The predecessor of fitness equipment, the bizarre invention history you don't know
Most people in the gym like to run on the treadmill to keep fit, but what you can't imagine is that the people who invented the treadmill didn't use it as a fitness equipment at all, but as a torture tool for prisoners. Hundreds of years ago, humans built farm tools similar to treadmills, such as European mills, which use a large, rotating wooden disc in situ to connect gears, and people can drive the machine by stepping on the wooden disc.