An exercise apparatus for aerobic conditioning of a person having a flexible rod over which the person must jump in accordance with a rhythmic cadence. A variable speed control device controls the speed of movement of the rod. A light beam may be utilized to replace the flexible rod. The user jumps onto...http://www.google.se/patents/US4813665?utm_source=gb-gplus-sharePatent US4813665 - Aerobic skipping exercise device
