Treadmill, << TREHD mihl, >> is a wheeled mechanism rotated by people or animals walking on or inside the wheel. A treadmill with an axle is called a wheel and axle (see Wheel and axle ). The movement of the wheel turns the axle and any mechanical device attached to it.
The ancient Romans used treadmills for such tasks as grinding grain, lifting water out of mines, and powering cranes that hoisted construction materials. People and such animals as cows and horses provided the power for these devices (see Threshing machine ). Treadmills were used for heavy work until the 1700’s and 1800’s, when they were replaced by steam and hydraulic engines. Today, many people exercise indoors by walking or jogging on powered devices called treadmills. Tiny treadwheels provide exercise for hamsters and other small pets in cages.
See also Stress test .
