Walking, made 7% easier
Engineers have come up with a motor-free device to make walking more efficient and easier. It's something scientists once thought couldn't be done.
The prototype exoskeleton boot runs from just below the knee to the ankle. When you strap on a pair, you can reduce the energy it takes to walk by 7 percent. That means you won't burn as many calories.
It's wearable robotics without a motor or a power source. The device weighs one pound. It relies instead on a spring to store energy and release it with each step. It has a clutch that engages the spring at the proper moment.
The device is a little too bulky to fit under pant legs or socks.
"It doesn't look too bad. Looks kind of flashy," said Carnegie Mellon University engineering professor Steven Collins. He is the lead author of a study published in the journal Nature. "When you first put them on, it feels a little bit odd. Then after a few minutes you don't really notice it very much."
With an obese nation, making exercise burn fewer calories may not seem like the best idea. But it's not as crazy as it sounds, Collins said.
Studies show that when walking or biking becomes harder, people do it less. So maybe if it becomes easier, people will do it more. In the long run, they could burn more calories, Collins said.
This sort of hydraulic cast could also boost the development of other exoskeleton devices, perhaps for the hips. It could help disabled people walk better, Collins and other engineering professors said. The key innovation was coming up with the clutch, Collins said.
He said he has no plans to manufacture or market this particular device. But he will talk to others who want to do so.
This was more of an engineering challenge than a plan to create the next hot product, Collins said. For a long time, researchers had figured that evolution had already provided humans with the most efficient means of moving. So the question was: Can scientists improve on nature without using motors to cheat?
"Most studies show that human walking is incredibly efficient. So finding a way to make it better is incredibly interesting," said Andy Ruina at Cornell University. He is a biomechanical engineering professor. Ruina was not part of the study.
Ruina and other outside engineers praised the new device.
"It's totally cool," Ruina said in a telephone interview. He was walking and a little out of breath. "I wish I had those."
Critical thinking challenge: How might this energy-saving device make our country healthier?