Ducks aren't made to be chased and can end up injured, their legs aren't made for running.
I didn't literally run around the yard lol.
I spent the afternoon tending my vegie garden and whenever he bit me, I turned around and mounted him.
Perhaps I should have worded that last comment better

I never let anybody chase my ducks (kids are the WORST for this because they just want to pet them). It stresses them out and as you said, they aren't built for it.