How distance runners manage to rack up a high number of reps at almost all-out speed reveals both the benefits of such sessions and the foundation on which they're built
Although not quite as fast as Rod Dixon, but approximately the same era, another runner with a wide range was Johnny Halberstadt, who at least for a while was living in Boulder. His mile PR is under 4 and he has raced ultras, including finishing second in the very competitive 55-mile Comrades (ultra) Marathon in South Africa. Hos PRs for several distances, including 100K, are at the end of the article in this link: https://www.modernathlete.co.za/2009/09/johnny-the-great-all-rounder/
Although not quite as fast as Rod Dixon, but approximately the same era, another runner with a wide range was Johnny Halberstadt, who at least for a while was living in Boulder. His mile PR is under 4 and he has raced ultras, including finishing second in the very competitive 55-mile Comrades (ultra) Marathon in South Africa. Hos PRs for several distances, including 100K, are at the end of the article in this link: https://www.modernathlete.co.za/2009/09/johnny-the-great-all-rounder/