They're not hired to swing a hammer hard, they're hired to swing it at the right thing, and if they can't swing it hard enough they pick a different tool.

Harder than someone else. A bodybuilder and a normal person ham swing a hammer just as efficiently as each other.

Dexterity is more important - after all you may have the stamina to bang in 1000 nails in an hour. I have a nail gun. What’s important is we can control where the nails go.