Since I grew up swimming competitively, I suppose you can’t blame me for getting pretty fired up every 4 years when swimming gets world attention at the Summer Olympics.  And given my minor success in the 4×100 relay (Colorado Springs District champs, and 3rd @ Colorado State Championships that year), I probably can’t be blamed for nearly blowing a coronary when the U.S. Men’s 4×100 freestyle relay won the gold medal over heavily-favored France the other day.  You can watch the video here.  It’s worth watching not only because the U.S. wins, but to see how they win.  Aside from the otherworldly, can’t-believe-my-eyes comeback swim of the anchor, Jason Lezak, there is a technical reason they won as well:

In swimming, it is possible for one swimmer to draft off another just like you see in many other sports or when you’re driving behind a semi.  While drafting is probably most pronounced and used as strategy in the Tour d’ France, it plays a role in swimming.  The humongous French swimmer Alain Bernard – the recent world-record holder in the 100 free – anchored (swam last) the relay and was only expected to be beaten if the American anchor had about a 10 foot lead on him.  Instead, it was Bernard who entered the water in front the the American, and he had actually widened his lead by the half-way mark.

Strangely, in those last 50 meters, Bernard made what turned out to be a critical error, which was to drift from the center of his lane over to the left side, just next to his lane line.  On the other side of the line was the veteran American swimmer, who quickly noticed Bernard out of position and immediately moved over to virtually ride on top of lane line they shared, picking up speed in the Frenchman’s wake.  Drafting, when you watch it in action, seems like a miracle.  Mysterious invisible forces literally pull an athlete at speeds they never could achieve under their own power.  In this case, the drafting phenomenon was even more pronounced because Bernard is an absolute giant.  His shoulders are as wide as a desk.  While this gives him great power in the water, it also creates a sizable wake.  In those last 30 meters, suddenly one of the Frenchman’s greatest assets became a major weakness that the savvy American quickly exploited.

Nobody knows why Bernard rode his lane line for those last 50 meters.  Most likely he just lost track of his position in the pool, which is common (but a rare error in international competition).  Whatever the reason, his mistake helped Jason Lezak of the U.S. swim the fastest 100-meter split time in swimming history…by over 1 second. In all my years of swimming, sometimes covering 60-80 miles of water in a month, I never improved my 100-free time by over a second from one race to another.  Very few people have ever done something like that…without drugs, or good positioning in someone’s wake.

Olympic pools are designed to limit wake significantly.  Some have double-lines between the lanes, although I think they’re single at the Water Cube in China.  Still, the pool is one of the most technically-advanced on the planet.  If Bernard had been racing in the local community pool, my daughter could have jumped on his wake and probably have beaten him.  But even with the best low-wake technology in the world, nothing could control the big Frenchman’s giant wall of water.

As it turns out, nothing could stop the Americans either.