While doing some research for my upcoming keynote lecture in June, one of the men I'm researching made a reference to how treadmills were originally used for punishment in prisons! I found this intriguing so dug into it, and sure enough--it's true. Who knew?! Here's an interesting summary of the history of treadmill machines and how they factored into crime and punishment and eventually into the modern fitness industry.
*Source: https://daily.jstor.org/treadmills-were-meant-to-be-atonement-machines
*Graphic: Wikipedia