She is a 6-time Canadian Champion, represented Canada twice at the Olympics (2004, winning a silver medal, and 2008), a Commonwealth Games gold medalist, and from 2004 to 2008 was a regular medal winner on the UCI Mountain Bike World Cup cross country circuit.

She won three silver medals in the 2004 World Cup Circuit in Mont-Sainte-Anne, Quebec,[8] Fort William, Scotland[9] and Livigno, Italy.

[10] She won two gold medals in the 2005 World Cup circuit in Spa Francorchamps, Belgium[11] and Mont-Sainte-Anne, Quebec.

At Mont-Sainte-Anne in the 5th race of 2009, Marie was the victim of a flat and a fork lockout problem that resulted in a 10th-place finish, and a 13th place in XCO#6 at Bromont after some breathing difficulties limited her climbing ability.

There were podium finishes with a 4th at Offenburg[30] and a silver medal in a tightly contested battle at Windham, NY.

On 27 February 2013, she announced that she would be taking a sabbatical from mountain bike racing as she was pregnant with her first child.