Originally Posted by plee12
Thanks for your prompt reply.
Yes, I can understand what you're saying about the dolphin kick being different when used for backstroke starts.
However, I've come across many articles talking about how to improve the dolphin kick for butterfly where they suggest practicing dolphin kicking on your back and on your side.
For example, refer to the paragraph, "Position Kick Exercise" in this article:
This article seems to describe a body dolphin. I'm not sure what the value is supposed to be of doing it other than on your breast, and they don't explain it. Since the buoying up of your lungs is an inherent component of the body dolphin, I don't see the value of doing it on your side or back where that's not going to happen. You're going to be trying to practice an inherently different movement than the one you will be executing in butterfly.
Both of these are a dolphin kick - not the body dolphin that is central to butterfly. I think the purpose of doing it on the surface in the youtube video may actually be to give you feedback about whether you are doing it correctly, since your body should only be moving from your belly button down, and if the upper part of your body is moving, your head will be bobbing up and down, making it impossible to breathe part of the time.