This goes to the heart of athlete development, which is really what this thread is about, how best to judge the trainings needs of athletes.
When talking about progressing from junior to more senior levels of development, coaching continuity plays a big role. This is why Charlie’s experience and insight is so valuable. I don’t know of another coach that trained sprinters from scratch to world class level on a consistent basis and without recruiting or screening athletes. He simply coached whoever showed up. The fact that most of his athletes were black had more to do with where he was coaching. That’s who showed up. If he had started in a predominantly white section of town, would the ethnic makeup of sprinting elite in the 80s have been different, at least from the Canadian quarter?