Transitioning from Cycling to Trail Running – Early Season Build for UTMB

By Jonathan Edwards

After finishing a winter cycling block and recent BWR Arizona event (a 104 mile gravel bike race), my focus has now shifted to reintroducing running as I prepare for UTMB. Ultra-Trail du Mont-Blanc (UTMB) is one of the world’s largest mountain ultras. Covering roughly 170 kilometers (106 miles) through the Alps with 10,000 meters (33,000 feet) of vertical gain, UTMB takes runners across France, Italy, and Switzerland through rugged mountain terrain. It’s a race that tests physical endurance, mental toughness, and technical skill under extreme conditions.

Macro Build Phases & Key Objectives

• March–April: Base & Transition Phase

In these early months, I’m reintroducing trail-specific running after a prolonged cycling phase. There will still be cycling intermixed to accumulate aerobic volume while running is increased, but as the running volume comes up, cycling will decrease. The focus is on gradually increasing weekly mileage and vertical gain, including strategic use of incline treadmill workouts during inclement weather to mimic the required efforts. There will be light sprints and strides introduced as well as shorter intervals to wake up the anaerobic system and neuromuscular response.

• May–July: Peak Training Load & Specificity

This is the heart of my build-up. During these three months, I’ll push my weekly volume and vertical gain to simulate UTMB conditions as closely as possible (peaking around 20-25+ hours in a week with a heavy focus on vertical gain – targeting 30,000+ feet). I’ve signed up for an early season trail marathon in mid-May—a “rust buster” and fitness check—to gauge my early progress. In addition, I’m targeting two training camp weekends (three days each) in mid-June and early July. These camps will allow me to test my gear, nutrition, pacing, and running on tired legs. As a final race prep rehearsal at the end of July, I will complete a local 50K that has a similar profile to UTMB.

• August: Sharpening & Taper

In the final month, volume is slightly reduced while maintaining intensity. This phase is focused on refining pacing strategies, optimizing recovery, and ensuring that every element—from gear to nutrition, is fine-tuned for race day.

Base & Transition Phase Specifics
After a quick recovery at the start of March, I switched my focus to building back my running volume. During this early season build through March/April, my primary goal is to re-adapt my body to the high-impact demands of mountain running and to begin to introduce faster intervals to encourage leg turnover and efficiency.

The Importance of Increasing Gradually
In the week following BWR Arizona, I logged 5 hours of running along with 1 hour of cycling, all at recovery effort. While cycling provides an excellent aerobic base and I have a history of higher running volume, it is smart to slowly increase the volume due to the impact forces that come with running. You probably have heard of the 10% rule, but that is extremely broad and depends on each person’s training background and the composition of the running. Easy jogging, hard intervals, and mountain running with vert are all different stimuli and should be treated as such. I am trending towards 13-15 hours of running per week at the end of April, including adding moderate vert. to some runs, and intensity to others, which I have already started to work in.
A note on measuring volume: I typically refer to volume mainly in terms of time, rather than miles. This is due to the fact that distance does not factor in terrain, conditions, or vertical gain. 10 miles on a flat road is a much different load than 10 miles on a technical or snowy trail with 5,000 ft. of gain. Using time is not perfect, but is a better way to calculate volume especially when training across multiple domains (road, trail, treadmill, cycling, etc.)
Caption: Running volume build (completed) from 5 hours to 12 hours the first 5 weeks after BWR Arizona

Structured Workouts and Gradual Progression
My training schedule during this phase combines outdoor trails, road running, and indoor treadmill sessions when desired. I will supplement with cycling as needed to keep overall aerobic volume high while my legs catch up to the impact. The treadmill is monotonous, but sometimes it is the easiest approach to execute a training run without interruption. Other days, I’ll run on local trails that offer moderate technical challenges while targeting 200–300 feet of vertical gain per mile. The goal during this phase is to increase volume, terrain matters less at this time, and specificity to the race will follow.
Specifically here is what a typical week looks like (week of March 24):

• Monday: No running / strength training
• Tuesday: (AM) 75 minutes running w/ 2 sets of 7×1 minute pickups and 1 min recovery between (PM) Strength training
• Wednesday: (AM) 70 minutes Z1/Z2 w/ 6x 20s strides / (PM) Strength training
• Thursday: 2 hour endurance trail run w/ moderate vert (2,392 ft.)
• Friday: 70 minutes Z1/Z2 w/ 6x 20s strides
• Saturday: (AM) 90 minutes with 4×8 minute tempo run incline (6-8% grade on trail) / (PM) Strength training
• Sunday: 3 hour endurance run (road – which will transition to trails as the snow melts)

Expected Outcomes
By the end of this early season build, I expect to see improvements in my running economy and prepare my tendons/ligaments for the workload to come over the next 4-5 months. I expect to increase volume and recover appropriately, using subjective measures (how do I feel) and objective (HRV and heart rate during training) to make sure I am not digging myself into a hole before the real work starts.

What’s Next
This is just the first step in my UTMB preparation. I’m laying a robust foundation for the race-specific training to come. In the coming months I will start to focus on specific gear testing, tune up races, training camp weekends, and dialing in nutrition.