She won the gold medal in the 4 x 6 km relay at the Biathlon World Championships 2004 in Oberhof, 2004.

Individually, she won the bronze medal at the 15 km of the Biathlon World Championship 2005 in Hochfilzen.

Grubben won the last race of the 2005-06 Biathlon World Cup in Oslo, capturing the third position in the overall rankings.

At the World Championships in Antholz-Anterselva, she collected bronze, silver and gold medals.

After winning her third medal which was a bronze at the 2007 World Championships, she announced her retirement from the sport.