Track cyclist Klaus-Jürgen Grünke won the gold medal at the 1976 Montréal Olympics in the 1,000 metres time trial quite easily, almost 1.6 seconds ahead of the field. One year earlier he was also World Champion in this event. Domestically, Grünke won seven East German national titles (1,000 metres time trial: 1970-71, 1974; tandem: 1972-73; team pursuit: 1971, 1974). In 1974 he won the silver medal with the East German pursuit team at the Worlds, and in 1975 added a bronze medal in this event.
Grünke trained as a constructional steelworker, but later became a bus driver in Berlin after re-unification. His brothers Dieter and Peter were also successful cyclists on a national level.