This is your "proof"? That Amy & Dave are fakes because some previous guy(s), one of them named Dave, supposedly cheated? It's amazing that sort of logic is considered useful, but the Internet has always been stupid.
They all cheated and we have proof of that.
It looks like that Amy and Dave have no proof that Amy ran 520 miles, just that she was on a treadmill a lot for a week. Unfortunately we have no idea how the distance was covered.
There is actually a logic which says that Amy is probably not good enough to run 520 miles in a week.
But hey she can always sign up for a real 6 day race and run something like 400+ miles. We would all eat our words.
Past experience shows that this probably is very unlikely to happen.
The great Robert Young also said it was a big misunderstanding and he would run a 6 day race this Spring. It did not happen because it would have been a disaster for Robert Young. No way he would have covered 70+ mile days.
Again, if Amy runs a 400+ mile 6 day race she will be recovered until then it's just she said (520 miles) against he said, that would be us ( she is a fraud).