Related Clues:

• Core features
• Pulldown muscles, for short
• Washboard __
• Core workout targets
• Muscles in a six-pack
• Muscles in 'packs'
• Situp muscles
• Short muscles?
• Six-pack contents?
• Stomach muscles, familiarly
• Targets of leg raises, informally
• Beneficiaries of exercises called Russian twists
• Back muscles, in gym slang
• Prominent features on firefighter calendars
• Torso muscles