U.S. Air Force Staff Sgt. Cristina Sullivan, 633rd Force Support Squadron Back 2 Basics lead instructor, demonstrates an exercise during a B2B class at Langley Air Force Base, Va., Jan. 8, 2015. B2B is an eight-week fitness program designed to be a lifestyle change, not a temporary diet or fitness regimen. (U.S. Air Force photo by Senior Airman Kayla Newman/Released)