An abdominal twist exercise device includes a device frame, front and rear rotational axles, a main handle bar, a rotation converter, an adjustable gear, a disengaging lever, a weight, a weight bar, a support rail, a safety handle bar, rotation counters, and a user platform, such that when the main handle bar rotates to one side, the user platform rotates to an opposing side. A rotation converter can include a front chain sprocket, an intermediate rotational axle, an intermediate chain sprocket, a roller chain, an intermediate gear, a rear gear; or a front belt sprocket, a rear belt sprocket, and a twisted belt, connecting the sprockets. Optionally, the front and rear axles can be telescoping.

An abdominal twist exercise device includes a device frame, front and rear rotational axles, a main handle bar, a rotation converter, an adjustable gear, a disengaging lever, a weight, a weight bar, a support rail, a safety handle bar, rotation counters, and a user platform, such that when the main handle bar rotates to one side, the user platform rotates to an opposing side. A rotation converter can include a front chain sprocket, an intermediate rotational axle, an intermediate chain sprocket, a roller chain, an intermediate gear, a rear gear; or a front belt sprocket, a rear belt sprocket, and a twisted belt, connecting the sprockets. Optionally, the front and rear axles can be telescoping.

An apparatus for resistance training comprising a frame supporting: a rotational pivot for providing rotation in a vertical plane; a horizontal reaction arm adapted to be moved by a human user; and an actuation arm rotatably mounted on the rotational pivot and rotationally mounted on the horizontal reaction arm; such that a force on the horizontal reaction arm causes the reaction arm to move about the rotational pivot whilst remaining horizontal. The frame further comprises a resistance means arranged to apply a user-selected resistive force that must be overcome to induce movement of the horizontal reaction arm from a rest position. The actuation arm has a length that is adjustable by the human user. The rotational pivot is vertically moveable within the frame. The horizontal reaction arm is capable of being moved in both a clockwise or anti-clockwise sense about the rotational pivot.