A dog is exercised on a conventional a treadmill by locating the dog on the treadmill by providing a support base mounted on the ground underneath t he base of the treadmill and held in place by the base of the treadmill and an upstanding support member extending from the support base at the front end o f the treadmill, and confining the dog within an enclosure supported in cantilever manner by the support member and extending rearwardly therefrom so as to be support ed by the support member over the walking surface such that the dog is position ed within the enclosure on the walking surface. The enclosure has a front wall and side walls extending from a bottom edge close the walking surface and within the side edges thereof to a height above the dog to restrict its vision.