Philip Hardinger, Doctor of Chiropractic, straps on a parachute attached to an ejection seat in a 307th Bomb Wing B-52H Stratofortress to get a feel for what aircrew experience during a mission, July 24, 2014, at Barksdale Air Force Base, La. Hardinger is studying the effects to help prevent and treat back injuries experienced by crew members. (U.S. Air Force photo by Master Sgt. Greg Steele/Released)