America's greatest fitness success story

Fuente: Business Insider

Getty ImagesYou may be surprised to learn that the treadmill was invented as a prison torture device in 19th-century England. Or maybe you're not surprised, depending on your feelings about huffing and puffing as you trod along on an automatic belt to nowhere. Still, it's a little wild to realize that upward of 50 million Americans willingly use a device each year that was conceptualized to make criminals suffer.