My foot lifted on its own. With just a slight motion as if to walk, I was stepping onto the uphill mountain path. A wearable robotic device strapped to my waist and legs detected and analyzed my movements, then added power to the next predicted motion. It felt as if my legs were moving automatically.
I put on Hypershell's HypershellX Ultra wearable robot, which uses artificial intelligence (AI) to match a user's movements and amplify and control force at the needed moment, and hiked Cheonggyesan.
Hikers started showing interest one by one from the moment I put on the device at the entrance before the climb. Some asked out of curiosity what it was, while an older hiker chided, saying, "Why wear something like that when you came to the mountain to exercise?" When asked if it really works, I finished gearing up, saying I was about to find out.
You wear the machine by buckling the section with the battery and motor around your waist like a belt and wrapping bands around both legs. Remembering a staffer's emphasis that the effect is maximized only when worn in the exact position, I paid attention as I put it on. I tightened the belt to fit snugly around the pelvis and waist, and fixed the leg bands 1–2 cm above the knees. It took about five minutes to power it on and sync it with the preinstalled app.
At 1.8 kg (excluding the battery), the weight was not a major burden. Because the battery sits at the back of the waist, it was difficult to wear a backpack. On the other hand, when sitting to rest or bending over, there was nothing in front of my abdomen, so wearing the device did not feel inconvenient.
Cheonggyesan is 4,000 meters from the entrance to the summit, with an elevation of 616 meters. I set off in Eco mode, which is lower intensity, then switched to Hyper mode after walking a bit. It wasn't a dramatic difference, but the assistive push became stronger.
Even though I fitted it as closely as possible to my legs, the sensation of the device lifting my legs felt awkward at first. Recalling that it takes time for the equipment to optimize to my movement pattern, I decided to let the machine take over for a while.
Past the midpoint, as the slope gradually steepened, I began to feel the effect bit by bit. It was especially helpful on stretches of continuous stairs, where the power transfer worked well enough that I sometimes bounded up several steps at once. Because the AI predicts a user's movements and boosts force, energy transfer seemed to be optimized more on evenly spaced stairs than on dirt trails.
Near the summit, when the pace of my companion with similar stamina began to slow, I was able to keep climbing without stopping at about the same speed as at the start by splitting the effort with the robot. I heard a delivery driver actually bought one, and it likely helped that person, too.
Near the top, the interest of tired hikers poured in. Questions started with "Does that really help?" and went on to price and how it works. When asked in return whether I intended to buy one, I sometimes shook my head.
It also helped on the descent. When I tried to speed up for a quick descent, I usually stressed my knees or ankles, but it felt like the robot absorbed that impact. Recognizing the downward motion, the power that had been lifting my legs was used to support my knees. To compare directly, I took off the device; my body felt instantly lighter, but my legs felt that much heavier, and the load on my knees felt much greater.
By the time I finished descending after about three hours, about two battery bars remained. Including walking and running on another day, it ran out after about six hours of use. You can swap in an extra battery, but that's something to consider for trekking where carrying spares is difficult. According to Hypershell, a single charge can cover up to 30 km.
Reactions around me to equipment providing convenience to humans were, unexpectedly, a mix of anticipation and reservation. A person surnamed Yoon, 35, who said they tried it at a pop-up store, said, "It seems like it would help in daily life, such as when lifting heavy loads, but the price in the 3 million won range is a burden," adding, "If the rental price is reasonable, I'd consider using it."
A person surnamed Song, 68, a climber I met that day, said, "It's a real mountain only when you're out of breath and your legs ache when you reach the top," adding, "I'm curious, but I don't think I'd bother using it."
A person surnamed Lee, 49, a colleague at the same workplace, went up and down five flights of stairs wearing the device and said, "It would be very useful if I got this for my father, whose muscle strength has weakened a lot. It definitely takes less effort," but added, "But if he wears this around, he won't get exercise and might lose more muscle, so I think more consideration is needed."