U.S. Air Force Senior Airman Marcello Yamaguchi, 446th Aeromedical Evacuation Squadron, Joint Base Lewis-McChord, Wash., performs a push-up using a helmet at Fort Hunter Liggett, Calif., May 16, 2011, in support of Global Medic 2011 and Warrior 91 11-01. Global Medic is a joint field training exercise for theater aeromedical evacuation system and ground medical components designed to replicate all aspects of combat medical service support. Warrior Exercise gives participating units an opportunity to rehearse military maneuvers and tactics such as security, convoy operations and quick reaction drills during simulated enemy attacks. (U.S. Air Force photo by Senior Airman Raymond A. Estes/Released)