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Ten Dam questions effectiveness of biological passport after Denifl, Preidler confessions

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Laurens ten Dam (CCC Team)

Laurens ten Dam (CCC Team)
(Image credit: CCC Team)
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Laurens ten Dam will spend his 18th year in the professional peloton with the new CCC Team

Laurens ten Dam will spend his 18th year in the professional peloton with the new CCC Team
(Image credit: Bettini Photo)
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Laurens ten Dam (Sunweb) marked the breakaway

Laurens ten Dam (Sunweb) marked the breakaway
(Image credit: Tim de Waele/TDWSport.com)
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Laurens ten Dam and Lukasz Winiowski

Laurens ten Dam and Lukasz Winiowski
(Image credit: Tim de Waele/Getty Images Sport)
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Georg Preidler (Groupama-FDJ)

Georg Preidler (Groupama-FDJ)
(Image credit: Bettini Photo)
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Sunweb's Tom Dumoulin and Laurens ten Dam lead a training ride

Sunweb's Tom Dumoulin and Laurens ten Dam lead a training ride
(Image credit: Tim de Waele/TDWSport.com)

Laurens ten Dam has called into question the effectiveness of the Athlete Biological Passport after Austrian riders Stefan Denifl and Georg Preidler admitted to blood doping earlier this week. Ten Dam expressed his surprise that the two riders had been able to avoid detection by the biological passport and asked, “is it as leaky as a basket?”

Denifl and Preidler were questioned by the police following a lengthy investigation into German sports doctor Mark Schmidt. Some 40 blood bags were discovered in a garage while five athletes were arrested at the Nordic Ski World Championships, one while infusing blood into his arm before a race. The police investigation is called Operation Aderlass - Operation Blood Letting. 

Cycling first introduced the biological passport in 2008 as a way of monitoring riders' blood values over time and detecting manipulation and the effects of doping that cannot be spotted by a traditional anti-doping test. However a number of riders have overturned possible bans on appeal, including most recently Burgos BH rider Ibai Salas, reportedly making the authorities cautious about starting legal battles. 

There have been suggestions that riders can use altitude training, illness and travel to justify variations in their Biological Passport levels.  

"I am amazed by the fact that a large blood doping network has to be discovered by the police and the judiciary. And it makes me suspicious. I want answers,” Ten Dam wrote in a column for the Het Nieuwsblad paper.

“Is the blood passport really that bad? Is it as leaky as a basket? Why had Preidler not been caught by the doping authorities and which names are we to expect from that 40 blood-bagged freezer? Many questions, few answers, I fear."

Ten Dam is a former teammate of Preidler, racing with the Austrian at Team Sunweb between 2016 and 2017. The pair were part of the team that helped Tom Dumoulin to victory at the 2017 Giro d’Italia. Ten Dam, who has previously ridden for Rabobank, said that he had been here before with teammates admitting to doping but that this one stung more than most.

"I have not thought of anything else for three days. Anger, but also distrust, I've struggle for focus during my training rides," wrote Ten Dam. "I have been in a team with several doping sinners, but why does this really catch me at the throat? An explanation: I am furious at Preidler.

“As a road captain during the Giro d'Italia in 2017, I had to have several 'firm' conversations with him. He wanted to go home because his girlfriend had a bloody nose. He ruined the atmosphere in the team while we were busy with something beautiful and unique: the Giro win."

Ten Dam is not the only teammate of Preidler to express his anger at the situation with Groupama-FDJ’s Thibaut Pinot calling it "high-treason" in an emotional interview with L'Equipe.