I invite you in looking at the results of the last two years, from when the EPO tests frightened some athletes. There is some Country, before good, that now is really worse. Look at the seasonal lists of Morocco, Spain, Russia, for example. This doesn't mean that ALL the athletes of those countries were under drug, but that in those countries there was a CULTURE of some pharmacological support from the extern. But, looking at Ethiopians (and also Kenyans, not in Cross Ch., but on track, or Ugandians, or Eritreans), we can see that there is a general improvement in their performances. Do you think that is possible to last at top level with so much continuity like Gebrselassie or Bekele or El Guerrouj or Shaheen last year using drug ? See seasons of Boulami and Shaheen, see when Bekele is able running at his top, see when Gebre is competitive, see when Tergat beated his world records in 10000m, HM and Marathon, see the careers of Tulu, Ndereba, Chepchumba, and tell me if is possible to have so much continuity using drugs. The real problem is that human limits are very better than the current WR, because old talented athletes from Ethiopia and Kenya were not so well trained like now Bekele and other Ethiopians, but with a correct methodology (and without drug : this is good for improving only for athletes not very much talented and not well trained) I think that is possible, in 3 years, running 1:40.5 - 3:24 - 12:35 - 26:10 - 58:00 and 2:03.