What I wonder about are the other untalked-about physiological changes necessary for “super strength” to be a reality. For example: skin.
An ordinary shmuck like you or me finds it pretty easy to get cut. Hell, I tore open the knuckle on my thumb yesterday when it dragged against my desk wrong, and it didn’t take very much pressure to do it.
Now, take lifting, say, 80 tons, which the Hulk can do quite easily. Unless you’re positioned perfectly directly underneath that sucker, there’s gonna be some “pull” on your skin somewhere. And your skin has to resist tearing against 80 tons of apartment building (or whatever) tugging it off your heroid frame. Basically, your skin would have to be diamond-hard and virtually compression-proof to accommodate your super-strength, which would make a superhero pretty darn conspicuous in everyday life. I mean, if I poked Clark Kent and his skin didn’t indent in the slightest, I’d get suspicious, ya know?
For that matter, to remain mobile, the fluid in the hero’s joints would have to remain uncompressed under all that weight, as well. And neglecting the size of the hero’s feet, think about how much pressure that weight is putting on his relatively small spinal column.
All bets are off if you’re a god like Thor or you have powers that only appear when the magic’s on like Golden Boy in Wild Cards. They can get by, I suppose. And actually, it’s thinking about stuff like this that allows me to forgive some stuff in hero movies and comics, like Spider-Man enduring a pumpkin grenade blast at close range; I just figure his skin’s harder than a normal person’s, to allow his super-strength to function.