Combat Fitness Challenge participants help setup obstacles before beginning the competition held at the fitness center track on Seymour Johnson Air Force Base, N.C., March 30, 2013. Some of the challenges included a 100-meter dash while performing a fireman's carry with a sandbag and a 100-meter dash while carrying two ammo cans full of water. (U.S. Air Force photo by Airman 1st Class Brittain Crolley/Released)