This New Treadmill Automatically Adjusts to Your Speed

A prototype developed at Ohio State makes indoor workouts more like outdoor runs by using sonar to detect where you are on the belt and keep pace

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Steven Devor, front, developed the automated treadmill using off-the-shelf parts, including an inexpensive sonar range finder and an existing treadmill. (Photo by Jo McCulty, Courtesy of Ohio State University)

Running on a treadmill may soon be less monotonous and a lot more like taking a run through the park.

Researchers at Ohio State University have developed a prototype treadmill that adjusts to your pace on the fly, no button presses necessary. Using an inexpensive sonar device pointed at the runner’s shoulder blades, the automated treadmill speeds up when the user moves forward on the belt, and slows down when he or she drifts toward the back.

The treadmill was developed by Steven T. Devor, associate professor of kinesiology at Ohio State, and Cory Scheadler, now an assistant professor at Northern Kentucky University. The two describe their work on the treadmill and its benefits to both training and research in detail in the latest issue of Medicine & Science in Sports & Exercise.

“One of the criticisms of exercise physiology research done in a lab with a treadmill,” Devor says, “is that running on a treadmill is nothing like running outside.” Testing in an environmental chamber—where heat, pressure and humidity can be adjusted—gets around some of these issues. But his primary aim was to develop a treadmill that mimics running and walking outdoors.

“We know that when you walk or run outside, you are constantly speeding up and slowing down,” says Devor, “and you don’t even recognize that it’s happening.” Looking for a way to allow a treadmill to adjust its speed naturally, he landed on sonar, which is well-developed and inexpensive. In fact, Devor says the sensor he uses costs less than $10.

While the automated treadmill is technically still a prototype, it’s built from off-the-shelf parts, including a standard treadmill that you might find in any gym, and a sonar range finder that can be picked up in DIY electronics stores, such as Radio Shack. The bulk of the work, lasting more than two years, involved interfacing the sonar data with the electronics that control the treadmill’s motor, and getting the speed adjustments to feel natural to the walker or runner.

“Initially it worked, but it wasn’t very smooth,” says Devor. “The key was getting the zones [on the belt that trigger speed changes] precise enough and small enough that you turn it on and you just start to walk, or break into a slow jog, or start sprinting.” He claims that the speed changes are now so smooth that it’s just like being outdoors, and even elite runners can get on the device and break into a fast sprint without hitting the front of the belt.

The automated treadmill is patent-pending, and, according to Devor, ready for a maker to license the technology and bring it to gyms and homes. Before that happens, though, some design work will likely have to be done in regards to the position of the sonar sensor. In the current version, the sensor is mounted on an arm behind the treadmill—for the sake of convenience, and to make it easily adjustable for people of different heights. But Devor admits that’s not ideal for a commercial product.

“The way things are in a gym, you’d want [the sonar sensor] up on the front panel,” says Devor. “The issue is, in order for it to be accurate, the signal from the sonar has to hit you in a precise location.” He says one possible solution would be to have the sensor on a sliding poll, so users could aim it at their sternum, regardless of their height.

The technology will likely see increased use in research labs and training facilities that test people’s aerobic capacities. These tests measure VO2 max, or the maximum volume of oxygen an athlete can use. The results are used to determine specific target heartrates for training.

In the researchers' study, involving 13 experienced endurance runners, the participants' VO2 max scores were 4 to 7 percent higher on the automated treadmill, versus on a standard treadmill, where time spent looking down to adjust speed seems to skew scores downward. With more accurate VO2 max scores, obtained on the automated treadmill, runners can make more effective training plans.

Considering just how competitive athletes—even amateurs—can be, a device that can give a measurable edge in training seems likely to land at your local gym eventually, especially considering that adding the necessary sonar and circuitry shouldn’t contribute greatly to the cost of new treadmills. 

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