Teddy Atlas mentioned that Marciano once trained throwing punches under water for half an hour. He said this unorthodox training contributed to his crazy stamina. There was also an Ali documentary where somebody mentioned that he shadow boxed underwater. Considering both of them had insane endurance and heart, Both known for crazy late round rallies, is this a severely overlooked aspect of their training that contributed to their stamina and overall success? If so why on earth have no trainers really looked into it? Or was it just some thing they did to build on their mythos and aura, wowing reporters?