We are well aware that a treadmill is an exercise machine for running or walking in one place. However, it might be surprising to learn that, there is an invisible link between the modern gym equipment and the cruel punishment imposed on the prisoners in Victorian prisons.
Before the development of power operated machines, treadmills were often used by a type of mills that was operated by a person or animal treading steps of a treadmill to grind grains. However, in 1818, a British engineer named Sir William Cubitt introduced a new type of treadmill, known as tread-wheel, as a means of usefully occupying convicts in the prisons at Bury St Edmunds and Briton. Actually, it was a type of fruitless labour intended for punishment. Oscar Wilde was made to toil away on the treadmill during his imprisonment in Reading Jail in 1895.
The prison treadmill was a long wooden cylinder with metal framing, about six feet in diameter. On the outer side of the cylinder were wooden steps about 7.5 inches (19 cm) apart. It was, in fact, an "everlasting staircase". As soon as a prisoner put his weight on the step it depressed the wheel, and he was forced to step onto the step above.
There would be 18 to 25 positions on the wheel, each separated by a wooden partition, so each prisoner had no contact with the adjacent prisoner and saw only the wall in front.
The use of prison treadmill, otherwise known as a penal treadmill, was abolished in Britain in 1902 by the Prison Act (1898) but the term was resurrected, when it was applied to an item of gym equipment likewise comprised of a (seemingly endless) foot-powered belt.