The muscles of the core are primarily those of the trunk and pelvis. The core muscles stabilize the spine and effectively move the body with varying loads. If the trunk muscles are weakened, then posture and movement can be affected significantly. It is believed that training for core strength and stability can lower the risk of injury and increase power application for sports performance.

Strengthening the core muscles of the trunk and pelvis provides a stable platform for the actions of the shoulder, arm and leg muscles. Emphasis should be placed on diagonal and rotational movements, and promoting balance and strength by performing exercises standing or sitting on different (including unstable) surfaces such as balance beams, bosu, foam rollers, and stability balls. Some of the most important muscles of the core are the deeper abdominal muscles that wrap and protect the spine; the abdominal muscles that run along the front and sides of the abdomen; the erector muscles of the lower back; and the muscles of the pelvic floor and hips.