In order to develop and maintain a strong core it is essential to first understand the muscles that make up that region of your body and what types of exercises work each specific section. While your abdominal muscles are relatively small in comparison to other skeletal muscles the core section of your body, as a whole, is quite large. Your core region is complex and composed of many different muscles, both in size, shape and function.
The core region of your body consists of your entire trunk which includes everything from your pectorals (chest muscles) and back all the way down to your glutes (buttocks).
Paring it down further the abdominal section of your core consists of the following four regions:
Rectus Abdominis - this is what is known as the "six pack." It is the most superficial muscle group of your abdominal core area - it allows you to flex and bend your spine. This muscle group also helps to stabilize your pelvis for any type of walking or running movements.
Transverse Abdominis - these muscles are the deepest set of muscle fibers in your abdominal wall. This area of the abdominal wall acts like a belt and helps compress the abdominal contents. You also use this muscle group when flexing and bending.
Internal and External Obliques - these are the muscles on the sides of your core and can actually function independently. When they function independently, they serve to rotate your trunk and laterally flex your body. When both sides contract together at the same time, they help with flexion of your spine and compress your abdominal wall.
It has also been suggested that strong internal obliques are essential in maintaining good low back health because the internal and external oblique muscles attach to the erector spinae muscles and aid in pulling your trunk laterally. If this attachment is strong, and the muscles on either side are strong, your spine will be supported better and movements involving rotation of the trunk will be more efficient. Therefore, strong oblique muscles improve lower back health.
Erector Spinae- while these muscles are not actually abdominal muscles, they are the main muscles involved in back extension. This group of muscles begin at your neck and extend down to your lower back. Any training of your core must include these important lower back muscles as they greatly aid trunk stability, agility and strength. These are the muscles that allow you to pick up and hold heavy objects in front of you, and to stand tall while doing so.
Now that you know the muscles involved, discuss with your trainer how best to work them to get the most "bang for your buck" and to create a strong and stable core region.