Capt. Sarah Freidel, 34th Bomb Squadron flight surgeon, checks the patella tendon reflex of Staff Sgt. Jacob Appleby, 28th Medical Operations Squadron ambulance services technician, during a physical exam in the flight medicine clinic on Ellsworth Air Force Base, S.D., May 2, 2012. Flight medicine is responsible for determining if Airmen in high stress career fields are fit and stable enough to perform their duties, and provides them with help or advice if they are deemed unfit. (U.S. Air Force photo by Airman 1st Class Kate Thornton/Released)