Survivors of this year’s Tour de France are to ride into Paris today after racing 2,131 miles over 23 days, including daunting climbs through the Pyrenees and the Alps. For the first time in years, evidence suggests that doping may not be playing the dominant role it once did.
More than any other sport, bicycling has been linked to drugs. Podium finishers in nearly every Tour over at least the last two decades have failed drug tests, admitted to doping or been linked to high-profile investigations.
Viewers have tended to regard the winners with a bit of disbelief.
But the sport appears to have turned the corner and is regaining some credibility, thanks to the antidoping efforts of a new generation of riders, managers and fans. There is, as yet, no conclusive proof of this, as one cannot prove a negative. Still, we now believe that cycling is cleaner than it has been at any time since 1990.
Three years ago, cycling introduced one of the most aggressive and progressive antidoping strategies in sports: the biological passport. It aims to detect the underlying markers of doping rather than the doping products themselves, and is based on the principle that red blood cells, which carry oxygen to muscles to help power cyclists up mountain passes, behave in a predictable manner. Any deviation from this predictable pattern raises a flag and suggests practices like the injection of EPO, a naturally produced hormone that promotes the formation of oxygen-carrying red blood cells, or blood doping, the transfusing of one’s own blood back into the body before or during a race. Both practices produce fluctuations in key measures that track red blood cell function.
The passport is onerous for cyclists, who must account for their whereabouts and be available for regular testing throughout the year, and expensive for the sport. But it appears to have led to real change. Some battles are still being lost — a Russian rider was forced out of this year’s Tour after a blood test — but the war on doping is slowly being won.
Most telling has been the noticeable slowing down in performances in the crucial mountain stages. Taken in isolation, a single performance tells little about the state of doping — there are simply too many factors, like wind, race situation, rider preparation and injury, that influence performance to prove that the sport is cleaner based on one climb alone. But the trend toward slower performances has, to date, been universal, so much so that the finishing climbs in the 2010 and 2011 Tours de France have been substantially slower than those of the 1990s and the 2000s, some by many minutes.
For example, the fastest riders on three of the last climbs in the Tour, including the famed Alpe d’Huez, were still three minutes slower — a lifetime in cycling — than many of the fastest riders on the same climbs during the 1990s and 2000s.
Linked to this are the physiological aspects of performance. In the same way that a motor vehicle requires certain components to travel at 200 m.p.h. — a huge engine, fuel and aerodynamics — a cyclist requires certain physiological characteristics to produce the power output necessary to win the Tour de France. Those characteristics, which include a high maximal capacity to use oxygen and efficiency of converting metabolic energy into power, are identifiable and measurable.
It is possible to use these physiological characteristics to estimate the maximal sustainable power output for a cyclist. It requires some assumptions, but if they are consistent and made in favor of the cyclist, then they reveal that in the 1990s and 2000s, Tour performances routinely exceeded the predicted physiological capacity of humans. In contrast, 2010 and 2011 Tour riders have been beneath this ceiling on every climb of the race. The slowing in times thus brings physiology back in line with what are believed to be limits of performance.
Together, the climbing performances and physiological implications set up the compelling hypothesis that the Tour has returned to the days before 1989, when EPO became available. Until about a decade ago, athletes were able to use the drug with impunity, as there was no reliable test for it. Evidence has revealed that after the test was introduced, athletes simply adopted blood doping to achieve the same performance-enhancing effects.
Since 2008, however, the biological passport has made it increasingly difficult for athletes to use both of these techniques, and the result is that the proportion of suspicious blood samples has drastically fallen. Cyclists may still be doping, but their methods have been changed and then reduced to the point where they are using much smaller doses that have a concomitant effect on performance.
So if this year’s cyclists seem to be speeding over the French mountains at a slower pace, it could well be because they aren’t doping — or are doping less than past competitors have. Doping will always exist, as it does in every other sport, but cycling just might be restoring its credibility, one pedal stroke at a time.
Ross Tucker and Jonathan Dugas, exercise physiologists and founders of the Web site The Science of Sport