agree with this guy...i grew up just south at the tail end of lake counties glory days. my dad would try to pick hanks brain on how he accomplished this and that. and he said back in the days it was easy, kids wanted to be fast so they trained hard. he said once they stopped wanting the glory no one trained and then they sucked and then no one came out for cross anymore. then hanks retired.
even renato mr i dont believe PEDs work on the top athletes...he says that when bekele's mind is right and not injured no one can stop him...duh.
like this guy said when you have 5-7 guys that can run sub 17 min 5k at 10,00ft, you can and will crush the schools in colorado. especially when the schools come up for the lake county invitational. my senior year we only had two guys sub 17, i was hi 17's low 18s at best and a mid 18...we one the race with a number of 5A schools in it. they were not ready for the altitude and cold. no way we would have been them at say liberty bell but we got them at altitude.
the main thing though is the "culture" there has to be a desire to make a name for yourself, either from the "team" you are part of or individually. in kenya and ethiopia the "team" is two fold, the training group your in, and the pride of nation. and the individual pride still has power. imagine how many people would have crushed if the Pre era had social media.....they would have been trying to one up each other to incredible times.
about altitude....there is more to it than just training. i think you need to put in a few years minimum of normal living and working hard to make lasting effects. i was born in colorado springs but raised at 8,000 my whole life. i never really improved at all at sea level but i would perform better % wise against people when the event was at higher levels than they were used to.