Comment by cjcenizal

Amazing! This is about the dolphin kick performed on its side, rechristened “the fish kick.” I couldn’t fathom (ha) why the same kick rotated 90 degrees could be faster but it turns out that the kicking motion is constrained by the motion of the water around it. In the dolphin kick, the water moves up and down and is limited by the water’s surface and pool’s bottom. The swimmer frees themself of these constraints by turning on their side.