U.S. Air Force Reserve airmen from the 315th Airlift Wing, Joint Base Charleston, S.C., participate in core strength portion of the physical fitness assessment here, Feb. 5, 2022. According to new regulations, airmen have the choice between traditional sit-ups, cross-legged reverse crunches or planks for the core strength portion of the test. (U.S. Air Force photo by Haley D. Phillips)