Dick Pound is a frequent critic of cycling's poor drug record.

Dick Pound, head of the World Anti-Doping Agency (WADA), said Thursday that Floyd Landis's positive test proves cycling has a long way to go in restoring its shattered credibility.

Pound, a frequent critic of the sport's drug record, said cycling will take a severe hit if the American's backup B sample confirms the positive test of the male hormone testosterone.

"When is this going to end? What is the UCI [International Cycling Union] going to do about it?" ask Pound, referring to the sport's world governing body.

Pound is also amazed Landis would risk doping allegations during the Tour de France following the pre-race scandal that led to the dismissal of nine riders, implicated in a Spanish doping probe.

"It's always disappointing when you see something like this," Pound told The Associated Press by telephone from Montreal.

"If there is a positive test, what have you got? The guys who came second, third, fourth, fifth and sixth at last year's event have been busted in the [Spanish investigation], and now the winner of this year's event is busted in the race itself."

Landis's Tour victory against long oddshad been considered a lift for the sport amid recent scandals.

The 30-year-old former mountain biker waited three years for this opportunity while riding in support of seven-time champion Lance Armstrong.

Landis, who rode with an arthritic hip, made one of the greatest comebacks in the history of the Tour to win the event.

"You build up and create a new hero, and he gets slapped down," said Pound. "It's a serious blow."

However, Pound said the sport has an opportunity to finally clean itself up.

"It's one of those half-empty, half-full things," he said. "Either it's the worst day in your life. Or it's the worst day in your life, and you say, 'From now, I'm climbing out of the hole and this is what I'm going to do, and we're going to win your confidence back that our sport is clean.'"

If not, Pound sees the sport falling into a deeper hole.

"If they don't do it, there will be a downward spiral from which it would be very hard to recover," said Pound. "If they're not seen to do anything effective after all of this, then they really, really have a problem."

Pound said WADA will only observe the Landis situation.

If the American's B sample comes back positive, Pound said the UCI would probably send the case to the U.S. Anti-Doping Agency.

Pound is confident in the urine test for testosterone, which measures the ratio of the male hormone to epitestosterone.

A positive test is confirmed when the ratio rises above 4:1, prompting an inquiry to determine if outside factors could be involved.

The threshold was recently reduced from 6:1.

Landis's sample was examined at the French national anti-doping laboratory of Chatenay-Malabry.

"I'm confident that the rule is the rule," said Pound. "The test has been around for a long time. One assumes in an accredited lab it's properly done."