Deep Dive Into Vasaloppet 2024 – Power Data, Performance Insights, and What Skiers Really Think

We have now returned to Gothenburg after intense days in Mora and Sälen. We finally had time to dig deeper into the responses from our Vasaloppet competition, where participants not only guessed the winners’ average power but also explained how they hope to use the Skisens power meter. The winner has already been announced, but as so often, the most interesting truths lie in the details.

How skiers want to use real-time power data

It is truly exciting to read how you skiers want to use our products and services. Many of you want to use the equipment to develop your skiing technique and improve your training. Others were more specific and said you aim to improve your Vasaloppet performance. A few of you even declared your ambition to win the race. A thrilling thought! When will we see the first Vasaloppet champion using a power meter — and what will we learn from it?

How much power does it really take to win Vasaloppet?

One question our power meters will finally answer — once the winners start using them — is exactly how much power is required to win 90 km in the tracks of our forefathers. This year’s estimates were based on empirical calculations from other skiers. Some have reacted that the required power sounds very high. And we agree: 180 watts for women and 275 watts for men over 90 km is extremely high. But these are incredibly well-trained athletes, so we should expect high values. The real question is: do we expect them to be this high? No one has ever measured this before.

Can you hold threshold power for an entire Vasaloppet?

Men’s champion Tor-Leif Syrstad quickly commented that 275 watts matches his threshold power on the SkiErg. This was fantastic feedback and a strong indication that our calculations are in the right range.
But wait — can anyone hold threshold power for a full Vasaloppet? Of course not. Functional Threshold Power (FTP), one of the most common measures, is defined as the power an athlete can hold for one hour (source).
This year’s Vasaloppet took nearly four hours, so we should expect a value around 10% below FTP. Research shows that average power drops by about 5% each time the work duration doubles.

Why our calculations still land on 275 watts

Based on our measurements and estimates, we still arrive at 275 watts. Why? Because threshold on a SkiErg is not the same as threshold on snow. Over the past five years, we have tested our handles on both recreational skiers and Vasaloppet champions, and what we consistently see is this:
strong skiers often reach higher power outdoors than on the SkiErg, while less experienced skiers do the opposite.

Why strong skiers can produce more power outdoors

For less experienced skiers, the explanation is simple: good technique is required to transfer force efficiently in the direction of travel. On a SkiErg, you can always force the power into the flywheel, regardless of technique.
For elite skiers, the opposite phenomenon is more interesting. One explanation is that technically skilled skiers benefit from the micro-rests that naturally occur outdoors, but not on an ergometer. The movement pattern on an ergometer is also more restricted, which can reduce movement economy. Studies in both running and cycling support this reasoning.

The influence of friction, drafting, and conditions

Of course, there are assumptions behind our calculations. The two most important parameters are glide friction and aerodynamic drag. Drafting has a significant effect at elite speeds. Friction also changes depending on how many skiers have skied ahead in the track.
Based on race results and performance, we have good reason to believe that Lager157 had exceptionally good skis. For this reason, we assumed that Syrstad’s skis had 10% lower friction than our test skis. The estimated 275 watts correspond to a friction coefficient of 0.025, which is moderately slow but far from extremely slow. As comparison, we measured 0.038 at Vasaloppet 2020.

Conditions for the broader field were much tougher

Even though the winners did not face extreme slowness, the race was far from easy for the majority of skiers. Friction further back in the field was likely higher, as the tracks broke down quickly in wet conditions. A metric illustrating this is the number of medals awarded.
On the men’s side, 1086 medals were awarded — historically low. For women, it was even harder: only 104 medals were awarded. This is less unusual, though, because the strongest women always start fast and stay in the slipstream of men. For medal trends over the years, see earlier posts:
https://skisens.se/2019/12/29/drommen-om-medalj/.

What skiers know about power — your guesses were impressive

One reason we arranged the power-guessing competition was to learn how much skiers actually know about power and what numbers are realistic. Based on your answers, many of you have an excellent feel for the wattage a skier can sustain.

Excluding outliers — including one who guessed a value comparable to a small motorcycle — the guesses for the women’s winner and men’s winner were both within one standard deviation of the average.
The guesses were:
Women: 235 ± 69 watts

Men: 283 ± 83 watts

Why it was easier to guess the men’s winner

It appears most participants guessed the men’s winner more accurately. Perhaps because the majority of Vasaloppet skiers are men and can relate more easily to power numbers for a male skier. One important detail some may have missed is body weight. Male athletes weigh roughly 25% more on average, which means women produce lower absolute power at the same performance level.
If we normalize the women’s winner’s power output to the men’s winner’s body weight, we get 225 watts — indicating that your guesses were remarkably accurate.

How much energy does a skier use in Vasaloppet?

Since this post has involved plenty of number crunching already, here’s a fun question asked at our booth:
How much energy does a skier use during Vasaloppet?
Power integrated over time equals energy, so the question is straightforward. What we need is the skier’s efficiency. Scientific studies place skiing efficiency around 18%. This gives:
Women’s winner: ~3700 kcal

Men’s winner: ~5000 kcal

To visualize this: 5000 kcal corresponds to 1.5 kg of uncooked pasta or approximately 8 liters of strong sports drink if consumed during the race.

How skiers want to use Skisens power meter

Before we wrap up, let’s return to the question of how you skiers want to use our handles. As expected — and very encouraging — many of you want to use them for intensity control and optimized training, just like in cycling. Many of you also wrote that you want to use the handles to ensure your outdoor training matches your performance on the SkiErg. That is spot on.

The SkiErg is fantastic because it is so measurable — but it will never fully replicate skiing outdoors. With Skisens handles, you can easily verify that your SkiErg improvements translate into real improvement on snow. A simple method is comparing your SkiErg power with your on-snow power.
If your outdoor power is lower, technique is likely the limiting factor.
If outdoor power is higher, your technique is already efficient and you can focus on building capacity.

We believe many more use cases will emerge as more skiers start using the handles. One special prize will go to the participant who gave the most poetic motivation:
“With love in every training session.”