Marines and international competitors receive instructions about sitting volleyball prior to the start of their practice session at the Marine Corps Trials. The Marine Corps Wounded Warrior Regiment enables wounded, ill, or injured Marines to focus on their abilities and to find new avenues to thrive. The fourth annual Marine Corps Trials is being held at Marine Corps Base Camp Pendleton, Calif., March 4-12. Athletes will compete in archery, cycling, shooting, swimming, track, field, sitting volleyball, and wheelchair basketball.