Cross-country skiing: strength, drafting, and training
Summary: With the cross-country skiing season approaching, this article reviews three studies from 2019 that explore what influences performance in modern cross-country skiing. The central question is what truly makes the biggest difference on the track: strength and poling technique, conserving energy through drafting, or the structure of the training plan over an entire year. First, we examine research on maximum strength and its relation to effective poling. Next, we delve into what science reveals about air resistance and the benefits of drafting. Finally, we compare two different training philosophies of one of the sport’s most successful skiers. The conclusion: multiple strategies can be effective – but the finer details are crucial.
Three studies from 2019 on performance in cross-country skiing
As the cross-country skiing season nears, gaining fresh insights in the field is beneficial. Below, we review three intriguing research studies from 2019 that examine various aspects of performance in cross-country skiing. We begin with maximum strength for enhanced poling, proceed to air resistance and drafting in modern skiing, and conclude with an analysis of the world's greatest cross-country skier and her training routine.
Max Strength for Better Double Poling
The evolution of classic cross-country skiing has increasingly emphasized the importance of double poling. The rise in speed is due to advancements in equipment and materials, with more races starting in mass, making double pole sprints and bursts more crucial. In long-distance races, many elite athletes have transitioned to exclusive double poling. For Olympic distances, pole-free zones have been introduced, and the hills have lengthened and steepened to counter races relying solely on double poling. There's enough material here for an entire podcast discussion 😉, but let's focus on something else for now. Regardless of your skiing style, mastering double poling is essential these days. This is where our first article begins.
Stronger Is Better: The Impact of Upper Body Strength in Double Poling Performance is a Norwegian study from August 2019 that aims to compare double poling (Double Poling (DP)) during a time trial (TT) with other physiological variables like maximal oxygen uptake (VO2max), max strength, threshold, and power development.
The study hypothesized that the double poling tests would correlate with upper body max strength. It involved 16 women and 12 men, aged 16–25 years. All participants were well-trained athletes with a VO2max of 54 ml/kg/min for women and 64 ml/kg/min for men. The researchers found that VO2max tests on the treadmill were good indicators of TT performance. However, strength tests were also quite relevant. It was seen that the variables "contact time" (CT) and "peak force" (PF) best correlated with the TT test.
One conclusion was that skiers with the highest value in one repetition maximum (1RM) pulldown (lat pulldown) also had the highest peak force (PF) and the shortest contact time (CT). These variables have been linked with faster skiers in previous research. A higher 1RM pulldown allows skiers to work at a relatively lower percentage of their max during double poling at a given load. In essence, being strong helps reduce muscle load during exertion, allowing you to maintain speed for longer without losing power—or, conversely, gain more power in each pole stroke over a shorter distance.
Max strength plays a crucial role in many endurance sports, forming a key part of a well-structured training plan. Based on the study, researchers recommend skiers incorporate max strength with 2–5 repetitions over 3–5 sets in their training to enhance work efficiency and max strength.
The tests were conducted on roller skis, where there are higher speeds and more benefits from double poling. Future tests in various snow conditions would certainly be interesting.
If you're keen to dive deeper, you can find the article here:
Northug's Tactic: Drafting and Air Resistance
The next article is from Sweden. Mats Ainegren at the Sports Tech Research Centre, Mid Sweden University in Östersund has studied the effects of “drafting,” which means reducing air resistance by skiing behind another athlete. This is something Petter Northug implemented and optimized during his career with great success!
In cycling, it's a given that there's a big advantage to "slipstreaming," and being part of a pack can save up to 30%. Even in cross-country skiing, it's long been known that at certain times and under certain conditions, it's beneficial not to lead. But what exactly does science say about this—how much can one gain by skiing behind?
Tests were conducted on a large treadmill in a wind tunnel. They compared skiing alone or behind another skier. A total of 10 elite female and 10 elite male skiers participated. They measured oxygen consumption (VO2) and heart rate. These tests were also performed at different speeds with corresponding wind speeds. The skiers skied classic and only used the double-poling technique.
The study found that at speeds over 5 m/s (18 km/h), there was a significant difference in both oxygen consumption and heart rate when skiing behind another athlete. The difference was 3–5% for males while women had 2.5%, but it required a speed of 6 m/s (21.6 km/h) to see the same effect. Such fast speeds, especially for the usual Vasaloppet skier, are not uncommon in good conditions on the Vasaloppet marshes. If there's additional headwind, the effect increases and can be noticed at lower speeds. Also, remember that the snow conditions matter: new snow or heavy conditions make it harder to be in the lead. The effect should also be greater in classic technique than in skate skiing as it's easier to stay close and ski in the same tracks in a classic style. 3–5% might not sound like much, but over a longer race, it can have a big impact. Researcher Mats Ainegren explains it well himself:
“Leading in a race, and thereby facing greater air resistance, makes the same difference as skiing with correspondingly poorer technique or waxing. You expend more energy and become more tired compared to those who ski with more efficient technique or with less friction between ski and snow.”
So find a good big back and save energy. Of course, you can take a turn at the front and share the lead work, or wait for the sprint 😉
Read the full article here:
https://www.idrottsforskning.se/sa-mycket-energi-sparar-elitakaren-pa-att-kora-northug-taktiken/
The World's Greatest Cross-Country Skier of All Time and Her Training, Block vs TRAD
We've come to the final article, and we're wrapping up with an intriguing study on the world's greatest cross-country skier of all time, with 8 Olympic gold medals, 18 World Championship golds, and 114 World Cup wins. Guess who it is 😉 What's fascinating about Marit Bjørgen is that she has trained under both a traditional progressive schedule (TRAD) and a more block-polarized one with relatively high-intensity blocks (BP).
This study compared the training year 05/06 when she trained BP with the 14/15 season when she followed the TRAD schedule.
The criteria for the two years were that the training load was equivalent and that similar performance results were achieved. Meaning: she won both the sprint and distance World Cup both years!
What was observed when comparing these years was that the total training load was the same, but during the BP year, the training volume was lower: 795 h for BP versus 938 h for TRAD. On average, this corresponds to 15 ± 6 and 18 ± 7 h/week respectively, leading to a reduction of about 3 h, or roughly 15% lower training volume per week. The major difference lay in more low-intensity training during the TRAD year.
The training intensity distribution between low-intensity, medium-intensity, and high-intensity was for TRAD and BP; 92/4/4 % and 88/1/11 %. Initially, the difference doesn't seem significant, does it? However, the number of high-intensity sessions (HIT) during the BP year was almost double that of TRAD and among the highest ever recorded for an elite athlete in endurance sports. In total, Marit completed 155 HIT sessions during the BP year, but only 77 HIT sessions during the TRAD year. Another difference between the two training philosophies was that during TRAD, the focus during the buildup period was on a lot of low-intensity training to build a stable foundation and then gradually increase the high-intensity training as competitions approached. In BP, instead, a major focus was placed on the high-intensity training early on to quickly gain adaptations in VO2max and then lower the intensity as the competition season approached — this was to utilize a strong “engine” in the remaining training close to the competitions.
This data shows that there are different training philosophies that can yield good results. Endurance athletes often like to dive into details about how many or how long intervals to do or how to set up periodization. This study suggests instead that focused training over time yields results. And for those who claim that distance doesn’t provide anything and that the focus should be on intervals: remember that during BP the focus was on high-intensity intervals and Marit did many of them! Yet they only account for 11% of the total training volume.
A caveat of this study, however, is that it is done on a single person — no matter how skilled she has been, the results cannot be generalized to a larger population without further investigation. Moreover, BP and TRAD were investigated almost ten years apart and a lot changes with an athlete over ten years. The skiing sport has also changed during the period with more mass starts and more sprints. Nonetheless, it remains an interesting read and the lesson is that there are several paths to success. Experiment and don’t be afraid to try new training methods!
Here you can read the full article:
https://www.frontiersin.org/articles/10.3389/fphys.2019.00375/full