Related Clues:

• Gym rat's 'six-pack'
• Blood groups
• Rock-hard ones might be a turn-on
• Sit-ups' targets
• Sit-up focus
• They're crunched in a workout
• Braking sys
• They're ripped on some calendars
• Bowflex target
• Muscleman's asset
• Chiseled muscles
• Muscles worked by sit-ups
• They may be sculpted
• Stomach 'six-pack'
• Muscles in the gym