Hearns also outboxed Virgil Hill at 175, who was similar in physical size to him and also an excellent boxer. As an amateur, Hearns was known more as a stylist than a slugger. In fact, his main problem as pro was that he could be drawn into wars. When he chose to box and work behind his jab, physical advantages or not, he was extremely difficult to deal with.
His stamina also seemed to be a bit of a problem. All of a sudden he got tired late in the Leonard fight and was out on his feet pretty much after 1 combo. His chin and stamina was problems for him.
Hearns weighed in at 145 with a same day weigh in plus the fight was a fifteen round fight and fought at a frantic pace. Coming in that light wasn't probably the wisest choice. Like I said before, everyone that stopped Hearns could crack. Given the way he liked to get into firefights with his opponents, his chin held up pretty well and he would have suffered more stoppages if his chin was bad as some people make it out to be.
Paul Williams was roughly the same thing. Guillermo Jones was even bigger. I can't find any pictures of him when he was young but the poor boy must have looked like he fought out of Auschwitz concentration camp. Alexis Arguello probably counts "the explosive thin man" known for his bizarre height for the weight class and awesome power. It's like "Of course, Arguello hits hard at featherweight. He's the size of a middleweight!" To a slightly lesser extent, the same is true of Sandy Saddler with his 103 KOs, or Bob Foster. "Gee, that guy who's 3-4 inches taller than all of his opponents has a lot of knockouts. It's a total mystery."
I know that he got knocked out 4 times, but I don't think he had a horrible chin. All 3 guys (Leonard, Hagler, Barkley) hit like light-heavyweights. Leonard and Barkley even boxed in those divisions. It wasn't like he could be bombed out by your typical welter or a feather fisted middleweight. His chin and power were just alright for a man of his proportions. What made him phenomenal was his ability to function many weight classes below what was normal for a man of his size. If he had stamina problems, it was probably just because he had so little fat on his body.
I just don't think being tall automatically means you should hit hard. The only advantage I see a tall guy of the same weight hitting hard is more leverage. But Hearns could crack even without fully extending the arms. Though when he did get the full leverage it was scary. As we saw with his KO of Duran.
Some guys are just low stamina fighters. Its not like you can just become super fast or a super high workrate fighter just by wishing it. Miguel Cotto was a low stamina fighter despite all indications that he trained hard and trained seriously. It just happens. There were some glaring weaknesses with Hearns. First his chin, second his stamina.
I think genetically, he was just meant to be a light heavyweight. That means light heavyweight bones and light heavyweight muscles. Biologically, that's just what he was and he wound up at that weight automatically later in life. Where guys like that have control of their destiny is in the environmental factors like diet. Even though he doesn't have the fat levels most other guys his size possess, he has the same kind of muscles which are necessary to support such a frame. Thus, he pretty much just hit like other guys his size would, even though he weighed much less. Now, I'm not saying that all light heavyweights can crack, and being that much lighter probably limited his muscle mass a little too. But as a general rule they all crack harder than welterweights.
Its normal for tall skinny guys after age 25 to put on weight. Which is what Hearns did. But at 147 and 154 Hearns was not a muscular guy. He wasn't carrying that much muscle mass for his frame.
Of course, he didn't have huge bulging muscles at 147 or 154. He had lean muscle distributed evenly over his body. His frame was 6'1" with 78" inch arms. That is a lot of bone to spread muscle over. If you put all his muscle on a typical 5'8" welterweight with 70 inch arms you would see some bulging muscles. That much muscle on a typical welterweight would look roided out like the Incredible Hulk.
Now a guy like Victor Postol I can't figure out. The man is 5'11", 73.5" fighting at 140 lbs but he's as weak as a kitten. He must have some **** poor technique not even using his leverage properly, like Nikolae Valuev throwing nothing but arm punches, or else he's not cutting and maintaining his weight properly. Ie there are good ways and bad ways to put on or take off weight. For instance, Juan Manuel Marquez lifting rocks, cupping therapy, and drinking **** was a bad way to train to move up two weight classes and fight Floyd Mayweather. Of course, some people have bad genetics and are feeble at any weight. All the muscle in the world isn't helping Tim Bradley. Of course, he could probably get more bang for his buck if he stopped lifting so many weights and slimmed down to fight lightweights. He's only 5'6" after all.