The present invention provides a means of exercising wherein the gross body movements of the body during exercise are Kinesiologically Correct, meaning they are governed by the specific forces, specific physiology and specific mechanics according to the natural movements of the body when effected by gravity. The body is supported during the body weight resistive exercise in such a way that the body is maintained in a position the body naturally tends toward when unassisted during a body weight resistive exercise accomplished by the way in which the user interfaces with the machine. In performing assistive exercises, wherein the weight of the user's body is made lighter, the user's body is being pushed upon by the guide arm of the machine while force is being applied to the guide arm through a bi-direction force transferring means. In performing resistive exercises, wherein the weight of the user's body is made heavier, the user is pulling upon or harnessed to the guide arm of the machine while force is being applied to the guide arm through a bi-directional force transferring means. The force engine comprises a force production mechanism and a force transferring means in which the force is created by the force production mechanism and transferred to the guide arm of the machine by the force transferring means.