An Arduua Athlete Faces His Toughest Challenge Yet
For passionate trail runners, there are races that push the body and mind to the extreme—and then there is OBT Oslo Bergen Trail 500km.
This summer, Fredrik Alfredsson, Team Arduua, will take on the race’s inaugural solo class, facing one of Scandinavia’s toughest ultra-endurance challenges.
Fredrik, a seasoned ultra-trail runner with a deep love for adventure, is no stranger to extreme conditions. Having conquered races such as Sandsjöbacka 180K in brutal winter terrain (winner) and Trail Valle de Tena 80K/6660D+, he now sets his sights on a 500km journey across Norway’s wild landscapes. With 16,000 meters of elevation gain, self-navigation, and unpredictable mountain conditions, OBT will test every ounce of his endurance and strategy.
What is OBT Oslo Bergen Trail 500km?
The Oslo Bergen Trail (OBT) is a 500km mountain ultra from Oslo to Bergen, following the rugged trails of the Norwegian Trekking Association (DNT). Runners face a variety of terrain, from marked paths to non-existent trails, traversing forests, alpine regions, and remote wilderness.
- 16,000m of elevation gain/loss
- Self-navigation required (GPS, paper maps, compass)
- No private support allowed (Only organizer-provided aid stations)
- 8 service checkpoints with food, rest areas, and drop bags
- Mandatory gear includes a sleeping bag—runners decide when and where to sleep
This year marks the third edition of OBT and the first time a solo class is introduced. The previous winning team finished in 6.5 days, and Fredrik’s goal is to complete the race within 6-7 days—a feat requiring extreme endurance, smart strategy, and mental resilience.
Fredrik Alfredsson: A Trailblazer in Ultra-Endurance
Fredrik has been part of Team Arduua for over four years, continuously pushing his limits in some of the most demanding ultra-trail races. Beyond running, he balances family life and managing a horse farm outside Gothenburg while dreaming of building an eco-lodge in Spain’s mountains. His approach to endurance isn’t just about racing—it’s about a lifestyle rooted in passion, self-improvement, and a deep respect for nature.
“The idea of being out in the wild for a whole week, completely self-sufficient, is both exciting and terrifying,” Fredrik admits. “It’s a challenge I’ve never faced before, and that’s exactly why I’m doing it.”
A key part of Fredrik’s journey has been his coach, Fernando Armisén, Arduua Coach, who has been guiding his training from the very beginning. When Fredrik started with Arduua four years ago, he was new to structured training. Under Fernando’s guidance, he has built the endurance, strength, and race strategies that now allow him to take on some of the world’s toughest ultra-trail challenges.
In addition to Fernando’s coaching, the Team Arduua Community has played a vital role in Fredrik’s motivation and development. Meeting up with fellow team members at races, training camps, and weekly Vertical Sunday sessions in Gothenburg has provided camaraderie, encouragement, and inspiration. Having a supportive community of like-minded athletes has made the journey even more rewarding.
The Road to OBT: Training, Strategy & Preparation
Fredrik’s preparation follows Arduua’s Structured Training Methodology, ensuring he peaks at the right time. Unlike previous seasons, he has no scheduled races leading up to OBT—his training is entirely focused on race-specific endurance, navigation, and gear testing.
“My training is about building volume gradually. Right now, I’m in a base phase, training around 12-15 hours per week. As we get closer to summer, that will increase, and I’ll do test runs on sections of the OBT course whenever possible.”
Current Training Plan
Base Training (Feb-April):
- 12-15h training per week, increasing in blocks
- 40% running, combined with cycling, cross-country skiing, and skimo
- Strength training (one heavy session, one mobility-focused session)
- Long back-to-back weekend runs (2h+)
Volume Phase (April-June):
- Higher mileage focus
- Longer test runs on OBT sectors
- Race-pace simulations & sleep deprivation training
Final Preparation (June):
- Fine-tuning strategy: Rest, nutrition, hydration
- Tapering for optimal race readiness
Challenges Ahead: Mastering the Unknown
1. Sleep & Fatigue Management
Deciding when and where to rest is a critical factor in OBT. Sleep deprivation will take a toll, and Fredrik plans to test different strategies during training. Previous runners have used shoes 1-2 sizes larger due to foot swelling—another crucial adaptation he must prepare for.
“I know that sleep will be a huge challenge,” Fredrik explains. “I have an initial plan, but I’ll adjust it based on how I feel during my test runs. Managing fatigue smartly will be key to finishing strong.”
2. Navigation & Terrain
OBT requires runners to navigate with GPS, paper maps, and a compass, as only permanent DNT markings exist. With vast sections of the race lacking trails altogether, Fredrik is preparing by running test sections in advance.
“I’ll try to cover as much of the course as possible before race day. The terrain varies so much—it’s important to know what to expect.”
3. Mental Resilience
A week alone in the wilderness is an immense psychological battle. Fredrik knows that being alone for so many days, making smart decisions while tired, and managing energy efficiently will be his biggest challenge. But this is exactly what excites him about the race—pushing his body and mind further than ever before.
“What excites me most is not knowing how I’ll feel on day four, day five… That’s the unknown I want to explore.”
What’s Next After OBT?
While OBT is the year’s main focus, Fredrik plans to return to racing in autumn, competing in the Outnorth Trail Tour with Team Arduua. He also has his eyes set on Ladonia Mountain, a 48-hour adventure race requiring navigation, self-sufficiency, and swimming—another exciting test of endurance.
Dream Big, Train Smart, and Conquer Your Own Challenges
Fredrik’s journey is a reminder that the greatest adventures start with a single step. Whether you dream of tackling your first trail race or taking on an ultra-endurance challenge like OBT, the right preparation, mindset, and support system can make all the difference.
At Arduua, we believe that every trail runner has untapped potential. With expert coaching, structured training plans, and a community of like-minded athletes, we help runners push beyond limits—just like Fredrik is doing.
Do you have a big goal in mind? Let us help you make it a reality.
Join Arduua’s Trail Running Coaching today and start your journey toward your next adventure!
/ Katinka Nyberg, CEO & Founder of Arduua