This isn't new. At all. And they even say so in the article - what a terrible title. This has always been the fastest and best way to kick when underwater when

This isn't new. At all. And they even say so in the article - what a terrible title. This has always been the fastest and best way to kick when underwater when appropriate for the stroke (In this case - anything but breaststroke, and ensuring you're not completely on your side if doing it during backstroke.) There's a reason why there are markers on the lanes for how far you can go underwater - otherwise swimmers would be underwater all the way until the next wall.