Machine gunners fire M240B machine guns and M2 .50 caliber machine guns from the turrets on Mine-Resistant Ambush Protected All-Terrain Vehicles during live-fire squad maneuver training, Oct. 23, 2017, at an undisclosed location. (Cpl. Timothy Valero/Marine Corps)
Airman 1st Class Nicholas Castellucci, 724th Air Mobility Squadron member, flips a tire with his teammates during the first Combat Warrior Challenge at Aviano Air Base, March 14, 2017. The four-day competition included obstacles such as a wall climb, tire flip, and kettle bell carry. (Senior Airman Cory W. Bush/Air Force)
Marines conduct physical training aboard the dock landing ship USS Oak Hill in the Atlantic Ocean, Nov. 30, 2017, during a training exercise to prepare for an upcoming deployment. (Staff Sgt. Dengrier M. Baez/Marine Corps)
A U.S. Air Force C-17 Globemaster III aircrew from the 816th Expeditionary Airlift Squadron unloads high-mobility multipurpose vehicles during combat airlift operations at an undisclosed location. (Tech. Sgt. Gregory Brook/Air Force)
Soldiers assigned to 1st Squadron, 11th Armored Cavalry Regiment, assault an objective during Decisive Action Rotation 18-02 at the National Training Center in Fort Irwin, Calif. (Spc. Daniel Parrott/Army)
