Tech. Sgt. Mary Nelson, 22nd Aeromedical Squadron optometry clinic NCO in charge, performs lunges as part of her daily workout at the fitness center here March 31, 2011, at McConnell Air Force Base, Kan. After having her first child, Sergeant Nelson, who previously scored in the "excellent" category on her physical fitness tests, had to rebuild her core muscles to maintain this precedence. (U.S. Air Force Photo/Senior Airman Abigail Klein)