MARINE CORPS BASE HAWAII - Participants push themselves during the Ab Express class at the Semper Fit Center on Marine Corps Base Hawaii, May 23. There are a variety of exercises, working the participant’s entire core, back, legs and also helping their balance.(U.S. Marine Corps photo by Lance Cpl. Janelle Y. Chapman) - MARINE CORPS BASE HAWAII - Participants push themselves during the Ab Express class at the Semper Fit Center on Marine Corps Base Hawaii, May 23. There are a variety of exercises, working the participant’s entire core, back, legs and also helping their balance.(U.S. Marine Corps photo by Lance Cpl. Janelle Y. Chapman)