Gertrud has PhDs in history and sociology. From 1980 to 2000, she was employed as professor at the University Berlin and was appointed to a professor position at the University of Copenhagen in 2001. She received two honorary doctorates.
Gertrud has conducted several large national and international research projects; she has published more than 200 articles and 20 books. She was president of the International Society for the History of Sport (1989 to 2001) and head of the International Sport Sociology Association (2004 to 2008). Currently, Gertrud is member of the executive board in Women Sport International. All her life, Gertrud has been active in sport, in particular in skiing, tennis and long distance running.