I know this has been debated to death on dozens of threads but Renato sometimes (mainly when it is convenient for his theories) speaks of HCt and Hb levels as if an athletes blood volume is fixed.
The Hct and Hb tests use a fixed and very small amount of drawn blood to determine hematoctrit percentage and hemoglobin count from the 10 ml or so of blood that is drawn. What a normal blood test can't do is determine the total blood volume of an athlete. That is why Olympic cross-country skiers in the early 2000s used plasma-increasing drugs and transfusions to rebalance Hematocrit percentage back below 50%.
No one is arguing that runners could rely on EPO to obtain elite level performances without serious training. In fact, it stands to reason that EPO doping without endurance training would be dangerous and counterproductive as blood would get thick and hard to pump. However, as Renato mentions, one of the primary effects of endurance training is an increase in blood plasma volume. Couple good training with smart EPO micro-dosing and you get runners with slight boosts in Hct/ Hb counts while still getting significant but not incriminating performance boosts.
The argument that elite runners would not benefit from EPO use beause they have already maximized their usable amount of red blood cells is both biologically unlikely and counter to available results. The fastest climb of Alp de Huex still belongs to Pantini, Mr. 60% himself. In track, the 1500, 3000, 5000, 10000 meter world records were all achieved well prior to the ABP and most done before any sort of EPO test was available at all.
At a certain point, Ochahm's Razor comes into play and the simplest explanation becomes the only plausible explanation. Consider the following summation.
In 1992 the 5k WR was 12:58 and the 10K WR was 27:08. Both were achieved on modern surfaces by highly professional, well-paid and well trained athletes with high-altitude backgrounds.
Then a drug called EPO becomes available. At the same time, elite performances in two well-established sports, track and cycling, drastically improve. In the space of six years a flood of runners break the old 5k and 10k WRs and by 1998, just six years later the 5k WR is 19 seconds faster at 12:39 and the 10K WR is 48 seconds faster at 26:20! If we were to take the 1992 5k and 10k records in reverse those same amounts we would have to go nearly 25 years back to Ron Clarke circa 1966 during the introduction of synthetic tracks.
Then, a test for the EPO is introduced circa 2001. The test is not perfect and is best at detecting blatant recent use rather than low-level micro dosing. Still, the cascade of falling WRs slows to a trickle with only minor improvements in the 5k and 10k. In 2009 an athletic blood profile testing program is implemented that, when enforced, is designed to detect doping of various sorts by comparing changes in athlete's biological markers in addition to direct tests for banned drugs.
After the ABP is introduced in 2009, no one, not even the WR holder himself who was only in his late 20s in 2009, has come within 20 secs of the 10k world record or within 8 seconds of the 5K WR.
What should we conclude from this? The simplest answer is that the drug, EPO, improves endurance performance, including the performances of the best, most well trained athletes in the world. Is it possible that something else or a combination of factors could explain the phenomena that has in fact happened in track and cycling from 1990 through today?
Yes, it is possible.
But EPO does exist, it does boost red blood cell counts, the performance improvements did occur, the improved EPO and ABP tests were introduced, and sub 12:45 5ks and sub 26:40 10ks have disappeared from the realm of possibility after the introduction of the ABP.
So I have a question for the Renatos of the world.
What is the elite training that HG and Daniel Komen and Paula Radcliffe and Keninese Bekele were doing between 1995 and 2008 that Henry Rono and Said Auoita and Mirtus Yifter were not doing in the 1980s and that Caleb Ndiku and Mo Farah and Keninese Bekele and Jemima Sumgong are not doing now?
If someone can credibly answer that question then we can stop arguing about blood values and the like.