I read in the Wall St Journal article that Terry or some use a frog kick with their butterfly. I swam breast stroke in college (42 yrs ago) and never could do the dolphin, only the frog (or whip as we called it then). In fact had no distance durability in free either, breast stroke was it for me. Does anyone know if those using it are using a one kick to one stroke or a double beat like the dolphin? Haven't been swimming much for workout in decades, bike, run, ski. But the Fly article has me intrigued. If you haven't read it:
http://online.wsj.com/article/SB1000...396369848.html