Treadmill
A treadmill is commonly encountered today as a piece of indoor sporting equipment used to allow for the motions of running or walking while staying in one place. The word treadmill traditionally refers to a type of mill which was operated by a person or animal treading steps of a wheel to grind grain.
The principle is a belt system (an electric motor or flywheel connected to a circular run of material) where the top of the belt moves to the rear so as to allow a runner to run an equal, and necessarily opposite speed. Thus the speed of the run can easily be set or measured (the rate at which the belt moves is the rate at which the runner moves). The more expensive, heavy-duty versions are motor-driven. The simpler, lighter, cheaper versions are passive, moving only when the walker pushes the belt with their feet, and operates just to resist the motion.
Treadmills were historically used as a method of reforming offenders in prison, an innovation introduced by Sir William Cubit in 1817; these were also termed treadwheels. The first private health club in the U.S. was started by Professor Louis Attila in 1894, but cardio workout machines entered the clubs much later and were developed initially for the hospital. The first medical treadmill designed to diagnose heart and lung disease was invented by Dr. Robert Bruce and Wayne Quinton at the University of Washington in 1952. Dr. Kenneth Cooper's research on the benefits of aerobic exercise, published in 1968, provided a medical argument to support the commercial development of the home treadmill and exercise bike.
