I try to warn my students to prepare for midterms and finals as an athletic event. If you're going to be clutching a pencil or pen for 2-3 hours at a time, writing furiously, then your hand needs some preparation.
Clutching seems to be my operative mode for writing when I grade. And since I sit still and grade for long periods (more than three hours at a time, for sure), I can feel it in my hand and in a sort of general antsiness/stiffness.
My thumb joint and second finger on my writing hand are a little sore. Unfortunately, I can't just change hands, since my other hand's primary life skill is holding down the paper while I write.
But the grading crunch should be temporarily over this afternoon, so I'll give my hand a nice soak in the bathtub with the rest of me!
One of my college friends had the most impressive callous on the second finger of his writing hand, just where he held the pen/pencil. I get sort of flattened skin there, but don't seem to develop a callous much.
Have you ever noticed if you look at your hands that some of your fingers seem to sort of twist in a weird way? Just me? (Nope, I'm pretty sure it's not arthritis, just my one finger sort of twisted outwards on each hand.)
Enough break, back to grading jail!