Regan Penaluna in Nautilus:
Humans are land animals, and not natural swimmers. We have to learn how to swim, and it is up to us to find the fastest way to do so. The search may finally be coming to an end. In the last few decades, stroke mechanic experts have discovered that swimming under the surface is faster than swimming on the surface. “It’s hard to fathom that this could happen in track and field,” says Rick Madge, a swim coach and blogger. “Nobody is going to come up with a new way of running that is going to be faster than anything else. Yet we just did that in swimming.” And the fish kick may be the fastest subsurface form yet.