The treadmill was actually an instrument of punishment in prisons. The expression "to dance on a step mill" (as the prototype of the treadmill was called) meant "to serve a sentence in a jail".

In 1902, the step ladder was recognized as inhumane and its use was banned. Eleven years later, Henry Ford slightly modified the design of the "step mill" and turned it into a transporter. And some time later it became a familiar workout machine.