Wednesday, July 8, 2009

Lance Armstrong

It is currently my intention that this is going to be a cycling blog, mostly related to pro cycling. I think it is customary to first address every cycling fan's primary question: what do I think about Lance Armstrong? Why, thanks for asking.

I don't particularly like or dislike Lance Armstrong. I have been following cycling closely since 2000, when I started racing with some friends. The crowd I rode with were somewhat ambivalent about Armstrong. They appreciated his Tour successes but as members of a somewhat snobbish niche community they tended to maintain their loyalties to the European stars who were unknown in the United States (Pantani, Jalabert, etc). My personal favorites have been attackers who make races exciting, like Jens Voigt and Ludo Dierckxsens. Armstrong's Tour years were long stretches of predictability punctuated by the occasional fireworks. So I guess he's ok.

I've never been especially bothered by pros who dope. I'm amused to see cheaters get caught, but I've never seen any reason to get angry about something as inconsequential as a pro bike race. However, since I work in biotech and race on the weekends, I am interested in what's behind pro performances. I'm particularly curious about the balance between genetic and therapeutic contributions to a racer's success and, in this respect, there is no greater curiosity than Mr Lance Armstrong.

Armstrong's Personality

Before I get into the doping issues, let me state that everything I've read and seen about Lance Armstrong suggests he is a jerk. He's an ass to his competition and a prick to anyone who criticizes him. But he's a hell of a bike racer. The quintessential Armstrong race was the famous "no gifts" Stage 17 of the 2004 Tour de France into Le Grand Bornand. He used his highly paid (and probably doped) teammates to fragment the field and chase down the struggling break. He offered a half-assed effort to help a teammate win the stage, but when that looked unlikely he unleashed a perfectly-timed, ferocious sprint to chase down and beat Andreas Kloeden, an accomplished rider who had never won a Tour stage. It was an incredible performance, and one motivated by his desire to punish German fans for their crude behavior against him the previous day (Kloeden was riding in the German national champion's jersey). Armstrong's tender sensibilities were further exhibited in a post-race interview, when he explained that he had "given gifts in the Tour de France and very rarely has it ever come back to help [him]." This prickly egoism can be hard to take from a guy who is dominating the Tour for the sixth time. But that was one of the most exciting finishes I've ever seen, so at the end of the day I don't really mind Armstrong's comments or his motivation. It was a great bike race.

Many contrarian types also criticize Armstrong for his personal life and his LiveStrong organization, but I'm not interested in Armstrong's personality or hero status here. He's just a guy who rides a bike fast.

Armstrong's Genetics

It has been said that Armstrong’s physiology is maybe above average for an athlete but nothing beyond past Tour champions. According to the blood test values he has recently released, his level of success wasn’t due to a naturally astronomical hematocrit that let him race above 50%. Neither was it his V02 max, which reportedly peaked around 82-84 ml/kg/min – elite but below Indurain and Lemond’s values of 88 and 92.5 ml/kg/min, respectively. The one extraordinary number that constantly appears in discussions of Armstrong’s physiology is his low lactic acid production. It has been reported that during anaerobic efforts his lactic acid production is one-third to one-half the normal rate. Since lactic acid is thought to cause muscle pain and fatigue during intense efforts, it is often stated that Armstrong’s advantage is that he does not feel the pain that others do and he can therefore push harder. That sounds reasonable, but I wonder if there is more to it than that. Lactic acid is not primarily a fatigue-signaling molecule; it is an irritating waste product of fermentation and accumulates during anaerobic conditions. So if Armstrong’s muscles either do not producing lactic acid at a normal rate or somehow remove lactic acid during anaerobic efforts, his metabolism must be abnormal. So Lance Armstrong might have a genetic metabolic disorder that allows his muscles to strangely create lots of energy around lactate threshold. This is pure speculation -- the type of speculation that a geneticist engages in when considering a seven-time Tour winner, because a geneticist is fascinated by freaks of nature.

Armstrong's Therapeutics

There have literally been books written about whether Lance Armstrong doped his way to seven Tour victories. Since there is plenty of evidence that his competition doped, a common Armstrong defense is that the playing field was level. That is a reasonable position if you're willing to concede that he doped, but just makes the question all the more fascinating to me: was Armstrong clean when he beat them?

David Walsh certainly doesn't think so. He has made a career of making doping allegations against Armstrong. He has a mountain of circumstantial evidence but has never produced anything I find conclusive. While I'm convinced that there was doping on US Postal, most of the strong evidence I've read addresses the pre-Armstrong years or Armstrong's teammates.

There is some evidence that Armstrong used synthetic EPO based on his hematocrit readings. According to a
Bicycling article about Dr Michele Ferrari, Armstrong was recorded to have a maximum hematocrit of 47%. It's not clear to me when these values were taken; it might have been prior to Armstrong's cancer. Recently released data on Armstrong's current (2009) blood values show a maximum hematocrit of 43%. I don't know if this sort of variation can be achieved without doping, but it does suggest that Armstrong rode with a higher than natural hematocrit. However, to Armstrong's credit, the same article mentions that US Postal teammate and fellow Ferrari client Kevin Livingston's hematocrit was 49.9%, just below the UCI limit of 50%. If Ferrari was also doping Armstrong, why would he max out at 47%?

The real proof of Armstrong's doping would be a failed drug test, but unfortunately the major positive result is mired in uncertainty. In 2005, synthetic EPO was found in at least six of Armstrong's blood samples from the 1999 Tour. This finding was described in detail in an interview with
Dr Michael Ashenden on Velocity Nation. A group of researchers was trying to develop detection methods for synthetic EPO in athlete's urine. They needed a training set for the tests; that is, a group of blood samples in which some were known to have synthetic EPO. They chose Tour de France samples from 1999. It isn't clear to me why they didn't use medical samples from anemia patients who had definitely been treated with synthetic EPO. Instead they made the assumption that there must have been doping during the 1999 Tour and thus there would be positives. From a scientific standpoint, this is a very questionable study design. A positive control should, by definition, consist of fully specified and characterized samples, not mysterious samples paired with the assumption of guilty athletes. It is obvious that if you are tuning your test until you recover a positive result (which is what you do with a positive control) you will get a positive result. Without a proper positive control, there really isn't any way to determine if the test was properly tuned. This makes the study findings very difficult to interpret. However, one might argue that if the analysis was producing random noise, it is very unlikely that so many of Armstrong's samples (6 out of 15) would test positive. This compares to 13 positives in a total of 87 samples, and according to my math the likelihood that Armstrong would have so many positives in random data is 1 in 120. So even if the study was poorly designed, over a third of Armstrong's samples were positive whereas only 10% of the other samples were. That is a pretty powerful argument and I'm almost convinced. However, Ashenden then overplays his hand by claiming that the only possibilities are that Armstrong doped or the samples were deliberately tainted by laboratory personnel. But this just begs the question of having a controlled experiment; Ashenden shouldn't rule out other possibilities because the researchers weren't controlling for other, possibly unknown, variables that might be correlated with Armstrong's samples. So while these arguments support the hypothesis that Armstrong doped in the 1999 Tour, I don't think this hypothesis has been validated to scientific or legal standards.

As a minor point, Ashenden claims it was impossible for the labs to know whose samples they were testing. Given the UCI and French anti-doping lab's long history of leaking doping positives to L'Equipe, I am not convinced that the information barriers Ashenden claims exist between these entities are always respected. So I do not share his complete trust in the competence and ethics of these labs.

Nevertheless, the study is the best Armstrong-related doping evidence and Ashenden deserves credit for taking the effort to explain it. Unfortunately Ashenden and his interviewer Andy Shen don't stop there. Shen bizarrely asserts that Armstrong is far shorter than advertised, and stands only 5'5" or 5'6" tall. Ashenden later claims Armstrong weighed over 74 kg (163 lbs) when he was winning the Tour. This data corresponds to a BMI of at least 26. This is officially considered "overweight" by the NIH. I understand the NIH standards apply poorly to muscular builds, but pro bike racers are built like the skeletons of ballerinas. I am 6'1" and 158 lbs (BMI 21) and look like a gluttonous hulk when standing next to one of our local pros. So I am supposed to believe that Lance Armstrong won the world's hardest bike race with a BMI of 26, and furthermore that this means I should question Armstrong's credibility? This is not terribly convincing. In fact, it is extremely weird.

Speculation on Armstrong's weight is primarily introduced to make the case that his post-cancer transformation into a grand tour champion was a result of doping. This is speculative ground, but relevant in light of a common counter-argument based on a study by Ed Coyle. The Coyle study claimed novel physiological changes brought about by Armstrong's specialized training enabled him to transition from a single-day racer to a grand tour winner. I think Ashenden convincingly refutes most of this study, allowing the possibility for other theories. Ashenden's personal theory is that Armstrong doped. It essentially comes down to the contention that Armstrong lied about his weight (of course he did; every professional athlete lies about their weight). Ashenden is particularly keen to show that Armstrong's post-cancer weight loss was a lie (and an illusion for those of us who have seen pre- and post-cancer video footage). He tries to refute Armstrong's claim that he weighted 72 kg during his Tour wins by quoting Coyle's measurement of 79 kilograms for Armstrong's weight in November 1999. According to Ashenden, Armstrong wouldn't allow himself to gain so much weight between races, so clearly Armstrong was not as low as 72 kg during the Tour in July. This is neither a evidence-based nor convincing assertion. November is the heart of the off-season for a cyclist who concentrates on July, and it is not unheard of for pro (and amateur) cyclists to gain significant weight during the fall and burn it off during daily 5-hour training rides in the winter and spring. Ashenden then asserts that because Armstrong admitted under oath to a race weight of 74 kg, he really must have weighed more than that. There is no evidence to support this hunch. I think the best one can say here is that we don't know how much Armstrong actually weighed, at any time during his career. Which means one can't draw any conclusions about how big a role weight loss played in Armstrong's Tour success.

Ashenden also uses Tour de France time trial results to measure Armstrong's pre and post cancer performance gains. I think it is common knowledge that riders without an interest in the overall classification of a grand tour often do not put a full effort into the time trial stages. These riders lose hours over the mountains stages; losing ten more minutes in the time trials is nothing if one can save their energy for a chance at a stage win down the road. Before cancer Armstrong was riding for stage wins and after cancer he was riding for the overall, so judging his differences in fitness by time trials is inconclusive and kind of silly.

Finally, my greatest objection to the argument that doping transformed Armstrong into a Tour winner is that it implies pre-cancer Armstrong was a clean, or at least cleaner, racer (otherwise he would have won the Tour earlier). Personally I think this is highly dubious. Armstrong was the number one ranked cyclist in the world at age 21, in an era famous for rampant doping in pro cycling. He won the prestigious World Championships Road Race by riding away from a peloton of the world's best dopers to cross the line alone. Frankly, I would be shocked to learn Armstrong wasn't doping at that time. If Lance Armstrong was clean in 1993 then his cycling gifts are truly awesome, and I have no problem believing every one of his Tour wins were the product of a new post-cancer focus with no drugs involved. Alternatively, if he was doping prior to cancer, drugs alone won't explain the later Tour success. One could split hairs and make the argument that he was doping back then, but after cancer his doping practices were re-focused on the Tour and greatly intensified. Sure, maybe. But I don't see how you can make this argument with numbers, as per Ashenden; you are left with comparing one set of performance metrics clouded by the effects of doping with another set of performance metrics clouded by doping. One can only isolate the effects of doping by comparing a non-doped Armstrong with a doped Armstrong, and I'm not convinced anyone has this data.

So did he or didn't he?

If I had to make a call, I would ignorantly guess that Armstrong doped during his Tour victories. I'm still fascinated by the idea that he harbors a very rare and advantageous genetic makeup, but that just seems less probable. The best I can hope for is that he is able to contend for overall victory at this year's Tour and he continues to release his blood values while he does it. If he can win the Tour at age 37 with a hematocrit of 43%, he might just be the freak he claims he is.