I don't remember about endurance training or tactics taught at that time. I do remember Dempsey fought bare knuckles in barns against his brothers and friends as a kid. Boxers in that era rode the rails fighting in small towns all across America.

The accounts of his fight against Jess Willard are crazy. Like Liston v Ali, sports writers thought Willard would literally kill Dempsey. Instead Dempsey was the one who delivered an unimaginable beating that sent him into super stardom.

I really, really wish I could have seen Dempsey and Joe Louis.