The Academic Sports Association Zurich (ASVZ) runs four different sports centers and offers instructional classes in over 70 different types of sports, recreation and wellness, as well as various drop-in facilities such as solariums, saunas and weight rooms.
The entire program is in English, therefore you do not need to know German. However, some basic German can help in everyday life and you might want to take the chance to learn it.
Learning German by listening to the locals is not easy, because the local Swiss German dialect can be hard to understand, even for Germans. However, most locals are so kind to switch to proper German or English if they notice that you have problems understanding their dialect.
Since there are many non-German speaking foreigners as well as Italian and French speaking Swiss in Zurich and with its two academic institutions, attending a language course is a common thing to do.
Courses are offered by the Language Center (Sprachenzentrum) of the University and the ETH Zurich.