Related Clues:
- Workout goal, perhaps
- Cookie ___ (certain Ben & Jerry's center)
- Reactor ___
- Parts of a six-pack
- Sailor's muscles?
- Pilates workout focus
- Centre set up in Little Rock
- Some are rock-hard
- Inhalation assistants
- Core part, informally
- Plank targets
- Center of the Earth
- Internal stabilizers
- Planking targets them
- Muscles worked by Russian twists