i think if we could truly eliminate the dopers in the sport that you would see quite a bit of caucasians (americans, british, etc) performing in the top 5 on a continuous basis in distance running. the sprints are a total joke, especially for americans.
but the distance runners in america are by far the least doped runners out there. everybody hates the speculation but these guys like ramzi who show up for 1-2 meets and blow everybody away are not super genetic freaks. they are doped to the gills runners who spend all of their time and training planning for when the training and drugs will have the most optimum effect, namely they time this around olympics and wc. just a shame, really, for guys like willis. should probably have the gold.