The abdominal muscles (abs) provide movement and support to your core area.
The deeper and closer to the spine the particular abdominal muscle is, the more effect over body posture it will have, and this often contributes significantly to a healthy back.
Many people put a lot of focus on working their abs but forget their surrounding neighbors; the oblique muscles.
Obliques serve as stabilizers, and are used in almost every physical activity.
Exercising your obliques should be a very important part of your workout program.