According to Deno one of main reasons Usain Bolt was able to beat in an astounding fashion his doped peers is because he had a background in the 400m. The argument seems dubious at first glance but considering how well and how quickly Usain Bolt did at the 100m it does seem plausible. Consider also how Fred Kerley started dominating the 100m after specializing in the 4 all through college and even as a professional afterwards. Further consider how Michael Norman's PR in the 100 is 9.86 despite having ran it only a handful of times.
Given these statistics, is it fair to question whether it's fair to be able to run the 400m? If having a 400m enables one to beat dopers in the 100m, is running the 400m itself not a form of doping? Bear in mind that doping encompassing a variety of things and isnt restricted to just "steroids." Stimulants, etc anything that is considered an unfair advantage is doping. If running the 400m is an unfair advantage for 100m runners, should it be an event?