The physics of undulatory human swimming
(PHYSorg.com Physics)

A research team led by the University of Tsukuba created the most complete recording to date of a human swimming underwater like an eel or lamprey. Using motion-capture equipment and particle velocity monitors, the scientists were able to study this `undulatory` underwater propulsion and the nearby water flows it created. They found that jets produced by coalescing vortices help explain the efficiency of this swimming method, which might be applied to novel propulsion systems.