It is sometimes said that elite sports are created by men for men.
Knowledge for research on menstruation in sports has been both neglected and de-prioritized.
But in recent times it has increased slightly.
Recently, the British tabloid The Telegraph published a report on Chelsea's women's team, which has become the first club team in the world to optimize training based on the hormonal fluctuations of the menstrual cycle.
But there is a lot to learn in the field.
Study in Norway
The majority of female biathletes and cross-country skiers in Norway now say in a study that they perform worse during menstruation.
This is shown by the research study done in the field at the Norwegian University of Science and Technology in Trondheim.
In the study, which is based on 140 elite athletes, 47 percent answered that they experience poorer physical shape during menstruation, just under a third think that performance is negatively affected.
Just over a quarter of these talk about it with their coach.
Part of the problem is that almost everyone (92 percent) lacks knowledge about exercise and the menstrual cycle.
- For me, there is nothing that is very surprising.
The coaches also have no knowledge of this.
If you have a degree or master's degree in sports, understanding about menstruation is a very small part of the education.
So the coaches usually have little knowledge and the practitioners themselves also have little knowledge, says Öyvind B. Sandbakk, one of the researchers behind the study, to SVT Sport.
"A system error"
Do you think it's taboo to talk about?
- My experience with Norwegian practitioners is that as soon as there is talk of menstruation, women are very open about it.
When we ask questions, taboos are removed very quickly.
My experience of this is that we must put it more clearly on the agenda and get the knowledge we have.
We also need to do more research on it.
Today, seven percent of sports research is focused on women.
- This is basically a system error.
How many female researchers do we have?
It's almost only men.
How many female sports leaders do we have?
90-95 percent are men.
How many female coaches do we have in biathlon and cross-country skiing?
It's the same there.
Sandbakk envisages that within a ten-year period there will be a greater understanding in the area.
- I think we can see fairly fast results in terms of results.
But it is also about changing a culture.
Time is required to make a total change.
I think we can see quite big differences in the dialogue between coaches and practitioners within a year or so.
Within ten years, we may also have changed the gender balance at both coach and leader level if sport wants this.
SEE MORE: The big team charts the period: "It should not be hush-hush"
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Magdalena Eriksson hopes that Chelsea's work can help remove the stigma surrounding menstruation and elite sports.
Photo: Bildbyrån