The Hitch said:
No not vice versa. You have proven that someone who is good young can become worse as their career progresses.
You have NOT proven that the reverse is true. The fact that losing form midcareer is natural does not mean that gaining it midcareer is natural.
Not all rules work in reverse e.g.. if someone does alpe d huez in 35.minutes that means they are doping. But if they do it in 45 minutes that doesn't mean they are clean.
TBH I don't think I've proven either, just posited an opinion. What I don't believe is that you can chart an athlete's career progression and arrive at a constant that can be held up as a 'clean' progression, and that deviation from it is indicative of nefarious practice.
Undoubtedly spikes in performance are massively suspicious and rightly worthy of investigation, but it not conclusive in isolation.
I think is an element of luddism at times when the desire is to take the argument to the simplest form. Rider A is clean, he rode climb X in 45 minutes. Rider B rode climb X at 43 minutes, ergo he is dirty.
In neutral, controlled conditions that would be an acceptable test. In a bike race it isn't: there are huge varaiables, from the epoc it was road in, the bike used, the gearing, the road temperature, the humidity, the air density, the surface quality, the tyre pressure, precipitation, wind speed, wind direction, what the rider had for breakfast.
But yes, there are abnormal results, unacceptable figures. But isn't 6kw/g the new 50%? Where are the abnormal performances we can hang our hat on and say for certain that's dirty? People aren't riding climb X at 35 minutes.
And as far as form goes, it can easily come and go, and so reasons why too. Definitely less markedly in an endurance sport not a skill one, but there's a big thing called the mind, and if that goes wrong the numbers are immaterial. Nibali's win in the Giro was as much of a test of mental fortitude as physical strength. Wiggins failure ditto. On paper one rider should be superior to another, but no matter how strong the legs are if the head isn't with them then it won't count for much