Abstract: The exercise machine in the present disclosure utilizes novel machine mechanics that accommodate and adjust to the spines shifting axis of rotation. Through the use of a multiple, articulating axes a back exercise machine or device that promotes pure and isolated spinal flexion and extension with no need for mechanical anatomical restraint to succeed has been created. Using these mechanics when users attempt to extend their trunk, the device adjusts to the natural shifting axis of rotation of the spine thereby dis-involving the contribution of the hip extensor muscles. In other works, the exercise back machine of the present disclosure is designed to accommodate the complex biomechanics of the spine and to facilitate targeted strengthening of the spinal erectors and deep intrinsic spinal muscles.