Matthew Burks, Wounded Warrior athlete, works on his swimming technique Aug. 4, 2014 at the U.S. Air Force Academy, Colo. The Wounded Warrior athletes are conducting their final group practices prior to the upcoming Invictus Games in London Sept. 10-14 and the Warrior Games Sept. 28 through Oct. 4 2014. (U.S. Air Force photo\ Staff Sgt.Tim Chacon)