In the new SVT documentary "Oski - an Olympic skateboard saga", 25-year-old Oskar Rozenberg Hallberg, Sweden's first skateboard Olympics and double world champion, talks about the problems he encountered when he started skating as a young man.

Because at his school in Malmö he stood out.

- I do not know if you call it bullying, I was teased sometimes.

I was the least in the class, and I was the only one at school who skated.

So people started calling me a skate nerd.

You did not feel safe, you knew you could be teased at any time, the teachers did not do much about it either.

I think children tease each other just for not being the one who gets teased, says Oskar Rozenberg Hallberg in the SVT documentary.

"Understood it was psychosomatic"

He was between eleven and twelve years old when it happened.

Without any major support from the teachers, but one hundred percent from the parents.

- I do not know if he felt bullied, but on the border anyway.

I went to pick him up as many times as I could at school, and the last one he had spat.

Then I understood that it was psychosomatic.

So then I thought we might have to change schools.

It was a bit of a rescue for Oskar, in fact, explains Oskar's father Johnny Hallberg.

Watch "Oski - an Olympic skateboard saga" on SVT Play.