Tyler'sTwin said:
This is usually explained by them barely participating prior to the 90's. So the influx of lots of great EA's just happens to coincide with the introduction of EPO.
The Olympics:
1968
1500m Kip Keino (Ken) Gold
5000m Kip Keino (Ken) Silver, Taftali Temu (Ken) Bronze
10000m Taftali Temu (Kenya) Gold, Mamo Wolde (Eth), Silver
Marathon Mamo Wolde (Eth) Gold
3000m Steeplechase Amos Bowiott (Ken) Gold, Ben Kogo (Ken) Silver
1972
1500m Kip Keino (Ken) Silver
3000m Steeplechase Kip Keino (Ken) Gold, Ben Jipcho (Ken)
Marathon Mamo Wolde (Eth) Bronze
1976 - African boycott because of Kiwi rugby players
1980
5000m Miruts Yifter (Eth) Gold, Sul Nabambui (Tan) Silver
10000m Miruts Yofter (Eth) Gold, Mohammed Kedir (Eth) Bronze
3000m Steeplechase Filbert Bayi (Tan) Silver, Eshetu Taru (Eth) Bronze
1984
10000m Mike Musyoki (Ken) Bronze
3000m Steeplechase Julius Korir (Ken) Gold
1988
800m Paul Ereng (Ken) Gold
1500m Peter Rono (Ken) Gold
5000m John Ngugi (Ken) Gold
10000m Kip Kieli (Ken) Bronze
3000m Steeplechase Julius Kariuki (Ken) Gold, Peter Koech (Ken)
So you're absolutely right. The Eastern Africans achieved nothing before the 90s and it's all down to EPO. (To help your counting , 'barely participating' yielded 12 Gold medals, 7 Silver and 7 Bronze).