[1] Haase trained with methods developed by Arthur Lydiard, the New Zealand trainer who was, at the time, still relatively unknown in Europe and was the surprise winner of the 1965 GDR 10,000 metres.

This episode became something of a political scandal, in the course of which Haase was pardoned by the GDR Sports authorities.

[1][2] Haase missed the 1972 Summer Olympics due to blood poisoning that he received after being injured by the spike of another runner at a competition in Paris.

After retiring from competitions in 1973, Haase was active in customer service and marketing of medical technology.

After the reunification of Germany, Haase worked at the Deutschen Leichtathletik-Verbandes (German Track Federation).