps can do two simultaneous waves instead of one?

Although the water gives more resistance than air, the fact that the whole process happens underwater reduces the resistance of moving body parts from air to water and the other way around, that makes this kick the fastest.

This kick requires a lot of flexibility in the whole body, specially the ankles; using fluid dyamincs some engineers at George Wahington University came to the conclusion that 75% of the force created by the kick comes from the last fast extending movement the ankle makes. This is key to the machine dseing as is need to emphasize the ankle's movement.

We are sharing this video we found at Youtube where the swimmer demonstrates the syle slowly for your appreciation.

And lastly this other video from PopSci Magazine of the Finit Element Analysis of a dolphin kick, where the ankle's importance is demonstrated. (We hope we learn someday what finit element analysis is, but still we can understand forces are larger at some points in space and time.)

We will be showing our first prototype as soon as it's ready (Although it will roughly imitate the looks of the style.)

Erick & Luis

Source: How it Works: The Dolphin Kick. Popular Science Magazine. http://www.popsci.com/how-it-works/article/2008-08/how-it-works-dolphin-kick