Capt. David A. Keltner, the assistant operations officer at the Adviser Training Cell with I Marine Expeditionary Force, does atomic push-ups during a fitness challenge at the 21 Area Fitness Center ...
Cyle Brewer, a member of the Copperas Cove Special Weapons and Tactics team, pushes himself during the TRX training circuit at the Applied Functional Fitness Center at Fort Hood, Texas, Dec. 16, 2015.