Abstract: A rotary torso comprises: a frame with a base, several supporting columns vertically installed on the base, a U shape railing installed a little bit above the supporting columns, and a U shape handle installed at the top of the supporting columns; a hollow box shape rotating arm, with one rotatable end pivot installed by a shaft bearing at the central bottom of a fixed shaft; a rotating plate, with a rotatable central hub, supported at the rotating shaft at the free end of the rotating arm; and a driving structure installed inside the hollow part of the rotating arm.

Abstract: A body twist exerciser, including a base, a guardrail mounted on the base, a rotatable hollow box-type rotating arm having one end pivoted to a fixed shaft in the center of the base, and a rotary disc rotatably supported by the center part thereof on the free end shaft of the rotating arm. A transmission mechanism is located in the hollow interior of the rotating arm. The transmission mechanism includes a drive sprocket fixed to the free end shaft of the rotating arm and located below the rotary disc. A driven sprocket is spaced-apart from and mounted side by side with this drive sprocket on a revolving shaft approximating the base end inside the rotating arm. A loop-like transmission chain is wound between the drive and driven sprockets and a transmission gear is mounted on the revolving shaft below the driven sprocket. An intermediate gear is rotatably disposed on an intermediate shaft between the fixed shaft and the revolving shaft to be engaged with the transmission gear.