from the Mayo Clinic
"A well-balanced core exercise routine focuses on more than your abs. Did you know that your core is where all movement in your body originates? Core exercises are an important part of overall fitness training that, except for the occasional sit-up or crunch, are often neglected. Core strengthening requires the regular and proper exercise of your body's 29 core muscles. Body position and alignment are crucial when performing core exercises. When you get started it is a good idea to have a fitness trainer or physical therapist help you perfect your techinique. For the full story click here.