It’s roughly 90 degrees with 90% humidity, the sort of Midwestern summer day that turns the cornfields into a jungle. I’ve just climbed up and down nearly 1,000 stairs at a local park, and yet, I’m barely sweating.
I wish I could tell you that I’m just in great shape, that I don’t have a bum knee, that I am a person who glistens rather than drips. But in fact, I’m cheating. I’m wearing a pair of robo pants that are erasing half the effort.
Called MO/GO (short for mountain goat), it may very well be the world’s most accessible exoskeleton when it goes on sale later this year for $4,500. Created by the startup Skip—a mobility company that spun out of Google’s moonshot “X” division—in partnership with the outdoor gear company Arc’teryx, MO/GO is one-part robot, one part technical pants. Its creators call it an “ebike for hiking,” and it’s hard to come up with a better metaphor. MO/GO lets you hike farther, with more ease—there’s just no bike in the way.
While exoskeletons have been a sci-fi idea for decades, we’re in a sweet spot of technologies (ranging from motors to batteries to AI) that’s making their practical application feasible. In 2022, exoskeletons represented a $2 billion market, focused mostly on military and rehabilitation. But by 2031, that figure could reach $23 billion, as options come to market and the U.S. in particular experiences an influx of adults over 65 who want to stay active.
The origins of Skip at Google X
Skip started out as generalized research into the future of mobility at Google X. Nearly 40% of people over 65 live with a disability, and the team was considering how aging people, in particular, could keep moving to maintain their health and independence. By 2020, that project had become Smarty Pants, a soft robotics system that could use sensors and power to help someone walk. Google X then teamed up with Arc’teryx in a slow burn project to bring the idea to market.
“I specifically knew we were going to want a partner that could do the design, wearability, usability . . . most of our team is roboticists,” says Skip cofounder, Kathryn Zealand.
The team made a lot of progress at Google. They experimented with different joints, pneumatics and soft actuating technologies, and algorithms before developing an electric motor that was half the weight of anything off the shelf. But as Google reorganized into Alphabet, and generative AI put Google’s money-printing machine that is Search into question, Zealand notes that low-risk software projects started to edge out costly hardware projects as a company priority.
“Google was an amazing place to start the project because we had an interdisciplinary team,” says Zealand. “But at some point in time it stops being an accelerant, and starts being a lot of management and overhead.”
So alongside her cofounder and lead designer Anna Roumiantseva, Zealand recruited half of Skip’s team out of Google and accelerated the partnership with Arc’teryx to release a commercial product that could realize some early potential of the technology, even if it wasn’t ready to help the most mobility challenged.
“We heard a lot from people who felt self-conscious, who didn’t want a brace or walking stick but loved hiking poles and things that looked like [outdoor] gear,” says Zealand. “Even if one day we want to [help] everyone from movement challenges, can we start with a motivated user group of people who used to be hikers and runners?”
The result of that early idea is MO/GO, an exoskeleton integrated into a pair of pants that weighs a mere seven pounds with all components included. (For comparison, a traditional hiking boot can weigh two pounds alone). “For me the differentiating factor is taking it out of the realm of exoskeletons, which look and feel like an Iron Man suit and cost tens of thousands [dollars], and to make it approachable for an everyday person,” says Roumiantseva.
Designing the hardware
The MO/GO’s core robot engine is small and light in your hand, something like a carbon fiber boomerang. It sits just outside of your shin, knee, and thigh like a second leg. It’s hard to believe that this little machine can do so much. But the knee joint of the exoskeleton is the one of the lightest magnetic actuators in the world—an electric motor not so different from that in a Tesla.
The magic is a bit more believable once you step into the full setup—which involves two bracers you strap onto each leg. These bracers connect the robot to your legs, and the pants sit in between these two layers like the filling of a sandwich. The bracers zip right into pants designed by Arc’teryx. The tailoring and integration between Skip’s electronics and Arc’teryx’s performance fabrics is refined. Even without zipping them in, the bracers remained anchored in the pants, stably hanging from performance gossamers. They cause the pants to balloon out when you look at them, almost like a crinoline dress on your legs. (Seeing photos of myself wearing MO/GO later, I’m actually surprised how subtle it looks on my body, because the sensation of wearing the bracers is comfortable, but by no means subtle.)
To hook MO/GO onto the pants and bracers, you simply slide and click it onto connection points that poke through ports near your shin and quad. To adjust the fit, you can twist six knobs to tighten or loosen the bracers onto your skin—a softer experience than it could have been thanks to Arc’teryx’s textiles, foams, and cinching mechanisms. Integrated wires snake to a battery fanny pack that fits into the back waistline of the pants. That battery will be in the final release, but the wiring will be eliminated by the commercial version.
Turning MO/GO on involves holding the on button for two seconds. Once booted, the lights go blue. To ramp up or turn down assistance, you hit an up or down button on your knee. And that’s it. Everything else is automatic. Skip uses sensor algorithms to identify when you’re walking or climbing and respond with the proper motion. Over time, it can supposedly even learn your gait so it feels more natural.
What it feels like to walk with an exoskeleton
Using the MO/GO was entirely different from what I expected an exoskeleton to feel like. While the motor lives at your knee, you don’t feel anything in particular there. Rather, climbing up the stairs, it felt like a little bar shoved from below my upper hamstrings, just between my knee and glutes. (To create this leverage, MO/GO anchors to my ankle, and so it felt almost like someone was stepping on the back of my heel.)
After a few dozen uneasy steps, I put faith into the machine, and was bounding up the stairs two at a time. I found larger steps to be easier than smaller ones, and that it was downright luxurious to be a little reckless on the staircase with no punishing pressure on my knees.
Going down the stairs was an entirely different sensation. It felt like MO/GO locked my knee in place with each downstep, so that when I landed it could absorb the shock—almost like my leg was lifted by its own little chair. There was no spring or bounce. Just support.
All of this said, I wouldn’t describe the sensation as natural, and moving didn’t exactly feel mindless. You can see just how hard I’m concentrating in the video from my testing. During my 45 minutes or so with MO/GO, my brain was still adjusting to the micro delays of my footfalls, and I never for a moment forgot that I was wearing a pair of robot legs. (It doesn’t help that each step is accompanied by a loud robotic whir straight out of a sci-fi movie; reducing that noise is a priority for launch.)
What’s most trippy is just walking around. MO/GO kicks your knee forward with each step, almost like a doctor testing your reflexes with a mallet. It was a bit too eager, perhaps, but that didn’t bother me. The only unsettling thing that I experienced was that, for whatever reason, MO/GO would sometimes kick out my left leg against my will when climbing the stairs. I never lost my balance because of this—and I’m told onboard machine learning would automatically master my personal gate over time—but it did remind me why this technology probably makes more sense being tested with an able-bodied, outdoorsy crowd first before making its way to the more obvious use cases of accessibility and universal mobility.
“The assistance comes in like just a little earlier than you want it or just a little later,” says Roumiantseva of the delays the company is currently working to eliminate. “You’re never going to fall . . . but it does undermine your trust.”
Getting the feel right is largely the challenge in refining MO/GO into the future—just how much does it help, and how fast? “If you’re optimizing for maximal metabolic efficiency, you get sudden push, whereas people prefer a more gentle lift,” says Roumiantseva. Indeed, aside from those moments I was being overtly puppetted, the most mind-bending part of the experience was that I often couldn’t tell how much MO/GO was helping me at all. Was it moving me, or was I moving it?
It wasn’t until I turned off the MO/GO that I could quantify how much this system was assisting me—which was quite a bit! It was as if my robot self went to sleep and my fleshy muscles woke back up. The system can currently offset about half the effort of hiking, and as the company fine-tunes its movement algorithms, Skip believes it can offset another 30% of that effort by launch.
In real world terms, I was able to climb and descend the staircase three times in a row. I sweated a bit, because I was in a hot environment. But I was never completely out of breath, and my heart rate wasn’t notably elevated when I was done. For the shape I’m currently in (bad!), that’s pretty astounding.
The future of exoskeletons
You might wonder, could you get addicted to this feeling? Could wearing MO/GO be so lazily automatic that you wouldn’t want to walk on your own anymore? For now, no. When I removed MO/GO, I felt like my body stepped out of a 4×4 and into a sports car. Granted, my sports car may be a 1980s vintage and only have a four-cylinder engine inside. It may not love steep grades like that truck. But it’s still comparatively nimble and a joy to move. It was nice to get all of me back.
Skip and Arc’teryx are earnest about what they’ve built, and seem confident about what it can be. Right now, Roumiantseva says they need lots of movement data so that MO/GO can understand natural footfalls—not just for its own developers and their friends who have trained the system, but for everyone. That’s why Skip will enter a public beta later this year before launch where people can test MO/GO during a climbing clinic.
But for others, I suspect the system will feel like a lot to don and doff. Four hands assisted me getting set up with the bracers and pants, which took a few minutes. Hikers and mountain climbers will be used to these sorts of technical equipment demands in a way the average consumer may not be.
In the not-so-distant future, Cam Stuart, who works in Advanced Concepts at Arc’teryx, says that the hardware can be more integrated with the pants. Perhaps you slip them on, and a single button or dial can lock down all the bracers to the correct tightness. Furthermore, the team is considering how this technology could fit into other outdoor sports, perhaps more naturally than hiking. The clearest potential? Skiing and snowboarding. Squatting for these sports can be exhausting, but MO/GO could absorb the load—and hook right to someone’s bulky ski boot instead of their leg.
“We felt that hiking was an achievable thing. It’s something that a lot of people do and can really wrap their heads around,” says Stuart. “But absolutely, there are so many outdoor opportunities.”
MO/GO is available for preorder today. And no doubt, that purchase is something of a leap of faith. Both Skip and Arc’teryx readily admit that the product is a work-in-progress that’s still being refined for commercial release. Whether you love or hate the product comes down, not just to the sensation of wearing nylon, lithium, and carbon fiber, but of wearing an AI that’s literally in control of your body.
My own experience, while incredible, was still a few steps short of what you’d want in a consumer product. However, after only an hour living with robotic legs, I have zero doubt that mini exoskeletons like MO/GO will soon be an essential part of our lives—especially for those who have difficulty walking. I’ve tried out gee-whiz technologies for nearly 20 years, and for all of the promises of gadgets to make us more creative, more productive, and more amused, it’s hard to think of a more enticing premise than being stronger and always able to move.