SHOULDER BOULDERS U.S. Marine Corps Lance Cpl. Donald F. Marshall struggles to hold two 30-pound ammunition cans on his shoulders as he walks from the obstacle course near Ironworks Gym to the Penny Lake athletic field, which is a distance of nearly a mile, to then complete a combat fitness test on Marine Corps Air Station Iwakuni, Japan, June 17, 2009. Marshall was competing for a chance to ride in the back seat of an F/A-18 fighter jet in an upcoming deployment. SHARE: Download: Full Size (0.05 MB) Credit: VIRIN: 436874-E-CNT58-283.jpg Photo Gallery