Definition of Treadmill

Treadmill: A machine with a moving strip on which one walks without moving forward. A treadmill was originally a wide wheel turned by the weight of people climbing on steps around its edge, used in the past to provide power for machines or as a punishment in prisons. The treadmill today serves as a device to maintain physical fitness. It is also an essential component of the exercise treadmill test, a stress test for heart disease.

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=19799
Last Editorial Review: 3/19/2012