A reconsideration of a famous Tour de France cyclist's physiology

Yep, the gossip circus surrounding Lance Armstrong is still alive and kicking. No, I am not going to tell you anymore Ophray Winfrey-like stories, we have heard enough of those.

Let's take a more positive (...) approach.

So. Unless you hate sports or have lived under a stone for the last few years, you haven't missed the ongoing doping scandal in road cycling. A few months ago, this reached a climax with the confession of seven-fold Tour de France Champion cyclist Lance Armstrong to have used erythropoietin ('epo'), red blood cell reinfusion, testosterone, cortisone and human growth hormone to enhance endurance performance.

Ever since, the big question is how much this doping has contributed to his great success, including his Tour de France victories? In other words, how good really is Armstrong? What makes him such an excellent athlete, doped or not?

Well, believe it or not, Lance Armstrong's physiological progress has been described in detail in a scientific paper published in the Journal of Applied Physiology in 2005. Researchers from the University of Texas have closely monitored Armstrong's maturation as an elite cyclist and found some interesting results that might answer the questions above.

Lance Armstrong was tested 5 times between 1992 and 1999. Body composition, maximal oxygen uptake, lactate treshold and mechanical efficiency were measured. Since Armstrong was diagnosed and treated for cancer in 1997, but still tested that year, this period of reduced training and recovery was incorporated into the measurements. Most tests were done off-season, though 1 test was done at the end of the race season (no athlete would come in for a scientific test in the middle of the race season).

In the race season of 1993, Lance's VO2max, i.e. the maximum amount of oxygen his body can take up per minute, was ~ 6 L/min. Or, since body mass determines oxygen uptake capacity,  around 80 ml/kg/min. The pre-season measurements were a bit lower, but still around 75 ml/kg/min. Given a strong reduction body weight from pre-season to race season, but an assumingly steady VO2max of 6L, Lance Armstrong's VO2max values during the Tours were estimated to be around 85 ml/kg/min. For comparison, Miguel Indurain, fivefold winner of the Tour, is reported to have values around 80 ml/kg/min.

Armstrong's lactate treshold was, as expected, at the high end of the range, with LT at 76-85% of VO2max. Most unique though, was the low lactate level after maximum effort. While others, including his teammates, had lactate levels of 9-14 mM after exercise, Lance's values were only 6.5-7.5mM. In other words, either lactate production was extremely low, or lactate removal extremely fast.

From Coyle, Journal of Applied Physiology 2005

Showing that he really is human after all, chemotherapy and the concomitant decrease in training volume affected his VO2max. Eight months after chemo, with a training load of about 1-2 hour at moderate intensity per day, VO2max was around 67 ml/kg/min and post-exercise lactate levels were 9.2mM. It must be noted that it is generally thought that people who are not somehow genetically endowed for endurance, can maximally reach 56-62 ml/kg/min - with prolonged and very intense training. In other words, Lance's values after chemo were still higher than the those of a hard training, but untalented, John Doe.

That's a nice bunch of data. What does it tell us about the maturation of such an extraordinary athlete?

Interestingly, VO2max and LT values did not change all that much during Lance's career. What did change, was his mechanical efficiency. Efficiency is the amount of work one can put out for a given amount of energy. It speaks for itself that it is beneficial if one can put out more work (watts) while using the same amount of energy. Well, Lance Armstrong's efficiency increased a mere 8% during his career. When incorporating the race season's weight loss, this increases to 18%.
That's a lot. Think of having to work 8-18% less to bike at the same speed.

What does this have to do with doping? The author of the 2005 paper has now published a reconsideration of their conclusions at that time (in Journal of Applied Physiology May 2013). Would the data have been affected by Lance's doping? Obviously it is hard to tell for sure which, if any, results have been skewed by doping. However, the substances Armstrong has admitted to have used are not known to have any effect on mechanic efficiency. Increased training capacity due to doping can help change lactate treshold and VO2max, but mechanical efficiency is thought to increase due to changes in the amount of slow muscle fibers. That is a long term process that is probably not that easy to change with doping.

In summary, Armstrong's physiological values are well, well above average. His VO2max is amongst the highest every recorded, his blood lactate values are extremely low. However, these values did not change all that much during his maturation as a cyclist. Most of all, his dedication to training has paid off in the form of a remarkable increase in mechanical efficiency.

So, yes, he has used performance-enhancing drugs. There is no excuse for that from many perspectives - as an athlete that is distorting competition, as a leader of his Foundation, as a person per se, even. No one can tell how he would have performed without doping - as we don't know for many in the peloton at that time. But whether you like Armstrong or not, his doping use, his personality or whatever, a big part of his progress can be attributed to a factor that is unlikely to be changed by doping, namely his mechanical efficiency. That makes him a very remarkable athlete after all.