An exercise board sized to the patient's abdominal area provides for maximum lateral range extension of the shoulder rotator and limb musculoskeletal system. A ferrous loaded exercise disk on top of a flat surface sheet is magnetically coupled to permanent magnets housed below in a laterally free space to establish a magnetically induced lateral frictional resistance against the patient's lateral force on the disk anywhere on the plane of the surface sheet. An incline exercise apparatus is formed by combining the board with an incline stand and a rope, pulley and pull ring, allowing a patient's good limb to assist in rehabilitating the acutely impaired limb, as from stroke, shoulder rotator damage, or surgery. Circuitous indicia paths, some with obstacles for the disk, provide a method for the determination the patient's range performance and energy expended.