Airmen endure demanding physical exercise during a Pre-Ranger Assessment Course at Davidsonville Communications Site, Md., Oct. 7, 2013. Continual physical exercise and endurance is reinforced daylong throughout the course to ensure the Airmen have the required strength if they were to be selected for the 62 daylong Army Ranger Course. (U.S. Air Force photo/Airman 1st Class Erin O’Shea)