Core muscles
Core muscles are the muscles around your trunk and pelvis that help control and support your body during movement. The term includes more than the abdominal muscles at the front of your body.
In everyday words
Your core muscles contribute when you reach for something, turn your torso, or carry a bag. Core exercise can involve coordinated work by the abdomen, back, and muscles around the pelvis.
What to keep in mind
Core strength is one part of movement. The term does not mean you should keep your abdomen tightly braced all day or assume that every back symptom comes from a weak core.