I tried the moving bed, but I kept running out of quarters.
-Groucho Marx
But seriously - I just last week bought off Ebay an electric muscle stimulator to test. Pretty simple. You place an electrode pad at each end of a given muscle (biceps, for example). An electric current is pulsed through the muscle making it contract with each pulse. Safe, runs off nine volt battery. (Note: Assumption alert!) I had intended it for my lower legs but it may well have wider uses. Will report in. Ignore any reports of spontaneous human combustion from Tennessee.
Squeak! Squeak!