This raises the question then of whether 'ex-dopers' should be allowed back into a sport.
In the context of a professional athlete, I would think that androgens or other anabolic drugs leads very much to a long- to permanent advantage, doesn't it? You won't lose the extra gained muscle mass, because there is a relatively chronic training stimulus, and as pointed out it leads to a large increase in sustainable training load, which should also increase performance down the line, possibly influencing the 'central governor', if you believe the theory.
EPO receptors aren't only expressed in cells of the erythroid lineage. It is found in the brain, heart, skeletal muscle, kidney and endothelial cells (blood vessels). (1)
It not only increases Hb, but also stimulates mitochondrial biogenesis and angiogenesis(2), I would think that these new vessels and mitochondria should provide at least a long term improvement in training adaptations, shouldn't it?
Not to mention the genetic doping agents such as AICAR.
Furthermore if an athlete uses drugs at a young age and stands first in line when contracts are handed out, that's it, he's made it. I'm especially talking about sports like rugby where the juiced guy gets the contract at 18 and the second stringers are left behind, they missed their shot, so to speak.
Testing at that age really is near non-existent.
I'm currently moving towards the viewpoint that an athlete has to prove that he is clean. Move away from the 'innocent until proven guilty' viewpoint. Release blood data, power data and test results and prove that you are clean, rather than us proving guilt.
(1)
http://ndt.oxfordjournals.org/content/20/6/1025.full
(2)
http://circres.ahajournals.org/content/106/11/1722.full