Andrew Georgitsis, on the Intro to Tech DVD, says it is primarily the SIDE of the fin that delivers the power. As far as I can tell, from the times I can actually get it to work, the keys are: Extend the fins slowly and carefully in the position they would be in at the end of a good frog kick (bottoms apposed). Then sweep them outward, catching the water on the side and a little bit of the "top" of the fin.
I do have to say that, although I no longer drop my knees when doing this, I still gradually go butt up as I continue to kick. Not sure why. Joe Talavera says keep one's head up and that will stop it, but I had my head PINNED to my first stage today (and the neckache to prove it) and STILL went up.
I do have to say that, although I no longer drop my knees when doing this, I still gradually go butt up as I continue to kick. Not sure why. Joe Talavera says keep one's head up and that will stop it, but I had my head PINNED to my first stage today (and the neckache to prove it) and STILL went up.