"There must be some kind of movement I can do standing up, with the dignity of a human being,"
Take a sledgehammer and wrap an old sweater around it. This is your "shovelglove." Every week day morning, set a timer for 14 minutes. Use the shovelglove to perform shoveling, butter churning, and wood chopping motions until the timer goes off. Stop. Rest on weekends and holidays.
I do 50 shoveling motions, 50 right then 50 left; 15 to 20 butter churns, right then left; 20 woods chops in both directions; and then 5-8 curl like movements for which I haven't thought of a good name yet. Then I repeat the cycle until the timer goes off.