Running to success: The tracks of the 'Bird's Nest' National Stadium are reflected in a spectator's sunglasses during the 2008 Olympic games.
Credit: AFP
Tuned surface
Their results were complex, but what they found was that there is indeed a perfect springiness for track surfaces. Too much cushion in the track and it eats energy, just as described by Grimes. Too little, and you bounce off too fast, without giving the body's natural springs – those muscles, tendons, and ligaments – time to store and release the ideal amount of their own energy.
Armed with that information, McMahon and colleague Peter R. Greene designed a new "tuned" surface for Harvard University's Gordon Indoor Track and tennis facility, calculating that it should speed up runners by two to three per cent compared to the firmer surface they'd been used to.
The new tuned track was 220 yards (201 m) of wood topped by polyurethane. It worked. In its first season of use, from 1977 to 1978, McMahon compared how Harvard's runners fared on it, vs. the tracks they used for meets at Princeton and Cornell Universities.
He found that, even though away meets are championships where the Harvard runners should have been trying for peak form, the Harvard runners were 2.91 per cent faster at home. It wasn't just a home-field advantage. Runners from other schools were also faster at Harvard.
Since tuned wood tracks aren't weather resistant, there's been no big rush to build them outdoors, even if they did meet IAAF standards. But Harvard's and similar indoor facilities that McMahon helped design are still in use and show just how much difference a running surface can make.
When McMahon did his research, he predicted that a tuned surface for an outdoor track could improve performance times there by as much as they did indoors: about 3 per cent, or 7 seconds.
Record beating
By that time, races were being run on synthetic tracks, which first came into use in the early 1960s. Much better than the sometimes-muddy dirt and cinder tracks used in Bannister's era, these tracks had probably contributed substantially to the improvement of the one-mile record, then standing at 3 minutes 49.4 seconds, set by John Walker of New Zealand.
Today, the record is down to 3 minutes 43.13 seconds, set in 1999 by Hicham El Guerrou of Morocco. Racing fans blame much of that improvement on improvements in running shoes and training methods. But track manufacturers are perfectly aware of McMahon's work. Like Grimes, they're fully aware of the fine line between a track that's too firm and one that's too hard, and are always looking for the optimum performance zones within the limits set by the IAAF standards.
So as you watch the runners circle the Bird's Nest track in Beijing, realize that the lowly surface beneath their feet is part of what makes them fly.
Richard A. Lovett is a writer, and dedicated runner, based in Portland, Oregon. He is also a regular contributor to Cosmos.
