Abstract: An exercise treadmill comprising a frame including rotatable drive and idler rolls, an endless mat extending around the drive and idler rolls and along the frame to support a person thereon, and a motor connected to the drive roll to rotate that roll and to drive the mat. First and second railings are connected to the frame and longitudinally extend above and along first and second lateral sides thereof respectively to help balance a person on the mat. The exercise treadmill is supported on a surface by an assembly including a tubular housing connected to the frame, a support arm slidably supported in the tubular housing, and a spring secured within the tubular housing and urging the support arm downward into engagement with that support surface.