The invention is an exercise device comprising (i) a frame, (ii) first and second foot supports operably associated with the frame for traveling along a closed loop path relative to a transverse axis defined by the frame, (iii) a means effective for sensing the speed of travel of the foot supports along the closed loop path, and (iv) a means for automatically adjusting the stride length and/or stride height of the closed loop path traveled by the foot supports based upon the sensed speed of travel of the foot supports.