Like others said, some have motor issues.
I had to see neurologist to rule out a bunch of things around the time I was first assessed for autism. I had some balance and coordination issues or something.
But I find that I like some physical labor, especially if it is repetitive and a structured task. I did not mind harvesting potatoes, hoeing at weeds, planting seeds, mulching, etc. I liked the mostly straightforward tasks on the university farm whether it was 95 F or 50 F. It was sensory hell sometimes with the sweat, bugs, dirt, etc but the tasks cleared my mind a lot. No thoughts, just plants and dirt
I have the same feeling when I am clearing up the yard, cleaning the pool, raking leaves etc. It can bother me a lot sensory wise sometimes but I like having a clear task and working on it as much as I can before I tire out. But I have an aspergers dad and aspergers uncle that both went into the military so maybe they passed down that mindset of working on physical tasks or something.