prime pacquiao is definitely a name to put on the list to debate
especially when going up weight classes and continuing to carry that conditioning, speed, and power...
I'd say Calzaghe deserves an honourable mention... but then he didn't always put a lot on his shots later on so might not have expended a lot of energy but early on in his career with better hands when he wasn't always slapping he could still fight at a very fast pace for 12 rounds. Pretty good stamina for a 168lbs guy.
Comment