Guro Ström Solli is himself an old World Cup skier who has been able to follow Marit Björgen's successes up close.
She is now employed as a researcher at Nord University in Norway and has gained full access to Björgen's exercise diaries.
She has also done between five and ten interviews with the world star.
On Thursday, Solli defended her doctoral dissertation on why Björgen is the most successful Winter Olympics of all time.
- Marit had continuity in training.
She had setbacks, but always continuity in training.
She kept herself injury-free and for 18 years she trained an average of 15 hours per week, says Solli to Norwegian VG.
"Wow factor is continuity"
Some of the factors behind Björgen's enormous success are an active childhood with a lot of play and outdoor activities, that she tried several different sports until she was 18 years old and that she gradually increased her training up to 940 hours a year when she trained the most.
- There are no big wow factors or secrets in the training itself.
The big wow factor is continuity.
Marit trained mostly between the ages of 30 and 35, says Solli and continues:
- She has done 14,000 training hours in 18 years and traveled a distance equivalent to Norway around one and a half times.
That's respect.
Will compete in the Vasaloppet
The interest in the publication - "The development process of the most successful Winter Olympian in history" - has been great.
- It's fun that many people have noticed it.
Marit was a unique athlete and not many people have shared as much of their training, says Solli.
Björgen, who put the skis on the shelf two years ago, decided this spring to compete in the Vasaloppet 2021.
ARCHIVE: The sensation: Björgen makes a comeback in the Vasaloppet (26 May 2020)
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Marit Björgen in the brothers Auklands Team Ragde Eiendom.
Photo: NRK / BILDBYRÅN