How important is the head position in swimming?

Take for example the picture below, which I’m sure many of you have seen. It is a photo taken from the bottom of the Beijing pool, and
it shows, on your left, Michael Phelps, on his way to his 7th gold medal, and on your right, Milorad Cavic of Serbia, on his way to a silver
medal in the 100m butterfly event.Had you not seen this race, however, you’d be tempted to tell me that I’ve mixed up my right and left. There is no way, surely, that Cavic,on your right, can lose this race. He has led for 99.5 m of a 100m race, and is centimetres from the wall. But Phelps touched first, by 1/100th of a second, in one of the moments of the Games.

It is against this backdrop, where gold and silver, history and anonymity are separated by millimetres, that sports sciences and the value
of attention to detail become apparent. If you look at Cavic on your right, you’ll see that as part of his early reach for the wall, he has begun
to hyperextend the neck, and the result is that his head is starting to rise out of the water. Phelps, on the other hand, has made a call to get
one last stroke in. His head is down, his arms are making one final sweep for the wall, and he is about to pip Cavic on the line.What this race comes down to then, is Cavic’s head position, which may have increased his drag (this is according to Phelps himself), and the timing of a lunge for the wall. Such are the margins between gold and silver. Phelps goes on to become the first man in history to win 8 gold medals at a Games, Cavic may never again be so close to an Olympic gold and a place in history as the man who denied Phelps the perfect Games.

Phelps - 100m fly @ Biejing 2008