Boing!

Wouldn't it be neat if my shoes had springs? Every kid who's ever slipped on the high-tops, picked up the rock, and left it all on the court at the end of the fourth quarter has asked that question. It comes up during pregame warm-ups, postgame bus rides, and in sporting-goods stores all over the world. It is the natural by-product of millions of young athletes with endless amounts of imagination chasing stardom and glory in their chosen sport.

It's not a new question. Shelves at the U.S. Patent and Trademark Office groan with evidence of failed attempts to come up with a spring-loaded sneaker that a factory could actually make. People have been trying to do it for 100 years. And for the past 16 years, shoe designers at Nike Inc., a company with a history of brash behavior, seem to have taken it on as a personal challenge. By now, the results of their efforts have probably made their first public appearances on the medal stands in Sydney, and soon, they'll be in stores. They're called Nike Shox. And they really do have springs in them.

Shox couldn't be coming at a better time for Nike. The company has been in a prolonged slump, with flat sales in the United States and a stock price to match. While plenty of dusty attics are littered with the ghosts of shoe gadgets past (anyone remember the Reebok Pump?), many more bedroom closets have two or three newer pairs of shoes with packets of Nike Air in the soles. Air technology, which Nike introduced in 1979, changed the athletic-footwear business forever, and 20 years later, Nike is still selling billions of dollars' worth of Air-equipped shoes each year.

If history repeats itself, Shox has the potential to be a relatively quick fix to Nike's bottom line. But the technology behind it did not spring from the research lab at exactly the moment the company needed it most. In fact, it took nearly 16 years of fits and starts, teamwork, and brainpower to bring it to market. For a company that was started by and for track-and-field athletes, that pace may seem slow. But as Nike has matured into a company that cares more about the marathon than about the 100-meter dash, running the shoe-development process as a relay has turned out to be a good way to produce the kind of technology that has the potential to finish first.

On Your Mark: The Big Idea

Back in the late 1970s, a young professor of biology and applied mechanics at Harvard named Tom McMahon helped invent the tuned indoor track, which uses carefully calibrated layers of plywood and polyurethane in order to create a springiness that helps improve times and reduce injuries. Engineers at Nike caught wind of this development, and a few years later, they invited McMahon to spend part of his sabbatical at Nike trying to apply his new technology to athletic shoes. "They concocted this Frankenstein-looking aluminum boot," recalls Bruce Kilgore, 45, director of advanced research and development at Nike. "They'd change different springs in and out of it and run people on the treadmill, and from that they eventually arrived at a magical spring rate. They could tell that it had a very different feel because of the smiles that would break out on people's faces as they were running."

To Kilgore, who is an engineer by training, this was pure research and development, absent any pressure to produce a particular shoe with a particular design by a particular deadline. "We were thinking about creating a cushioning system that could have good vertical compliance and maintain some torsional stiffness that would help correct the stability issues we had," he says. Translation? "Even though the prototypes fell apart after five miles, there was some magic for people in putting that shoe on. That's what inspires you to keep going, failure after failure," says Kilgore.

McMahon returned to Harvard, and the Nike team eventually reached out to materials experts from the automotive industry in order to get rid of all of that aluminum. "We found a company that had worked on Formula One race cars," Kilgore recalls. "They wanted us to change the shoes to make the back half look like a big cantilever." (Picture a "V" turned on its side.) According to the mathematical model that had been worked up for Nike on a computer, the shoe could easily withstand the forces that runners would exert. "When we tried them out, they were very heavy," Kilgore says. "And when we walked in them, the heel bottomed out, and it hit the sole of the shoe before we even broke into a run."

At that point, Kilgore decided that he needed a break. He put the prototypes away, taking them out every so often just to keep his brain thinking about how to get them to behave like that original prototype sheathed in aluminum. During the next couple of years, he played around with the idea of putting piano hinges inside the shoes, but that approach didn't seem to solve the problem.