Staff Sgt. Rodane Williams from the 919th Special Operations Maintenance Group strains while doing leg raise warmups at a GoRuck Challenge event May 12, 2016 at Duke Field, Fla. The teambuilding exercise, based on special operations fitness training, put participants through a five-hour series of physically and mentally exhausting scenarios along an eight-mile ruck march. (U.S. Air Force photo/Dan Neely)