The problem of every poster in Letsrun is that NEVER they use the word TRAINING. When there is some improvement, everybody think that the training was the same, and the progress is due to doping.
The reality is very different. Looking, for example, at Jemima (I don't want to say she didn't use EPO : I want to explain something different that changed her career), we need to know that already in 2006, when she had a poor management, and a very little training, was able to run 10 km in 31'15" winning the 10 km on road in Atlanta, and showed good natural ability to recover after hard training, running in two following days two competitions of 10 km, the first on 13th May in Jersey City (2nd in 32'13"), the second the next day (14th May) in Cleveland, when she won with 32'19". All this with very little training (about 50 miles per week) both as volume and intensity. In 2007 she ran in Frankfurt marathon with the training of a junior (less than 100 km per week, and not long run) in 2:29'41", and after this quitted running, married, gave birth to a baby, and came back in 2012 training in professional way under Claudio Berardelli, immediately arriving 2nd in Boston in a tactical marathon (2:31:52) and showing good qualities. In 2013 she won Rotterdam in 2:23'27". then was 2nd in Chicago in 2:20'48", and after that time practically didn't improve anymore.
This development of career doesn't produce any suspicion, because is the normal evolution for some athlete with good talent who finally starts training in proper way.
This said, if it's acclarated she used EPO, we can't give EPO the merit of an improvement of 9' after many years of poor training.
What I want to try to explain, but here almost nobody wants to understand, is that many improvements are natural with the change of training, because in Kenya there are a lot of talented athletes who train very little, without eating enough and in poor conditions, and of course their results are of medium level only. This trend can continue for several years, till when the athlete is lucky to find some other athlete of top level inviting him in his camp for pacing himself. At this point, if the athlete has talent (for example, this is the case of Dennis Kimetto), and finally can eat two times per day, can run twice and can recover, improvement of 10 minutes from his previous PB is absolutely normal, and a 2:16 in difficult training conditions can easy become 2:06, without any doping.
The problem is the posters of Letsrun don't know the real situation of African athletes (not the top, but the hundred having talent but poor preparation and no assistance), are not able to recognize a real talent, don't know anything about the training of top athletes, and use as parameter the activity of average athletes that don't have any common point with talented African.
Of sure, a Kenyan athlete running 2:06 in 1985-1990, when also European were able to run in 2:07 (Carlos Lopes and Steve Jones), to win Olympics (Bordin 1988) and Boston (Bordin 1990), to win New York (Pizzolato 1984 and 1985, Poli 1986), didn't produce in the general mentality any suspicion of doping, because was at that time normal to see white people running under 2:10.