At the very beginning of CFTS, in response to the question are sprinter born or made, Charlie replies that more often sprinters are unmade by improper training.
If Charlie had trained Tony Sharpe or Desai Williams or any of the others exactly how he trained Ben, they would not have achieved as high a performance level as they did. That also points to another aspect of prejudging how to train an athlete. If you read Speed Trap Charlie mentions how muscular and physically developed Tony was at 15, compared to scrawny little Ben. From first impressions you might think that Tony would excel from lots of high intensity work whereas Ben would not be able to tolerate it. As it turns out, it was exactly the opposite. Tony required more low intensity speed endurance work in order to recover, whereas Ben excelled with larger volumes of shorter, higher intensity runs.
If you look at most of the champs and record holders in the 100 over the last 20 or so years, not only are they all black, they’re mostly Jamaican: Ben Johnson, Linford Christie, Donovan Bailey, Asafa Powell, Usain Bolt. So they’re coming from an even smaller genetic pool. And yet, they all had different training programs with different workload distributions.
Again, what are the needs of the individual? You’re not going to know how it will play out ahead of time just by looking at them, whether it be based on race or initial physical development.