It is a misconception that the higher you are in the water, the faster you can swim. On the contrary, the highest speeds are reached by swimming completely submerged, because this allows for more efficient transfer of momentum to the water (which creates forward thrust according to Newton’s third law), and because less energy is wasted splashing water.
– Hans Starnberg, Department of Physics Gothenburg University Sweden
Turbulence at the surface of the water increases drag and slows swimmers down. Trained swimmers know that swimming underwater is faster than swimming at the surface.
In all the different types of competition stroke, from Olympic level down to club level and at all distances, the number of underwater strokes is strictly limited (especially at the turn) for this very reason. Competitors are disqualified and records annulled if they break the rules.
– Kevin Dixon-jackson, Eccles Lancashire
Hill Taylor stunned the crowd at a university event by completing the 50m backstroke in an astonishing 23.1 seconds – almost a second faster than the world record.