Need A Boost? Try An Exosuit
A tethered soft exosuit reduces the metabolic cost of running by 5% in a Wyss study funded by the DARPA Warrior Web program. Credit: The Wyss Institute at Harvard University
Imagine you’re out for a jog and you need a little extra oomph. Do you visualize a bear chasing you? Do you take a swig of your sports drink? Or do you turn your exosuit up to “high”?
Writing this week in the journal Science Robotics, researchers describe work on a “soft exosuit” that, in lab tests, could help a person expend about five percent less energy when running. Exosuit researcher Philippe Malcolm, one of the paper’s authors, says that wearable devices have the potential to improve human performance in more substantial ways than sweat-wicking fabric or bouncier shoes can. The researchers think that they can further enhance the energy-saving effects of their exosuit (which looks like a weightlifter’s belt combined with compression shorts), though they still need to make the device more accommodating and self-contained.
Philippe Malcolm is an assistant professor in the Department of Biomechanics and the Center for Research in Human Movement Variability at the University of Nebraska at Omaha.
IRA FLATOW: Imagine you’re out for a jog or you need a little extra oomph. Do you visualize a bear chasing you? Take a swig of some sports drink? Or do you just turn up your exosuit up to high?
Writing this week in the journal of Science Robotics, researchers describe work on a belt and shorts in their lab tests that could help a person use about 5% less energy when running. They think they can improve that number even more. Joining me to talk about that creation is Philippe Malcolm. He’s an assistant professor, Department of Biomechanics at the Center for Research and Human Movement Variability, University of Nebraska at Omaha. He joins me by Skype. Welcome to Science Friday.
PHILIPPE MALCOLM: Thank you, Ira.
IRA FLATOW: So I mentioned this word called an exosuit. What is an exosuit? Is that like the thing we see Iron Man wearing?
PHILIPPE MALCOLM: No, it’s actually quite different. Iron Man, he wears what we scientists call a rigid exoskeleton. So it’s composed of beams and rigid plates and joints. An exosuit is actually composed of functional apparel or textiles that anchor to different parts of the body, and then there are flexible cables that pull between these parts.
IRA FLATOW: So you have a big waist belt connected with cables to the shorts that go on the upper legs?
PHILIPPE MALCOLM: Yeah this version of the exosuit, indeed, it’s composed of the waist belt and two wraps that go around the thighs. And then there’s a cable that pulls between those two components and acts like a second pair of hip extension muscles that acts in parallel to your own hip extensor muscles. But the lab of Dr. Walsh at Harvard University is also working on different, other versions of the exosuit that assist with plantar flexion or other movements.
IRA FLATOW: So you’re giving– you’re sort of giving them an extra set of muscles without having to give them an extra set of muscles.
PHILIPPE MALCOLM: Yeah, that’s the underlying idea and could have a lot of different applications. One thing I also want to point out about this particular study is that it– we were able to reduce the energy cost of running, but it’s actually running on a treadmill, and motor deactivation units that drives the exosuit was actually stationary and positioned and next to the treadmill. So this is kind of a preliminary step in this type of research, but yeah.
IRA FLATOW: It can’t go very far when it’s hooked to the treadmill, can it?
PHILIPPE MALCOLM: No, but–
IRA FLATOW: You have to shrink this down and make it portable, right? If you’re going to–
PHILIPPE MALCOLM: Yeah, yeah, yeah. Yeah, definitely the engineers at the lab of Dr. Walsh are already planning and working on this. Also, if you look at the past, that earlier developments on exoskeletons and exosuits for walking, that’s also how those developments happened first. It’s done with what we call an off-board approach, so the actuation unit is next to a treadmill. That gives the advantage that it’s much more versatile, much more programmable, and that the person doesn’t have to carry the weight.
IRA FLATOW: Right.
PHILIPPE MALCOLM: And once we figure out which type of assistance is needed to assist the person, which appears to be quite difficult to find, then we can use that information for designing a portable device.
IRA FLATOW: Does it make them walk or run funny, so to speak? Any differently than your normal gait?
PHILIPPE MALCOLM: To the naked eye, you would probably not see a difference. Actually, there’s– on the page of the publication, there’s a video, and I think also on the Science Friday web page. However, we did measure some basic kinematics, the movements of the joints, basically. And we did see that with the assistance profile that produced the highest reduction in metabolic cost, we did see that it increased the extension a little bit. But it’s not visually perceivable.
IRA FLATOW: Mm-hmm. This is Science Friday from PRI, Public Radio International, talking with Philippe Malcolm at the University of Nebraska at Omaha. Now, you said 5% difference? Is that a meaningful difference?
PHILIPPE MALCOLM: Yeah, that’s a good question. I think before with exosuits, we were only capable to reduce the metabolic cost of walking. Just the fact of being able to reduce the metabolic cost of running is like a new benchmark and can lead to a lot of applications, maybe for recreational or injured athletes and such. Yeah, we’re not really sure if it’s perceivable.
I think if you would compare it– I saw on the website of Science Friday that there were comparisons to like footwear, with footwear, the reductions that are possible by reducing the waste are in the order of a few percent. So right now it’s still, I would say, comparable to having the best possible shoes. However, we’re sure that further improvements are possible simply because this was just very preliminary research.
IRA FLATOW: Is it possible that you could modify it or change it to be used in rehab? People who have had injuries need to get back– Would it be useful?
PHILIPPE MALCOLM: Yeah, definitely. And that’s definitely one of the applications that we’re thinking about. And that would already be practically possible using an off-board activation unit, because you wouldn’t need to leave the treadmill necessary. Yeah, and right now it’s optimized for reducing the metabolic energy costs of running, but it could be optimized for any other given objective, like, for example, reducing the strain in a particular muscle that’s injured would probably require some type of activation with a different magnitude and different timing. So yeah, that would definitely be an interesting future goal.
IRA FLATOW: Let me– well, one last question. I have about 30 seconds. Are there athletes now, like top class athletes, who run differently, like you’re making these people run on the treadmill? Are you copying something that’s already being done? But doing it better.
PHILIPPE MALCOLM: We’re not necessarily making the running movements itself more efficient. So if you would replicate the movement from the exosuit without the exosuit, that’s probably not going to help you.
IRA FLATOW: Uh-huh.
PHILIPPE MALCOLM: Instead, the goal of this research is to find the optimal assistance profile and movement profile for the human plus the exosuit. So that’s actually a different situation than the human–
IRA FLATOW: Gotcha.
PHILIPPE MALCOLM: –only running. It’s optimizing for the human plus the exosuit.
IRA FLATOW: All right, I got to run. I want to– so to speak. I want to thank you for taking time to be with us today. Philippe Malcolm, assistant professor at the University of Nebraska in Omaha.
One last thing before we go. It’s almost time for cephalopod week. Yeah, we at Science Friday have teamed up with Atlas Obscura for a series of cephalo parties in New York, LA, Chicago, San Francisco. For more information and to buy tickets, go to sciencefriday.com/movienight. That’s sciencefriday.com/movienight. It’s cephalopod week in New York, LA, Chicago, San Francisco. sciencefriday.com/movienight.
B.J. Leiderman composed our theme music. Our thanks to our production partners at the City University of New York. Have a great weekend. We’ll see you next week. I’m Ira Flatow in New York.