Gymnasticon

"[3] The Gymnasticon depended on a set of flywheels that connected the wooden treadles for the feet to cranks for the hands, which could drive each other or operate independently.

"Each treadle has two, and the centered Screws which pass through them embrace the cross, or lower extremities of the treadle-lifters, GG, so as to admit of easy motion.

In his patent, Lowndes described the machine as intended simply "to give and apply motion and exercise, voluntary or involuntary, to the limbs, joints, and muscles of the human body.

[4] A magazine article at the time noted, however, that Lowndes had claimed success in using the machine to treat "gout, palsy, rheumatism, debility, contraction, etc.

"[5] It was specifically designed for the sick, with an external crank that could be used to force involuntary motion in the joints of a person too disabled to work the machine alone.

Engraving of the Gymnasticon in action, 1798
Mechanism of the machine, from Lowndes's patent application. Figure 2 shows a treadle and the crankrod it drives, figure 3 the flange that supports the upper cranks (labeled K ).