I’m guessing that since it increases red blood cells, you therefore carry more oxygen in the blood. More oxygen to the muscles = better performance, more stamina. Perhaps, since one can perform better, one can push harder during training, so it helps to build muscle in an indirect way.
Your RBC count would be sky high.
If he’s taking testosterone, the levels might actually be lower since it suppresses the body’s levels.
I think in summary, this is the bottom line. Armstrong, realizing that “virtually everyone cycling” is doping, figured that he’s not going to get beat by someone who is doping. So he sets up a sophisticated system to beat them at their own game.
If we’re talking about affecting muscle type, fast twitch vs slow twitch, (these guys are all slow twitchers I’m sure), then what he’s doing might in fact increase his stamina.
the other thing, is the benefits would come during training periods, and not be detected on race day.
What is the downside to taking EPO? Does it have long-term health ramifications?