A female soldier holds a machine gun

U.S. Army SPC Sheena Mature hoists a 44-pound section of a 50 caliber machine gun onto a M1 A2 Abrams tank during a physical demands study, Tuesday, Feb. 25, 2014, in Ft. Stewart, Ga. The Army is conducting a study that will determine how all soldiers _ including women, for the first time _ will be deemed fit to join its fighting units from infantry platoons to tank crews. (AP Photo/Stephen B. Morton)