Curiously, every single soviet sports athlete who ever competed on any international event was considered an amateur, while in fact being a full time professional devoted to his sport.
Usually they were officially 'working' at some factory, but were members of a sports club and received a substantial stipend, never doing any work but training and competing. This practice still lives in Russia. The income of any Olympics team russian athlete is estimated to be no less than 5-7k USD, generally coming in the form of several grants and stipends.