A short description in English for "non Swedish speaking" visitors to this site:

Friskis&Svettis is a non-profit chain of fitness clubs developed in Sweden. There are 109 clubs in Sweden, 35 in Norway and 10 in other European countries. We offer training for all ages based on science and experience.

Friskis&Svettis in Trosa is one of these independent clubs having about 500 members.

Trosa is a small city as well as a community with a population of about 11 000 located 70 km south of Stockholm.

Some English-language links... 

Friskis&Svettis Riks, the head organization  
      (go to "English summary")

Friskis&Svettis, Amsterdam