Performance-enhancing drugs continue to cast doubt on too many outstanding athletic performances.

An arbitration panel’s decision to uphold drug test results that will strip Floyd Landis of his Tour de France crown is yet another blow to the reputation of international sports.

Continued allegations, suspicions and punishments associated with the use of performance-enhancing drugs are having a devastating effect on the sports world. Spectators and supporters can’t help but grow disenchanted with athletic competitions that increasingly seem to be influenced by the use of dangerous artificial substances.

Not only the athletes, but the drug testing to which they are subjected are under suspicion. The panel considering Landis’ case conceded that the initial test to measure the athlete’s testosterone levels was not done according to the World Anti-Doping Agency rules. The panel based its decision to punish Landis on a second, more precise test, but the first test still adds an element of doubt to the decision.

Landis and his attorneys clearly thought there was enough doubt to be worth pursuing this case, and may continue their fight with an appeal to the Court of Arbitration for Sport. Is Landis a victim of an imprecise testing system or someone who got caught and is trying to take advantage of testing flaws to beat the rap?

It’s hard to tell, which is frustrating and demoralizing for sports fans.

Over the years, too many great sports triumphs have been tarnished by later allegations or punishments for the use of illegal performance-enhancing drugs. Accomplishments that were celebrated as combinations of hard work and God-given talent have lost much of their sparkle.

Some observers will argue that the use of performance-enhancing drugs is no worse than other extreme training efforts athletes make to perfect their performance. But athletes shouldn’t have to use drugs that can injure their long-term health in order to compete on an equal footing.

The first step, of course, is to work on drug testing to make it as consistent and accurate as possible. Fewer loopholes will mean fewer opportunities for athletes to avoid detection and punishment. Reliable tests will make rigorous enforcement possible.

It’s sad for any sports spectator to have to wonder whether an outstanding athletic performance was made possible only through the use of “dope.” It’s even sadder for athletes to feel they must subject their bodies to such treatment in order to compete at the highest levels.