It's not about pushing past your limits every single time, but about finding your own rhythm again amidst change and the unknown.
When running enters the mountains
At 7 AM on September 12, 2026, Yan Rujing stood at the starting line of the Dajingmen Ancient Great Wall Trail Run in Zhangjiakou. As part of the trail experience race that day, she was about to truly run into the mountains for the first time. After three years of exercise, Yan Rujing still hasn't genuinely grown to love running. In her view, running is almost a "cruel" sport that constantly exposes her physical flaws—"knock knees, hyperextended knees, and unstable ankles." Moreover, her physical capabilities decline too quickly in running; just one week off, and her cardiovascular fitness regresses to previous levels.
Before this, Yan Rujing had thought about it for a long time, always wanting to give it a try. She had run many urban routes, including a full marathon, but trail running always frightened her a bit, especially the ascents and descents. At 16, she had a hiking accident during a summer camp in Malaysia, falling and being carried down the mountain. For the following decade, she didn't dare climb again. So when the invitation to the Dajingmen trail experience race came her way, she still wanted to try once and conquer her fear. This experience run was only 5 kilometers with about 300 meters of elevation gain. Because the barrier to entry was low, it allowed more sports enthusiasts to participate in the trail running scene. The route wasn't too long, but it was enough for Yan Rujing to confirm her feelings about trail running. At 7:30 that morning, the temperature in Zhangjiakou was only around 15 degrees Celsius, but a group of trail running enthusiasts gathered together, brimming with energy as they awaited the start.
Once she actually started running, Yan Rujing quickly discovered that trail running wasn't the same as the urban running she was familiar with. City roads are mostly flat and predictable, presenting runners with a clear route. The mountains, however, are different—terrain, slopes, and weather can change at any moment. For a professional runner like He Fujun, it's precisely this unpredictability that he loves. In this Dajingmen Ancient Great Wall Trail Run, he competed in the 70-kilometer category. The varied terrain, elevation gains, and weather, full of unknowns, make every race different. It might be painful while running, but after finishing and looking back, it feels fresh.
Another runner, Luan Yushuai, has years of marathon experience, but during his first trail race in the mountains, seeing the forests and streams, his most immediate feeling was simply "so much fun." For Datong, this fun was more like a temporary escape from urban life. Working at an internet company and always enjoying outdoor activities, he remembers the specific details of the mountains from his first trail run in 2023—seeing pine branches fall, hearing cicadas and birds, and deeper in the mountains, light streaming through the shade of trees. These are things rarely felt sitting in an office. Before arriving in Zhangjiakou, Yan Rujing's imagination of trail running was similar—running in the mountains with good sunlight, wind blowing, and seeing many different landscapes. Once she actually ran in, she found that this vision had basically come true.
But the change brought more than just novelty. In urban road running, the movements and rhythm your body faces are relatively stable. In the mountains, uphills, downhills, steps, and gravel constantly appear, forcing the body to switch its exertion patterns. When He Fujun first started trail running, the muscle soreness was what he found hardest to adapt to. Different sections require different muscle groups, and he remembers the strongest feeling: throughout the race, he was "constantly wrestling with his muscles." Luan Yushuai's daily training volume is high, but in the mountains, continuous ups and downs quickly deplete leg strength, and on descents, the ankles endure constant impact. Even with just five kilometers that day, Yan Rujing quickly felt this too. Before starting, she was curious about "how can 5 kilometers have 300 meters of climbing?" She got her answer soon after the start. It began with a continuous flight of stairs, immediately challenging her intensity, with her heart rate quickly climbing to 160 beats per minute. The latter half shifted to continuous downhill and stairs. For someone who was already afraid of descents, this section required even more control. She could feel the impact on her knees and instinctively adjusted her pace. By the time the 5 kilometers ended, her calves were noticeably sore.
In just 5 kilometers, Yan Rujing hadn't yet truly experienced the exhaustion and limits of long-distance trail running, but she had already grasped the sport's most direct characteristic: the mountain path is always changing, and the body must change with it. The fun and the difficulty of trail running come from the same place. For Yan Rujing, the 5-kilometer trail experience made her realize that running can be something entirely different.
Yan Rujing reads her body's signals on the trail
The mountain environment is constantly shifting, requiring runners to make continuous judgments. Often, more important than perseverance is knowing where you are in that moment. Over the past three years, Yan Rujing has become increasingly accustomed to using data to understand her body. For this Dajingmen race, she was also a member of the "JD Watch Team." This marks the first time JD's 3C digital division has delved deeply into the trail racing scene. As a supporter of professional sports equipment, JD aims to bring smart wearables from daily life onto real racecourses, ensuring smartwatches aren't just tracking steps, time, and distance, but truly participating in route judgment, body monitoring, and risk management in complex mountain environments. Before the start, Yan Rujing loaded the race route into her watch. Once in the mountains, the two data points she checked most were the route—knowing where she was, allowing her to anticipate the final uphill and adjust her pace—and her heart rate.
Beyond racing, the smartwatch has become a crucial device in Yan Rujing's daily life. She often sleeps wearing it. HRV (heart rate variability), sleep, and resting heart rate are the metrics she checks in the morning. These indicators help her adjust the day's training plan. If her HRV is very low, signaling the body hasn't adequately rested and recovered, she and her coach will reduce the originally planned training intensity. She once tried ignoring fatigue, thinking she could push through, but found this made her more prone to injury. Now, data serves as a direct signal from her body. This shift is also happening for many long-time runners. For numerous trail runners, the smartwatch is becoming increasingly important. When Luan Yushuai first started using a smartwatch, he only looked at three numbers: pace, distance, and time—needing only to know how fast, how far, and how long. Later, as his training became more systematic, he began focusing on heart rate, cadence, training load, fatigue, and recovery time. These numbers aren't just records of exercise; they've also become part of his decision-making. For a 100-kilometer trail race, if the first half is relatively flat road running followed by significant climbing, he won't push the pace too high initially. If the watch shows a notably high heart rate shortly after the start, he'll realize "am I running too fast, pushing too hard?" and proactively slow down.
For professional runners like He Fujun, data can even influence training plans over a period. Before a race in France, he might have continued completing several high-intensity training sessions with his teammates, but the watch showed his body was already in a fatigued state during that period. Ultimately, He Fujun chose not to push fully with his teammates, instead lowering the training intensity based on his own recovery. Datong had an even more direct experience. Before the Wuhan Marathon in March this year, he had three consecutive days of business travel, hopping to a different city each day with work often extending late into the night. He had originally planned to finish that race under 3 hours and 30 minutes, but shortly after the start, the watch showed his heart rate had hit 160 bpm—10 to 15 beats higher than usual at the same pace. He quickly abandoned his original goal. In that race, Datong didn't chase the 3:30 finish time but opted for a more conservative approach to finish safely. He later said that had he not checked his heart rate and continued pushing toward his original target, "I might have collapsed mid-race, or even dropped out."
The meaning of these data points is equally concrete for ordinary runners. Zhang Jing participated in the 30-kilometer category at this Dajingmen race. She bought her first smartwatch after getting lost on Beijing's Sanfeng mountains. Without navigation, she couldn't descend as planned. After that, she felt she had to have a watch. Now, she increasingly trusts these prompts. Many times, subjective feelings tell her she can push through one more time, but if the watch keeps alarming and her heart rate remains above the limit for an extended period, she chooses to slow down. For her, chasing a few more race positions is far less important than long-term health. Her principle now is "health first, finish safely." Electronic devices can't fully make decisions for runners, but on a trail full of changes, they can make things that were once vague visible. These data points ultimately point to one's understanding of their own body. JD's 3C digital division entering the trail racing scene is precisely to show more ordinary runners that smartwatches are becoming increasingly professional. JD is also simultaneously pushing smartwatch brands to continuously upgrade with more new features for trail racing. Yan Rujing increasingly feels this—smartwatches are becoming more precise. Often, her subjective body sensations and the data are almost in sync. During this Dajingmen run, her intuitive feeling was that she could talk and was sweating slightly. Looking down at her watch, "the heart rate was indeed 160 (bpm)."
Bringing the wild back into daily life
Over the past three years, Yan Rujing has tried many new sports. She's run marathons, participated in HYROX, climbed mountains, and recently started learning boxing. Every time she switches to a new activity, she realizes once again that her understanding of her body is far from complete. Every time she thinks she's "finally in decent shape," she discovers she's still a beginner. After three weeks of boxing, she's already done sparring. She assumed that having run marathons and done HYROX, her fitness wouldn't be an issue. But boxing requires a completely different kind of short-burst explosive power. After just a few minutes of continuous punching, her shoulders tire to the point she can't lift them. As her sports portfolio grows, Yan Rujing becomes more aware of the importance of self-protection. Last year, she packed her schedule full of activities, and her knees finally reminded her with pain to "take it easy." The day before this trail run, she went to bed at 9 PM—running requires ample energy. This is one of the most important lessons sports has taught her in recent years: without self-protection, "your athletic career could end in no time." Self-protection is for the sake of being able to exercise long-term. This is also the change that occurs when sports gradually enter ordinary people's lives. Initially, one might want to challenge themselves, but when exercise becomes a habit, it becomes part of life itself.
Zhang Jing is the same. At 42 this year, for a long time her life was almost entirely work and family, with no time for herself. Running and going to the mountains were squeezed out bit by bit from such a life. She doesn't have a professional runner's complete training plan. She runs 10 kilometers after work when she has time, or goes to the mountains with friends on weekends. Gradually, these fragmented moments have transformed into a stable space in her life.
What Datong rearranged was his life approaching 40. Working at an internet company for years in branding and HR, as his career neared a bottleneck, he began seriously pondering what different things he wanted to do after turning 40. Trail running gave him a framework for understanding life. In the mountains, there are always things that can't be planned—sudden weather changes, unexpected physical discomfort, or failing to meet set goals. After running for a while, Datong increasingly accepts that not every race must be completed through gritted teeth. Sometimes you continue, sometimes you withdraw. What matters is assessing risk and understanding your boundaries. He later found that this kind of judgment isn't so different from real life.
For Luan Yushuai, running brought a path he never could have imagined. When he first ran the Beijing Marathon in 2017, he was an ordinary delivery courier. Daily deliveries and climbing stairs were his biggest physical activities. Later, he began training seriously, running marathons, and then entering the mountains for more races. Looking back over the years, Luan Yushuai feels running has changed not just his body, but also his approach to life. Previously, when faced with unsolvable problems, he was prone to anxiety, impatience, and even giving up. After running for so long, he's grown accustomed to the idea that things require day-by-day accumulation. For these individuals, exercise ultimately becomes more than just a race—it's about deciding anew what's important in life. Trail running perhaps embodies this even more: facing uncertainty, one can't control everything, but can regain control over themselves in every specific moment. Just like this trail run, with every step on the ground, Yan Rujing said she could feel a slight sting from her foot contacting the earth. Even with a bit of numbness, every step felt grounded. The most memorable part of the 5 kilometers for her was the final stretch. The wind blowing on her, knowing the finish was in sight, Yan Rujing took out her phone to capture the mountain scenery. Mountains on the left, the city on the right, and a clear blue sky overhead—she felt a sense of vitality and thought it deserved a memento. "There's no need to rush through the run," she said.
In a way, this is the significance of ordinary people stepping into the mountains. It's not about breaking limits every time, but about finding your own rhythm again amidst change and uncertainty. Just as every mountain story is reached step by step, every old watch has recorded a person's earnest life, training, and journeys. To ensure these companions are more than just relics of the past, JD's 3C digital wearables division, in partnership with Aihuishou, has launched the "Old Watch New Life" program: regardless of which brand of smartwatch you previously wore, you can trade it in at JD for a new watch, receiving up to 800 RMB in subsidies on your purchase. Old watches for new life, regardless of brand. It once recorded your heart rate, routes, climbs, and horizons; now it can become the boost for your next departure. Open the JD app and search "Old Watch New Life" to let your next watch continue running with you into the wild.
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