This is a somewhat simplistic take. Yes, people worked with their hands, but there were also other factors in the mix:
* frequent starvation or food insecurity among anyone but the high class, not good for overall physique,
* high parasite load sucking you dry from within - read up something on how massive infestation with hookworm can sap big, adult men of power,
* infections like tuberculosis.
I would be surprised if a 16th century peasant had more muscle than a 21th century student who does at least some sports. They would be a lot more used to physical work, yes, but that is not the same as "our muscles have atrophied".
If anything, we might have weaker sinews, but not muscle per se, and our bones are almost certainly stronger, as we lack neither calcium nor important vitamins.
* frequent starvation or food insecurity among anyone but the high class, not good for overall physique,
* high parasite load sucking you dry from within - read up something on how massive infestation with hookworm can sap big, adult men of power,
* infections like tuberculosis.
I would be surprised if a 16th century peasant had more muscle than a 21th century student who does at least some sports. They would be a lot more used to physical work, yes, but that is not the same as "our muscles have atrophied".
If anything, we might have weaker sinews, but not muscle per se, and our bones are almost certainly stronger, as we lack neither calcium nor important vitamins.