Who’s the World’s Fastest Runner?

Justin Wolfers’s excellent post on Usain Bolt‘s extraordinary 200-meter race mentions in passing that “it is only a fairly recent phenomenon that the 200-meter typically yields a faster average speed than the 100-meter sprint.” We’re living in a topsy-turvy world where the world-record pace is faster on a longer distance than a shorter distance.

When Bolt set a new world record in the 100-meter race last May, lots of people declared him to be the “World’s Fastest Man.” But to my mind, he didn’t legitimately take that title — neither then nor last Saturday when he lowered his own 100-meter record to 9.69 seconds at the Olympics.

Even after Bolt’s Olympic 100-meter, Michael Johnson had a strong claim to be the world’s fastest.

One of the amazing things about Johnson’s 1996 world record in the 200 meters is that his pace or average speed for the 200-meter record was faster than the average speed for the fastest 100 meters. Johnson, covering twice the distance and running the curve, was able to sustain an average speed of 9.66 seconds per 100 meters. At the time, Donovan Bailey‘s world record in the 100 meters was 9.84 seconds.

So to my mind, Michael Johnson became the world’s fast human in 1996. His act made it clear that the difficulty of having to accelerate from zero in the first 100 meters could outweigh the disadvantages of additional distance and the curve. (This cool graphic shows that Michael Johnson wasn’t the first 200-meter record holder to have a faster pace than the 100-meter record; Tommie Smith pulled off a similar feat in the 1960’s.)

The world record in the 100-meter race has been lowered or matched eight times since 1996 (including times that have been later voided for doping), but no one in the 100-meter — including Usain Bolt with his current 9.69 record — has ever run at a lower average speed than Johnson’s 1996 record.

Bolt’s 200-meter record earlier this week is important because he can now truly claim to be the world’s fasted human — averaging 9.65 second per 100 meters.

Now that Johnson and Bolt have overturned the simple notion that average speed declines with distance, it becomes slightly harder to figure out what distance race in track would maximize average speed. Would it be 10 meters, 50 meters, 150 meters, or 300 meters?

It’s also far from clear whether Bolt’s new average speed record will stand. Bolt ran 9.69 seconds in the 100-meter race without giving his full effort for the last 20 meters. He might be able to run 100 meters at an average speed that is faster than his own 200-meter average speed. Bolt may not have many other close rivals, but the lens of average speed gives him a new way to compete against himself.