> The short answer is that a typical modern person (gamer or no) is much less fit than anybody from the age of melee weapons, let alone knights.

But I don't have smallpox. Or cholera. Or an iodine deficiency, because I live so far from the ocean.

That is another discussion since we are talking about fitness, specifically upper body strength and endurance, not rates of illness.

So if you had most of those things you'd be dead and therefor not factor into this discussion. The ones who didn't die were much stronger than the average person today. They had to be.