Tjejvasan 2020: How Heavy Were the Tracks?

Variation in snow conditions and glide between different training sessions and races is one of the main reasons we strongly promote power measurement for intensity control in cross-country skiing. This winter there has been much discussion about the Swedish waxing team and whether they always managed to give the national team athletes the best possible skis. Recently, Johan Olsson wrote an insightful post on Instagram about how systematically the waxing team works with the athletes to optimize glide — and how incredibly small the margins are between good and less good skis.

For us ordinary recreational skiers, the margins are far greater, and it is often the external conditions that become our biggest opponent when we chase personal bests. This has been especially obvious during this year’s Vasaloppet week. On Friday, February 21, Vasaloppet-30 was held in surprisingly perfect conditions despite the lack of natural snow — resulting in record times. The next day, the weather gods were far less kind to the women racing Tjejvasan. And just one day later, during Öppet Spår, skiers again enjoyed clear skies and fast, icy tracks where many personal records were set.

Everyone agrees that you cannot compare times between races with completely different snow conditions — yet we all lack proper tools to evaluate how a performance in good conditions compares to one in poor conditions. To make any meaningful time comparison, we must first quantify the difference in glide. Scientifically, glide is expressed as glide friction, the ratio between braking force and skier weight. This is where the Skisens power grips become incredibly valuable.

I was one of the lucky skiers racing Vasaloppet-30 on Friday — naturally using the Skisens power grips, which recorded the forward-directed force I generated. Skisens also measures speed and gradient using GPS and a barometer, giving us the unique ability to calculate glide friction. My measured glide friction for Vasaloppet-30 was 0.023, which corresponds to extremely fast winter conditions — roughly equivalent to standard #2 roller skis.

The following day, during Tjejvasan, I sat inside a cabin in Orsa Grönklitt watching the race on TV as both organizers and competitors struggled through heavy snowfall and wet snow. It was obvious early on that the winning time would be much slower than Kortvasan the day before.

Unfortunately, we had no athlete using Skisens grips during Tjejvasan, so we do not have any measured friction data from the race. But I attempted an analysis based on a training session I did right after Britta Johansson Norgren’s well-deserved victory. Despite heavy rain, I skied 24 km in Orsa Grönklitt’s usually excellent — but on this day very wet — tracks.

By coincidence, those 24 km took exactly the same time to complete as Vasaloppet-30 the day before: just under 1:32. Reviewing the data later, I found that my average power had actually been higher in the rain (160 watts) compared to the day before (140 watts). The glide friction I measured in Orsa was 0.042 — compared to 0.023 on Friday — meaning that ignoring air resistance, the snow was almost twice as slow!

Orsa Grönklitt sits at higher elevation and naturally has different snow conditions compared to the track between Oxberg and Mora. Still, both areas experienced rain. The tracks between Oxberg and Mora may have been icier. Also — unlike elite skiers — I did not spend hours optimizing my grip and glide. For the sake of this analysis, let us assume that the glide friction for well-prepped skis in Tjejvasan was around 0.035. The key question becomes:

1. How much higher average power would I have needed to ski Tjejvasan 2020 in the same time as Vasaloppet-30?

With a glide friction of 0.035, I would have needed to sustain an average power of 192 watts (2.56 W/kg) to maintain 19.9 km/h.

2. What time would I have achieved in Tjejvasan if I held the same average power as in Vasaloppet-30?

With friction 0.035, sustaining 1.9 W/kg results in an average speed of about 16.5 km/h — corresponding to roughly 1 hour and 49 minutes.

3. What average power did Britta Johansson Norgren likely produce in Tjejvasan — and what would that correspond to in Vasaloppet-30?

Our friction estimate suggests Britta held approximately 3.0 W/kg. Converted to Vasaloppet-30 conditions (friction 0.023), this corresponds to a time around 1:13:30 on my skis. If her skis had ~10% better glide (friction 0.020), her equivalent time would be about 1:11:30.

These numbers require assumptions — especially since we did not measure friction directly in Tjejvasan. But the results are reasonable when compared to the fastest Kortvasan skiers. For example, Johan Kanto (IK Stern) skied Kortvasan in 1:11:30.

For all the women who battled through Tjejvasan’s brutal conditions, we now present a table translating your Tjejvasan time into what it likely would have been under the near-perfect conditions of Vasaloppet-30 and Öppet Spår.

A table like this should naturally be taken with a grain of salt. Even though we tried to make the analysis as scientific as possible, many factors remain — especially the mental toughness required to hold high power output in bad weather. This likely affects recreational skiers far more than elite athletes.

Next year we hope to have several athletes racing Tjejvasan with Skisens grips — then we will know the real glide friction!

/Dan