Related Clues:

• Muscles worked by pull-ups, briefly
• They're strong when ripped
• Planks work them
• Washboard from working out
• Pulldowns work them, for short
• Flat 'six-pack'
• Back muscles, in brief
• Core components
• Core muscle group, briefly
• Crunch target
• The pack in a six-pack
• 'Rock-hard' muscles
• Many admire ripped ones
• Muscles worked in sit-ups
• Eight-pack makeup