IIRC, the Jamaicans basically defunded their drug enforcement, hired known pro-doping coaches, basically have a "team chemist". The Jamaican sprinting explosion followed.
I want to make clear that Jamaica is not an outlier or "bad guy". Really they are small fry in the industrial olympic sports machine. What they really are is a window into what the big time countries do.
It of course helps that sprinting is a national obsession in Jamaica, so the best athletes do sprinting. But that's been true for a long time.
Personally, I do not think humans can run faster than 9.90 in the 100m without "aid". or under 20.00 in the 200, or under 44 in the 400m.
I do not think a human can run faster than 13:00 in the 5000m, or 27:00 in the 10,000m, or somewhere around 2:08 in the marathon.
But those are personal opinions.
