From Road Marathons to UTMB 100 Miles: Chunsic’s Epic Journey
A South Korean Runner’s Path from Road Marathons to One of Trail Running’s Most Iconic Races, the Ultra-Trail Mont-Blanc, UTMB 100 Miles.
Chunsic Lee’s transition from road marathons to completing the 100-mile Ultra-Trail du Mont-Blanc (UTMB) is a powerful story of determination, growth, and overcoming fears. Like many marathon runners, Chunsic was concerned about the technical demands of trail running—especially when faced with the daunting UTMB. However, with hard work, dedication, and guidance from Arduua Coach Fernando, he successfully completed one of the most iconic and challenging trail races in the world.
The UTMB is not just a race; it’s a journey around the Mont Blanc massif, crossing three countries: France, Italy, and Switzerland. Spanning 176 kilometers with a grueling 9,900 meters of elevation gain (D+), the UTMB tests runners’ endurance, skill, and mental toughness. Every year, thousands of trail runners from around the globe come together to experience the beauty and challenges of the Alps. It’s considered one of the pinnacles of trail running.
Chunsic’s journey shows how perseverance, along with the right preparation, can turn even the toughest challenges into achievable goals.
Meet Chunsic Lee, a passionate trail runner from South Korea and part of the Arduua Trail Running Community and Team Arduua. Recently, Chunsic accomplished an incredible feat: he completed the UTMB 100 miles, one of the most prestigious and challenging trail races in the world. We had the pleasure of catching up with him to learn about his journey, his preparation, and his race-day experience.
Can you introduce yourself?
I am from South Korea, and I’m 43 years old. I work as a developer, and in my free time, I’m deeply passionate about trail running and road running. Currently, I’m not married, so I can dedicate most of my time outside of work to running.
How did you get into trail running?
I started trail running in 2018 after I got into full-course road marathons. The transition to trail running felt natural. I began with a 10km trail race and quickly set my sights on longer distances—first 50km, then 100km, and eventually 100 miles. Trail running offers a fresh experience in every race, which makes it so engaging for me.
You dreamed of running the UTMB 100 miles. When did you first set this goal, and what motivated you to pursue it?
In 2023, after I achieved my goal of completing a full-course marathon in under three hours, I started thinking about the next challenge. For trail runners in South Korea, the UTMB is like the ‘final boss.’ It’s regarded as the ultimate challenge in trail running. That’s when the dream of running the UTMB was born for me.
You made it to the UTMB finish line! 100 miles in mountain terrain!! Congratulations!! How was it?
Before, during, and even after the race, I was blown away by the incredible support from the local residents. Their encouragement made the entire experience unforgettable and filled with emotion.
I had been warned by other Korean participants that the food at the checkpoints (CPs) might not suit everyone, so I took the precaution of bringing my own food. For me, nutrition was key, and ensuring I could eat well was critical to making it through the race. Thankfully, the CP food worked out great, and I didn’t have any stomach issues.
I thoroughly enjoyed the long, grueling uphills and steep descents. These kinds of terrains are rare in Korea, so I was excited by the challenge. While the terrain itself wasn’t overly difficult for me, the toughest challenge I faced was fighting drowsiness throughout the race.
Crossing the finish line was nothing short of magical. The crowd erupted in cheers, welcoming me with such warmth—it’s a moment I will never forget. As I approached the end, there was a surge of joy and pride, but in the exact moment I crossed the finish line, I was surprisingly calm. It simply felt like, “It’s over.” It took some time to truly grasp what I had accomplished. Even now, it still feels a bit surreal. After two years of intense preparation, stress, and hard work, completing the UTMB remains one of the greatest moments of my life.
How did you prepare for the UTMB in the months leading up to the race?
Since May, I’ve been training with Coach Fernando from Arduua. The training was tailored to help me achieve my UTMB goal. We started gradually, building up stamina, flexibility, and strength.
During the week, I would do fartlek training, jogging, strength workouts, and more jogging. Weekends included hill, downhill, altitude, and long-distance runs. Finding hills in Korea for proper training was challenging, but I managed to make it work. I averaged about 200-300 km of running per month.
You joined Arduua Coaching in May to help you prepare for UTMB. What were your expectations, and how has the Arduua training helped you?
My biggest expectation was to improve my downhill running, which was my weakest point. Thanks to Arduua’s strength and flexibility training, I was able to overcome this. During the UTMB, I maintained my pace well on the downhills, which was key to completing the race successfully.
How has your experience working with Coach Fernando been?
Fernando provided weekly feedback on my condition and adjusted the training accordingly. Communication was sometimes challenging due to language differences, but Fernando made every effort to understand me. As the race drew closer, he gave me valuable advice on how to manage a 100-mile race, which helped me complete the UTMB. I’m truly grateful for his guidance.
What do you think of the Arduua Global Community?
Although I’m in South Korea, I always feel connected to Team Arduua. I haven’t met the team members in person yet, but I believe we will meet one day. The bond between Fernando, Katinka, and me is strong, and I hope to connect with more teammates in future races.
Now that you’ve conquered the UTMB, what are your next trail running goals?
My next race is the Trans Jeju 100k, followed by the Japan UTMB race in June next year. My ultimate goal, however, is to compete in the Western States. It’s one of the hardest races to get into, but the challenge of its short cutoff times is appealing to me.
What advice would you give to other runners who dream of taking on races like the UTMB?
If possible, it’s a good idea to have fellow runners by your side during the race. Running with a group is better than going solo. You can support each other, share advice, and it makes the race less monotonous. I had the pleasure of running the second half of the race with a Korean couple, and we crossed the finish line together, feeling happy.
Conclusion
Chunsic’s journey to the UTMB finish line is a testament to his dedication, training, and perseverance. From the early days of road marathons to conquering one of the most epic trail races in the world, his story is an inspiration to all trail runners.
Interested in Joining Arduua? Here’s How We Can Help:
To prepare for this monumental challenge, Chunsic used the Race Coaching package from Arduua, which played a crucial role in helping him achieve his goal. Whether you’re aiming for the UTMB, a local trail race, or simply want to become a stronger, more confident trail runner, Arduua’s Online Coaching programs can provide the expert guidance you need to succeed.
Our Race Coaching package is ideal for runners like Chunsic who are preparing for specific races and need tailored training plans to meet the demands of the event. But we welcome trail runners of all levels from around the world to join Team Arduua. Our personalized coaching can help you tackle any trail running goal you set.
If you’re ready to elevate your trail running and take on new challenges, check out our Trail Running Coaching Program today! 🌍
Learn more about our coaching packages here:
👉 Arduua Online Coaching
/Blog and interview by Katinka Nyberg, Arduua Founder