I puzzled over this until I realised that the picture you have of me (and possibly of Stumpi, too) is of a body sitting on the saddle pedalling with one leg while the other pedal goes around freely on its own.
Not so. Should have been clearer: one REAL leg. Plus one plastic/metal combination. With which I pedal. Not quite so efficiently as with the real one, of course, since the absence of a calf muscle slows things down, but I can still bring my body weight to bear and unlike many amps (above knee) I still have my thigh muscles in reasonably good working order.
I shall post pics of me on bike with which you can scare the horses.
Allen
