Army Spc. Charles Parker looks on as Sven Zarling demonstrates the capabilities of a prototype prosthesis July 17 designed to give above-the-knee amputee servicemembers the mobility they need to remain on active duty if they choose. The prosthesis uses a microprocessor to control the knee's hydraulic functions and can anticipate the wearer's actions and make changes in real time. Mr. Zarling is from Otto Bock HealthCare, the company developing the new prosthesis. (DOD photo/Fred W. Baker III)