UTMB is the pinnacle of ultra trail running. Serving as the World Series final, it showcases the best elite athletes in Chamonix, France, during the last week of August each year. Having crowned some of the great champions of the sport, Tim Tollefson and Petter Engdahl have both entered their name into the 2023 start list to test their abilities against the best in the world. So how does a world-class athlete break down a course prior? How do they go about developing their race strategy? COROS had the unique opportunity to sit down with both athletes and dive deeper into their preparations for this year's final. Below is a deeper look into how a few of the best runners in the world aim to tackle the 100-mile course.

How To Breakdown A Course

Anytime athletes race an event, they should be analyzing the course to understand how it fits their strengths, as well as how it may expose their weaknesses. With UTMB being a 100-mile mountainous course, we asked Tim and Petter how they analyzed such a large course. The unique thing about these two individuals is that Tim has raced UTMB many times, whereas it will be the first time on the course for Petter. See below for their different mindsets heading into the race.


Its really important to focus on it in segments. If I were to think about it as just a 100-mile course, it becomes insurmountable and daunting. To counter this, I use five distinct segments to focus on. Each section is broken up by crew stations. If I can stay focused for one segment at a time and know I'll get to my crew after, it helps me narrow my focus and stay present for the challenge.


With this being the first time racing UTMB, Petter has done a bit more external research. He has noted watching past races, seeing how the field responds, and knowing the expected time elapsed for leaders at certain checkpoints.

I'm breaking the course into three sections. From the start to Les Contamines, I was to treat it as a warm-up. This is a relatively easy section of the course. I will aim to be near the front, but I just want to ease into the day and not overexert myself. The second section is from Les Contamines to La Fouley. This is when it will be dark and when I expect the real adventure to begin. I won't see my crew for a long time, so I will be focused on taking care of my body and legs as much as possible. Lastly, past La Fouly, is where the race will start for me. You enter the CCC course here, and I've had great success on that course. While I haven't raced those trails following such a long race, I know the course and will aim to push my limits at this point.

Strengths Heading into Race Day

As athletes look to maximize their performance, one key tactic should be to focus on their strengths. This is the largest opportunity to differentiate from the field and often puts athletes in favorable positions relative to their competitors. Below are what Tim and Petter view as their strengths and how they aim to maximize these on race day.


With Tim's past experience on the course, his focus on strengths is more so remaining present initially in the race and then being able to get to the final 50k of the race feeling strong.

The key portions of the race for me are the night sections. If I can remain focused and not allow my attention to fade, I know I can make up time in the last 50k. My strength is descending, and I drool at the thought of getting through the night and to the final 50k feeling strong. If I can get to the net downhill section of the course feeling good, this is where I think I can really push my limits and make a difference.


As a newcomer to UTMB, Petter relies on his training and his past race experiences to dial in his strengths. Living in Norway, he does plenty of vertical gain but also mixes in skiing in the winter to establish his VO2 and cardiovascular abilities on uphill sections.

I'm very confident in climbing sections. All of my training is done in the mountains, and compared to the field, I feel like I can climb more efficiently than the field. I often attack uphill sections when feeling good, or if I'm not feeling great, I know I can just sit in on uphill sections and recover. Based on how the race unfolds, I will decide to sit back and recover or push onwards on the harder uphill sections.

Adjusting Strategy Mid-Race

Over the course of 100 miles, it's impossible to plan for every factor perfectly. The best athletes can adjust on the fly and make split-second decisions to get them back on track. The ability to remain calm and flexible is what often makes the difference between allowing conditions to get the best of you or reframing your mindset to take on the challenge. Both Tim and Petter are well-equipped in this area and share some insights below.


The one constant in ultra running is that you can predict that it will be unpredictable. It's very rare that Plan A goes perfectly, so I have a lot of contingency plans that I know can be effective. The one thing you don't want to do is throw your hands in the air if a plan doesn't work. The more you dwell on a situation, the higher your perceived exertion becomes, which can negatively impact you in the long run.


I will base my decision based on the feelings in my legs. I often look at my speed when I'm moving and I know where I'm comfortable. I'm quite flexible in how a race unfolds because I know where my limits are and that I can't build too much lactate overall. While I have a strategy in place, my ultimate strategy is to move from point A to point B as fast as I can. If the race unfolds differently, I can always come back to my own knowledge of how my body performs. I need to be flexible and not chase people going faster than my comfort level, but rather, know where I can push and where I need to remain calm.

Visualizing Race Day

Another key focus for elite athletes at races is visualizing race day before you ever get to the start line. Research has shown that visualizing your performance can activate your brain and train the neuromuscular signals while also helping you understand how to deviate from a plan with a clear and concise focus. Both Tim and Petter are exceptional at this skill and share how they go about visualizing UTMB prior to the 2023 Final.


I do a lot of visualizations. It begins as early as my training runs in the month leading up. I visualize parts of the course, as well as things that may go right or may go wrong. In the past, I only visualized positive outcomes, but knowing what to do when things go wrong can be really helpful. In order to go through these visualizations prior to race day, I'll sit down for 30-60 minutes/day and go through the entire course and scenarios in my head. This way, I know I'll be prepared for anything.


I have been visualizing this race for quite some time and factoring in a lot of different scenarios. I'm also focusing on how it will feel the last 30k, how to finish, and how I will even feel at the start. This race is a completely new experience for me, so it's quite difficult to visualize the course as I don't know, but I can visualize how I may feel and work through those scenarios in my head. In order to focus, I ensure I'm lying down and am relaxed before going through a visualization focus. I have a mental coach that I talk with and go through different scenarios which also helps me quite a bit.

Confidence and COROS Metrics

The final part of any race day prep is having the confidence that you can execute on your plan A, B, C, or whatever the course throws at you. Both Tim and Petter have done everything they can to this point, and both build confidence from their prior training and what their metrics are telling them heading into race day. Both have unique metrics they focus on, but both are very confident that, given their training, their body is ready for the demands of UTMB.


COROS allows you to track weekly training load and volume

I gain a lot of confidence by looking at my COROS app and knowing my total run volume is there. Seeing the week-to-week consistency along with my peak weeks, tells me that I can handle the effort and my body is prepared. I feel good, and I'm in one piece following my large volume spikes. I feel very fresh in the week leading in and I know that I have a lot of hay in the barn, and I'm ready to burn it down.


Effort Pace and Actual Pace can be compared within the COROS Training Hub

Effort pace has been key to my training and building confidence. Whether I'm on my skis, in training runs, or even in my last few sessions, I use Effort Pace to dial in my pacing and know where my limits are. This helps me know that I'm physically ready for this and that the engine works. Another confidence building is the weekly mileage that I've done. This year has been far more consistent than past years, so I know my volume is there and what pace I can hold along the way.

Final Outcomes and Success

When talking with both athletes, they noted something that is very powerful for all athletes to hear. Both elite athletes noted that it isn't necessarily about finish placing but rather knowing that they have pushed their bodies and minds to the max on race day.

For Tim, he noted "Success for me at UTMB is not giving up on myself. When Plan A/B/C go out the window, and I execute plan D/E/F without cratering, that is a huge success."  In a similar fashion, Petter noted, "My successful day is knowing I have given everything out there. Push through the lows, enjoy the highs, and just be proud of my performance."  For many amateur athletes, they often fall into the trap of comparing themselves against others. However, when we look at two of the elite athletes at this year's final, they focus entirely on their effort and ability to control their mindset.

From breaking down the course, knowing their strengths, visualizing race day, and building confidence, both Tim and Petter have shown us what goes into a World Series final through the eyes of an elite athlete. As you train for your next major race, aim to incorporate some of these concepts to push your own limits and see what is possible.