Michael Phelps will no longer display his Fu Manchu style when he does the first for-real dive into the Water Cube pool today.
Excess body hair, in any part of the body, would make the decisive difference, were it just a tiny fraction of a second. That’s exactly what counts - especially if you happen to belong to the crème de la crème of swimming.
It doesn't matter whether you wear a hi-tech body suit or a minimal Speedo. All hair must go, covering it with a piece of cloth is not enough. The only exception would be the top of your head, most of the time be above the surface anyway and covered with a thick and tight cap. Many elite swimmers even shave their heads - and still wear a swimming cap to penetrate the water as smoothly as possible.
A lot of swimmers prefer to let their body hair grow until the last moments before a major competition. That has both physical and psychological advantages. You get rid of that little extra resistance that still benefits you when training - and on the other hand you feel that after the shave you are able and obliged to do a little bit better than you did the day before. And, as believers say, shaving also increases the “feel for water” - something that I guess the modern body suits definitely won't do.
Like it or not, even Alain Bernard will spend a few moments to liberate that perky shark of his from the jungle and let it swim free of any unnecessary obstacles.