Abstract: A quadrilateral exercise and training device includes a plurality of longitudinally extending channel members mounted on cross frame members so as to define elongated slots in which foot-supporting members and hand-engaging members can reciprocate. A control system interconnecting the foot-supporting members and hand-engaging members includes a main flat synchronizing belt interconnecting the foot-supporting members and hand-engaging members to establish desired coordination between the respective members, a safety belt interconnecting the foot-supporting members and a drive belt associated with each foot-supporting member which operatively engage a pair of drive shafts having a braking system and an optical transducer for converting rotation of one of the drive shafts to a digitized informational readout for use by an operator.

Abstract: An exercise device for simulating cross-country skiing includes a plurality of longitudinally extending channel members mounted on cross frame members so as to define elongated slots in which trolleys for foot supporting members and hand engaging members can reciprocate. A control system interconnecting the foot supporting members and hand engaging members includes a main drive pulley interconnecting the foot supporting members for coordinated reciprocal movement and a secondary belt interconnecting the foot supporting members and hand engaging members so that each hand engaging member will reciprocate in an opposite direction to its associated foot supporting member and at a speed of twice that of the foot supporting member. A resistance structure is provided for resisting movement of the trolleys to provide a selected level of exercise.

Abstract: An apparatus for closely simulating cross country skiing includes a platform on which right and left foot engaging supports are disposed for reciprocatory sliding movement with right and left hand engaging members being operatively connected to the foot engaging supports to reciprocate in a pattern simulating cross country skiing. A control system is employed for controlling the relative movement of the foot engaging supports and hand engaging members so that a slight amount of play exists between the foot engaging supports permitting a smooth gliding motion. Means are also provided in the control system for allowing the hand engaging members to move twice as fast as the foot engaging supports so that the relative movement between the hand engaging members and foot engaging supports more closely resembles actual cross country skiing.