"I'm convinced that we have a doping-free environment," claims sports chief Bjørnar Håkensmoen, who blames the positive doping results of some foreign competitors for hurting the Norwegian athletes' credibility.

"It's too bad, because credibility is something we're very concerned about," Håkensmoen told newspaper Aftenposten.. He stresses that Norwegian athletes have never tested positive for doping, and that cross-country skiers have been tested 216 times just since last May.

Suspicions remain, and it's just something the athletes have to live with. They take precautions to avoid being sabotaged, never leaving their water bottles unattended, for example, and controlling what they eat.

A public opinion poll conducted by research firm Opinion for newspaper Aftenposten shows that 18 percent of those questioned think doping exists nonetheless, among athletes involved in World Cup skiing. Some Norwegian athletes in other sports have tested positive, and that also affects the entire sports spectrum, Håkensmoen concedes.

Marit Bjørgen, Norway's best female skier at present and a medal favorite at this week's World Championships in Oberstdorf, understands that people can begin to wonder when athletes like her perform so well.

"There are some who ask where all my muscles have come from," she says. "Sometimes there's suspicion behind the questions."

Where did the muscles come from?

"In part, I'm born with them, inherited from my mom and dad, and I've worked a lot in the barn on our farm, and I've worked out," she told Aftenposten.