At the 1983 World Championships she finished fifth in her 400 m semifinal and was eliminated, but won another gold medal in the relay, with teammates Gesine Walther, Koch and Rübsam.

Busch switched to the 400 m hurdles in 1985, with immediate success, winning the European Cup in Moscow in 54.13 secs, before breaking Margarita Ponomaryova's world record of 53.58, with 53.55 in Berlin in September.

Busch began 1986 by winning the 400 m title at the European Indoor Championships for the second time, having also won the 1985 Event.

At the 1988 Olympic Games in Seoul she finished fourth in the final of the 400 m hurdles, being edged out of the bronze medal by her GDR teammate Ellen Fiedler (53.63 – 53.69).

In 1991, Busch represented a United Germany at the World Championships in Tokyo, where she was eliminated in the semi-finals in 55.93 secs.