Forget the elaborate physics break-downs, if any fighter or trainer had the answer to Tyson's concussive power, you can bet your ass they'd work 24/7 ta do it. But, no one's been able to. That's why -- in all of boxing -- there's only been a handful who light-people-up like Tyson.
Steroids?? :rofl He's not a very tall guy, which made his frame easier to fill out and gives the illusion of much fuller, rounder muscle bellies. On top of short limbs and small joints.
Also... Steroids are (A) far more common than people realize, and (B) far more overrated on ESB than even a lot of fighters which is saying something. It's an illegal slight edge yeah, but it's not a god damn WMD.
punching power is pretty much something your born with, as far as Hearns and Tyson and such go the guys that can really bang tend to have 2 kind of frames long and lean like Hearns and Arguello and such or stocky with huge legs like Tyson and Tua and such.