- I played football, ice hockey and tennis when I was younger.

I also played ice hockey at a fairly high level.

But I quit at the age of 13.

It became a bit too much with both tennis, ice hockey and school, he says.

There will be some rounds of golf with friends in the summers.

Otherwise, it is basically just tennis on the schedule for Måns Dahlberg. 

SVT Sport is taking part in one of two training sessions on the tennis court for the day.

On the other side is the Dane of the same age, Elmer Möller, who is also ranked among the best in the world at his age.

Even for an untrained tennis eye, it is not difficult to see that the level is high.

- Most sessions are quite intense, I would say.

But then if you have any feeling or you can reduce the intensity a bit, says Måns Dahlberg.

When he is not away and competing, in addition to the two tennis sessions, there is a physiotherapy session every day.

Top 15 in the world in his age

Måns Dahlberg is a typical example of what the modern road to the top looks like.

The venture took off in earnest when he himself contacted the tennis academy Good to Great five years ago.

Two years ago, he started training at the level he does now.

- It was a pretty obvious choice for me who wanted to do this more seriously.

So far, the investment has borne fruit.

Måns Dahlberg turns 18 this year and at the time of writing is ranked 15th in the world in his age.

He commutes between his parents' home in Gothenburg and the tennis academy's state-of-the-art arena in Danderyd.

The biggest Swedish talents and some foreign players come there in some cases already at the age of 12 and train in tailor-made programs.

The researchers: An increased risk of injury

Måns Dahlberg himself is not worried about the increased risk of injury that researchers warn that an early and specialized investment may entail.

- Of course it might be so if you just play tennis all the time.

If you are not doing any physique or doing rehab training as well.

I do not think it is so dangerous if you just focus on keeping your body in shape when you exercise.

See the full report on the conditions for double sports here: