There is no rule saying that there will be Stack Exchange site for your question.
Only answer I can give is - nowhere on SE, because it's bad question on all sites it might touch.
Not here
It does not belong to worldbuilding because you are not building any world, just putting some numbers on things that actually exists, and these numbers won't even exist in your world.
Not on biology
It does not touch the biological aspect of strength. At all.
Not on RPG with D&D tag
Sorry, but D&D never aimed at replicating reality. It's just a game system, a way to create stories, not a reality simulator. And you pretty much will get the same answer under other systems.
Rethink your idea, maybe?
For a roleplaying game, do you even need to have physics behind that stat?! Would your players bother, or get bored? I bet it's the latter. That's why most of the RPG systems are more about play and less about reality. Too much reality gets tiresome, boring, and slow.