Two University of Oregon professors, Barry Bates and Janet Dufek, (1) ................. the benefits of backward walking and running on people since (2) ........... . They found that backward walking creates reduced force on the knees, and may be (3) ............. for any one experiencing pain going up and down stairs. Walking backwards (4) .............. more energy in a shorter period of time. It is good for (5) ...........recovering from illness because of reduced hip range of motion.