The idea of this is that it helps bring the legs up high in the water reducing drag but if you have a great body position from good stroke technique, or if you have a good buoyancy distribution for swimming (as most women do), then this is terrible advice. It offers no advantages and runs the risk of bringing you too high at the rear so you start to feel awkward and unbalanced in the water. You might also start to kick into clean air:
|Marina's been brought too high at the rear by having her head too low|
this is a common problem for female swimmers.
The irony is that very few elite pool or open water swimmers look straight down when they swim:
|Ian Thorpe using position 4|
|Michael Phelps using position 3|
|London 2012: Keri-Anne Payne (top) and Gold Medallist Eva Risztov using positions 2-3|
Whilst you're enjoying watching the Triathlon Grand Finals in London this weekend (they will be webcast here and on live BBC TV in the UK) take a look at the elite athletes in action in the water. You won't see the Brownlee brothers or Javier Gomez with their heads buried, they have a mid-range position which leaves them nicely balanced and allows them to see forwards a little underwater to try and pick up that all important draft.
For more information on head position in freestyle (and whether you should use a low head if you have sinky legs) see Choosing The Right Head Position For You.