Related Clues:

• Core muscles, for short
• Lumbar spine flexors
• Six-pack to be proud of
• What sit-ups work
• They're below the pecs
• Core muscle group
• "Crunched" muscles, briefly
• "Crunched" muscles
• Hard pineapple part
• Target of some workouts
• Pilates target
• Middle, beginning or end of course
• Part of Apple's casings for computer hardware
• They might be ripped
• Torso muscles, briefly