You can register for the university sports courses via the Stud.IP group "Hochschulsport PH Heidelberg". There you can always register for the courses of the following week from Friday evening (18:00) and find the entire university sports programme. This means that you don't register for the whole semester, but only for one date at a time. This allows you to plan spontaneously and try out different programmes... why not give it a try now!