Freestyle swimmer Detlev Grabs first appeared internationally at the 1977 European Championships when the East German 4x200 freestyle relay won the bronze medal. At the 1978 Worlds, the relay squad then came sixth. In 1979 he won the East German national title over 200 and 400 freestyle. At the 1980 Moskva Olympics, which were boycotted by the Western countries, Grabs won silver in the 4x200 freestyle relay. In the individual 200 and 400 freestyle events, he was eliminated in the heats.
Grabs then studied medicine at the Berlin Humboldt University and became assistant physician at the Anatomic Institute. In 1997 he moved to Fribourg in Switzerland, and in 2007 to the University of Québec in Canada, where he was named professor.