From the occasional stroller to the most fanatical marathoner, walkers want to know: How far have I gone?
Bill McInnis, a former NASA engineer, has paid a lot of attention to people's obsession with measuring their athletic efforts, particularly when it comes to running and walking. For the past six years he has worked for Reebok International, the maker of sports and fitness gear based in Canton, Mass.
Next summer, Reebok is expected to unveil a new kind of sneaker that McInnis, who is the company's director of technology, says will accurately tell its wearers not only how far they have run or walked, but also what pace they set and how many calories they vanquished along the way. Called Smart Train, the high-tech shoes are expected to appear in July. Two versions will be available, priced at $110 and $250.
Most devices that measure a runner's distance are step counters. And even if they are properly calibrated to a runner's stride, as that stride changes - often a consequence of fatigue or changing terrain - translating steps into real distance becomes less reliable.
"When you are going over four to five miles, a 10 percent swing in accuracy either way really starts to add up," McInnis noted.
The key difference in the Smart Train shoes, which at first glance look like rather ordinary high-performance running sneakers, is a solid-state sensor called an accelerometer that measures the force exerted on the foot with each step. It is the same kind of device that in a car senses significantly sudden deceleration to trigger the release of air bags.
Using a special algorithm, a microprocessor in a unit in the shoe's tongue converts the stream of foot force data into how far and fast a runner is going.
"It's been an idea that's been a long time coming," said McInnis, who also directs product marketing and advanced research and development for Reebok. "It's just that the science and the circuitry has finally caught up to the point where you can make it small enough."
The Smart Train's components are small enough, in fact, to fit easily into the tongue of one of its shoes. A prototype of the device is no larger than the face of a quarter, only thicker, and is expected to run for months on watch batteries.
In the $110 version of the shoe, the wearer's information would be seen on a small LCD screen embedded in the shoe's tongue. In the higher-end model, called the Smart Train IQ, the unit is designed to communicate wirelessly, using radio frequency, to a wristwatch display.
Besides the time, day and date, the watch face can also display, in real time, distance, current pace, average pace and calories burned.
The wireless feature, something that has been incorporated for years into speedometers and odometers for bicycles, was a major advance in making the device appeal to runners and walkers, McInnis said. Without it, he said, "you would have to have a wire basically going up your leg."
The watch interface also makes expansion of features easier, McInnis said. "The beauty of the watch and RF communication is that the watch is just a receiver. You can plug in as many different items of data as you want."
Reebok is also considering adding to the shoes the ability to measure heart rate, McInnis said. Current heart rate measuring devices require people to wear a monitoring strap around their chest. Most people, McInnis said, don't like wearing the strap.
Though developers are working on measuring heart rates through a wristband, McInnis said it was not likely that heart rate information would be a feature of the first Smart Train line.
Right out of the box, McInnis said, the sneakers will be 94 percent to 95 percent accurate. To ensure accuracy rates near 98 percent, the shoes have a calibration step-up. Basically, the shoe can be trained to the wearer's running and walking strides and styles. McInnis said the wearer would need to run or walk only a quarter of a mile, the length of a common track.
"The device, because of the force involved and its measuring of that, knows whether you are walking or running," he said. "You could be a runner and a walker, too. Go out and do a workout and it will tally the whole thing up for you."
Smart Train's underlying technology was developed over the past two years by FitSense, a technology company in Newton, Mass.
Sam Joffe, president of the company, said FitSense and Reebok had been working together for the past year to create Smart Train. But the Reebok products will not be the first on the market to use what he calls the FitSense instant feedback technology.
In November, FitSense plans to release its own $200 version of the basic technology, without sneakers, Joffe said.
Called the FitSense FS-1, the system will include a 22-ounce, snap-on foot sensor, a wrist display and a wireless link to a personal computer. The PC link, Joffe explained, permits users to download their workout information into their computers, where it can be displayed, stored and charted.
Joffe said his company's technology had already been heavily tested - the FS-1 sensors have even been strapped onto the sneakers of track star Michael Johnson, who wore them in the Olympic trials in July, Joffe said.
McInnis said he did not expect this kind of measured feedback technology to be for everyone.
"If you go and watch the New York Marathon," he said, "the guys who are winning it - the Kenyans and all of those guys - they don't even need shoes. They are so efficient, they are just clicking along. In their head they know, 'Hey, I'm running a five-minute pace.' For the rest of us, we need a more supportive shoe."