Related Clues:

• Muscles that are targets of planking, informally
• Ones feeling the crunch?
• Stabilizing muscles
• What your core covers
• Focus for a core workout
• Fitness centers?
• Muscles worked by side planks
• Core muscles, in brief
• "Six-pack"
• Muscles that get 'crunched' in crunches
• Auto safety feature preventing skidding, for short
• Flutter kicks work them
• Word before curriculum or meltdown
• Apple center that produces no iPhones
• Targets of sit-ups