Core Training has become a popular term in the fitness world and with good reason. Many of the exercises you would normally do can fall under the category of Core Training. Your core muscle are muscles you cannot see; muscle like the Transverse Abdominus, Rectus Abdominus and Internal Obliques.
These muscles give you the ability to stand upright; they support your spinal column and are involved in most every move you make. It is said that you get strong from the inside out, having strong muscles supporting you is the key to having balanced whole body strength.