Another interesting German word is Sitzfleisch. It too is close in meaning to diligence, staying power. Fleisch is meat and Sitz, seat, is from the verb sitzen, to sit. One who has Sitzfleisch, then, has sitting meat. Think of a scholarly grind who sits for long hours poring over tome after tome of arcana.
And that reminds me of a story. Max Scheler and Nicolai Hartmann were German philosophers of high repute, though Scheler was more the genius and Hartmann more the grind. As the story goes, Scheler once disparaged Hartmann thusly, "My genius and your Sitzfleisch would make a great philosopher!"