Winter in the Northern Hemisphere is in full effect, with snow falling and our runs turning into slushy shuffles. Our winter seasons are often full of lofty goals for the months ahead, but the short days and cold weather do not help with our motivation to get outside and run.
In this article, we will explore the data to see what the winter months look like in the ultrarunning world. We’ll then dive into some data-based training approaches for tackling the winter season effectively.
iRunFar’s Craig Randall braving the elements to test winter mountain running gear. Photo: Christin Randall
Ultramarathon Racing in the Winter Season
To understand what the running landscape looks like during the winter months, let’s turn to the numbers. For this first analysis, we use data from the DUV Ultra Marathon Statistics database for U.S. races. The dataset we focus on is ultramarathon races in the United States from 2022 to 2024, with at least 10 participants. This first view shows the number of races by season.
Number of ultramarathons in the U.S. from 2022 to 2024 by season.This graph shows the lower frequency of races in the winter months, defined as December, January, and February for this article, than in the other seasons.
Breaking this down month-to-month, we can see a more detailed view.
Number of ultramarathons in the U.S. from 2022 to 2024 by month.
The winter season in the U.S. starts in December and continues into January and February. The number of races increases in the spring months, with a slight dip headed into the hot summer months, and then picking back up in the fall season.
Winter and summer, of course, are not equal in all states. Winter in Louisiana is a great time to get outside and be active, but you may want to wait a few months if you live in Minnesota. I wanted to break down these races by geography, to see what the distribution of winter events was like by location. The following graph shows the percentage of ultramarathons by state that take place in the winter.
Map showing the percentage of ultramarathons that take place in winter by state.
Most northern states have less than 10% of races happening during winter. States with more moderate or warm climates see a larger percentage of races occurring during this time frame. Louisiana was the only state with the majority of its races taking place in winter.
In most locations, winter is the season with the fewest ultrarunning events. This quieter time of year provides an opportunity to reset and focus on improving weak areas for the season ahead. If you live in a region that experiences winter, getting outside on dark, cold evenings is likely less appealing. This is something I struggle with, having lived in the northern half of the United States my entire life. With several ambitious plans for the spring and summer months, I dove into how to make the most of this winter.
What We Can Learn from Kilian Jornet’s Winter Training Data
Looking for inspiration for our winter training journeys, we turned to the GOAT, Kilian Jornet. Comparing yourself to him can be a self-defeating spiral, but there are some valuable lessons to be learned from his approach to the winter months — and so much data!
After a historic 2022 season, with wins at the Zegama Marathon, Hardrock 100, and UTMB, Jornet published a detailed training log. The log recounts his 2022 season in detail, and provides the context of all the years of continual training leading up to that point.
Chart showing an overview of Kilian Jornet’s training from 2009 to 2022.
The above chart shows a quick overview of Jornet’s training data going back to 2009. The red circle is the 2022 season. The main takeaway from this chart is that Jornet has been consistently putting in a lot of training volume year after year, leading up to his amazing performances in 2022. He notes that looking at the red circle in isolation is useless without the context of previous years of training and adaptations.
Kilian Jornet, 2022 UTMB champion. Photo: iRunFar/Bryon Powell
The part of this graph that stuck out to me is the repetition of blue bars every winter where his training turns primarily to ski mountaineering. Let’s focus on these ski mountaineering sessions that Jornet does during his winter block. Jornet lives in a cold winter climate in Norway, and the training during these months is adapted to the conditions. His winter block in 2022 went from December to the end of March, with most of his training being ski mountaineering in heart rate zone 2. These outings usually lasted two to four hours, often followed by treadmill running in the evening. See a zoomed-in version of what this looks like.
A zoomed in version of the above chart shows the breakdown of Kilian Jornet’s 2022 training, including a winter block which was primarily ski mountaineering.
With the main training being shifted to long ski mountaineering sessions, the running volume is significantly cut down. It is also interesting to note that Jornet does not do “any intensity except a couple of [ski mountaineering] races” during this period. This is shown in the graph below, with no marks on the speed, tempo, or threshold sessions that he breaks down in his post, until later in the year when he enters a more focused training block.
Visual which breaks down Kilian Jornet’s run training for his 2022 racing season. Click on the image to view a larger version.
Jornet kept his intensity low throughout winter, and his training focused on building a strong aerobic base. This aerobic base came primarily in the form of ski mountaineering, with running volume quite low for an athlete at his level. During the 2022 winter block, Jornet averaged a modest 53 kilometers (33 miles) of running per week, which is boosted by the outlier of a 100-mile race done during this time, to test fueling. Below I have broken out a graph to show this running volume during this winter block.
A breakdown of Kilian Jornet’s running volume during his winter training block.
During the rest of the year, Jornet’s weekly mileage was kept around 150 to 190k (93 to 118 miles). This reduction in running mileage during the winter months allows him to build a great aerobic base through lower-impact ski mountaineering sessions. A strong aerobic base leads to various adaptations, which increase the efficiency of muscle fibers and improve one’s time to fatigue.
It is impossible to be Kilian Jornet, and I’m sure many readers don’t live near large mountains in Norway, and cannot dedicate four hours per day to training. While your winter training will likely not look like this, this detailed breakdown of training data provides a good model for framing the year ahead.
Winter is a great time to set the foundational fitness for the rest of the season. Structuring a winter block to cross train or improve weak areas can set you up for success in later seasons. The type of winter training might vary, depending on where you live and what activities you enjoy. It could be backcountry skiing, competing in the Tour Du Zwift, or Netflix and the treadmill.
A young Sophia Laukli on skis, proving you are never too young to start winter cross training. Photo courtesy of Sophia Laukli.
Several interesting studies support a cross-training approach between competitive seasons. This study examines the effects of substituting 50% of female distance athletes’ run training volume with cycling. The results show that cross training maintained aerobic performance compared to running. Another study comparing four weeks of outdoor elliptical bike training to running training yielded similar results in terms of performance maintenance.
Cross training can be a great way to stay motivated and continue training during the winter. Looking for some ideas to get you started? Check out this guide to cross training.
At the end of the day, the messages in the data are these: With fewer races in the winter months, we may want to turn to other training modalities to pass the season. Doing what you enjoy and is long-term sustainable will allow you to continue stacking bricks year over year. And while we may not stack as many bricks of ski mountaineering or running as Kilian Jornet, staying active in the winter months and building a strong aerobic base will set us up for race-specific training and races themselves later in the year.
Call for Comments
- What time of the year do you prefer to race?
- How does your running volume shift during the winter months?
- What is your favorite form of cross training?
