Members of the 633rd Security Forces Squadron Emergency Services Team performed a ruck march from Shellbank Fitness Center to Combat Arms Training at Joint Base Langley-Eustis, Va., April 28, 2017. The EST members developed and tested a qualification course, based on the teams abilities to effectively handle hostage and barricaded suspect scenarios, which will be used to assess future candidates looking to join the team. (U.S. Air Force photo/Senior Airman Derek Seifert)