
Inner-core conditioning or core training has become an overused word in both the world of the athlete and the weekend warrior. Most people use the word frequently and don’t fully understand what the inner-core is, how to assess it or how to properly train or strengthen it.

So before we go any further let’s define what the “inner-core” is. Quite simply it is the group of muscles that make up the abdominal wall. This includes the following muscles.

The rectus abdominis, which is the muscle that people traditionally think of when they hear abs, it is the washboard, six-pack part of your abs. It attaches from the bottom of your sternum to the bottom of your pelvis and is normally grossly overworked by people because of its ascetic value.

The internal oblique abdominals is an internal abdominal muscle that is on both of your sides, extending from the bottom ribcage to the top of the pelvis. It is an important muscle in trunk rotation.

The external oblique abdominals is the largest abdominal muscle and it lies over the internal oblique attaching to the lower 8 ribs, the top of the pelvis and surrounding fascia (connective tissue). It works together with the internal oblique to rotate the trunk.

The transverse abdomninis (TVA) is another internal abdominal muscle that lies beneath the rectus abdominis, the external oblique, and the internal oblique. It is possibly the most important and least understood of the abdominal muscles because it is difficult to train properly, it acts as a natural weight belt, and it works in series with other core muscles so if the TVA isn’t working, neither are other important core muscles.

The muscles of the pelvic floor line the pelvic floor and support organs, including the bladder, and they contribute to intra-abdominal pressure (that natural weight belt I mentioned).

The multifidus muscles are many small muscles attached to the spine that help support and move the spine and trunk.

The erector spinae are large muscles that line the spine which help support and bend the spine.

The diaphragm is a sheet of muscle at the bottom of the thoracic (chest) cavity that helps with breathing, and contributes to intra-abdominal pressure (that natural weight belt again).

And the thoracolumbar fascia is a deep membrane of connective tissue that attaches to the spine and covers deep back muscles. It is a very important part of intra-abdominal pressure (your natural weight belt) because it is the link between the TVA and the spine.

## Muscles that make up the core

To properly assess the inner-core one must first have a thorough understanding of where these muscles attach (origin and insertion or in other words where the muscle begins and ends), how they are controlled neurologically (innervation or what nerves control them), and their action (what happens then the contract concentrically, eccentrically and statically, or what happens when they move in different ways). It is also important to understand the dynamic relationship between these muscles and how dysfunction in one or more affects the rest of the musculoskeletal system.

Note: the origin of a muscle is the attachment point that stays still when a muscle contracts, and the insertion is the point that moves when a muscle contracts. In most cases, the origin is closer (proximal) to the body and the insertion is further (distal).

## Your built in support belt

Let’s begin with the abdominal muscles. The deepest abdominal muscle is the transverse abdominis (TVA). This muscle’s origin is the bottom of the ribcage, lumbosacral fascia, anterior 2/3rds of the iliac crest and the lateral half of the inguinal ligament. In other words it attaches to the bottom of the ribcage, the major connective tissue of the back, the front 2/3rds of the top of the pelvis, and the outward edge of an important ligament in your pelvis.

The insertion of the TVA is the aponeurosis of the posterior and anterior rectus sheath and the conjoint tendon to the pubic crest and the pectineal line. In other words the TVA inserts into the middle line of one’s abdomen.

The action of this muscle is to draw the abdomen toward the lumbar spine, or sucking in your belly, thereby increasing intra-abdominal pressure and giving support to the abdominal wall. The TVA creates a hydraulic pressure in the abdomen by compressing the viscera (organs) and alleviating pressure from discs in the spine. It also aids in stabilizing the lumbar spine.

Many people do not know how to properly activate this muscle; in fact some push their abdominal wall outward, which destabilized the lumbar spine, thereby increasing their risk for spinal injuries. This is why I advise against the use of lumbar support belts, they cause a person to push against the belt, which weakens their TVA.

### How to assess proper function of the TVA

When a person bends forward to lift an object from the ground the TVA should draw the umbilicus (bellybutton) in towards the spine. If you watch a person while they perform such a lift and place one hand on their back and the other on their abdomen, you should feel the umbilicus drawing inward as they perform the task. If you feel or see the umbilicus pushing or moving outward (away from the spine) then they are not able to activate or properly contract the TVA.

### Strengthening the TVA

There are a few different ways to strengthen the TVA. The easiest way for a beginner is to get into a 4-point stance (on your hands and knees), so that gravity can assist you in figuring out how to expand your abdomen properly.

One of the biggest challenges in teaching one how to activate the TVA is teaching them how to breathe properly. The proper way to breathe is through the use of the diaphragm. If you use the diaphragm to breathe you will expand your abdomen while inhaling, and then draw the abdomen inwards when exhaling. Most people draw their chest up when they breathe because they have forgotten how to breathe diaphragmatically.

So, then in a 4-point position be sure to let the abdomen expand towards the ground when inhaling. Upon exhalation picture your stomach emptying its air and draw the umbilicus deeply inwards towards your spine.

Be careful to maintain a normal curvature of your lower back. If you lose the curvature of your lower back when drawing your belly button in it means you have contracted the lower rectus abdominis and external oblique muscles.

Once certain that you are doing the exercise properly just continue to take slow deep breaths in as you expand your belly and as you exhale draw your belly button inward. Repeat this exercise for 10 to 30 repetitions and perform every other day.

## The six pack

Next we will discuss the infamous rectus abdominis. This is the muscle you see or picture when you think of the “six pack abs” which has been drilled into our subconscious minds as something we must have to look “sexy”.

The attachment points of this muscle are the bottom of the sternum (xyphoid process) and costal cartilage of ribs 5-7 superiorly and at the inferior end the pubic symphysis, pubic crest and pubic tubercle. In other words it goes from the bottom of your sternum and the ribs close by, to the bottom of the pelvis.

The origin and insertion points switch depending on which point is fixed and which is moving.  Many people will attempt to work-out their “lower abs” in an attempt to target the lower fibers of this muscle. However, most people do not perform these advanced exercises properly and end up strengthening the wrong muscles, leading to muscular imbalance, dysfunction and injury.

Furthermore, this is a muscle that is quite often over trained leading to imbalances that present themselves through postural faults, such as increased kyphosis (outward spinal curve in the mid-upper part of your back) and flattening of the lumbar lordosis (inward spinal curve of your lower back).

### Assessing the rectus abdominis

This muscle is commonly over-trained in some individuals. In others it is very weak. Although the rectus abdominis is one muscle, the lower or upper fibers can be strengthened independently of on another because it is segmentally innervated via the anterior primary rami of T7-12. In other words it has eight nerves running to it from top to bottom that give the muscle segmental control.

You may find that it is fairly common for a person to have strong upper abdominal muscles yet be very weak within the lower abdominal muscles. This is mostly due to improper training in which the traditional crunch is done excessively and the lower fibers are never targeted.

In fact, most people who think they are training the lower abdominals are quite often using their iliopsoas (hip flexor) muscles instead. This type of improper training can lead to many common postural faults that may present themselves as lower back and or hip pain.

So, it is vitally important to do a detailed postural evaluation before prescribing or beginning any abdominal strengthening exercises.  The way to assess the strength of this muscle is to have one lay on their back. Have them bend the knee and place their feet into the examiners hands with their toes pointing as if they are pushing on a gas pedal. While exerting slight downward pressure with the feet, have them attempt a sit-up. Have them begin with the arms straight and pointing down towards their feet.

If the feet lift up as the sit up is performed, or they are unable to perform the movement, this indicates weakness.

If they are able to perform the sit up with the arms in this position then the next level would be to perform the test with their arms crossed over their chest. The same parameters apply.

The most difficult level for this strength evaluation would be to attempt the movement with their elbows out to the side of the head with their fingers touching behind the ears. Don’t allow the exerciser to clasp their hands behind their head.

### Strengthening the rectus abdominis

The best way to strengthen the rectus abdominis is by using a swiss ball. By lying on your back over the top of a ball in the supine position (on your back) you will be able to work the rectus abdominis throughout its entire range of motion.

When sit-ups are done from the floor or a bench, there is never any extension in the movement. The average extension is 30 degrees, so if you aren’t extending the lumbar spine (lower back) while performing a sit up you aren’t exercising the muscle throughout its entire functional range.

To be certain you are getting full extension make sure your tailbone, entire spine, and head are resting on the ball to begin the sit up. In the same way the intensity was increased for the testing and evaluation of this muscle, the position of the arms and hands can be used to vary intensity for this exercise.

### Assessing the oblique muscles

There are a variety of ways to evaluate proper balance and function of the internal and external oblique muscles. For this article we are going to focus on using a side lying position over a swiss ball to evaluate balance and strength ratios of the external vs. internal oblique muscles.

This evaluation requires that the feet are stabilized by either another person or a wall as so.

The patient/client should place their hip at approximately the 10:00 to 11:00 position on a ball with their legs split with either the top or bottom leg in the forward position. With the feet stabilized by either the evaluator, another person or a wall, the person is asked to lie over the ball and then attempt to bend laterally (sideways) elevating their head and shoulders while approximating their lateral ribcage to their iliac crest. In other words they should lay on their side and try to do a side crunch without twisting to either side, moving their ribcage to their hip. The position of the arms can either be crossed in front of the chest, or the fingers can be placed so they touch behind the ear and the elbows point outward.

What the evaluator needs to look for is, whether or not they can perform the movement, and if they can, is their body rotating anteriorly or posteriorly (to the front of back) while doing the movement?

The action of the external oblique muscle when acting unilaterally as in this movement is to laterally flex the spine and/or to contralaterally rotate the spine. In other words the external oblique muscle works on the same side of the movement when doing a side crunch. It also works on the opposite side of movement when rotating, so if one rotates to the right, the left external oblique muscle is being used.

The action of the internal oblique muscle when acting unilaterally is also to laterally flex the spine, but ipsilaterally rotate the spine. In other words the internal oblique muscle also works on the same side of the movement when doing a side crunch. But, unlike the external oblique, it works on the same side of movement when rotating, so is one rotates to the right, it is the right internal oblique that is contracting and being used.

So if lateral flexion is being performed correctly there shouldn’t be rotation occurring in either direction because these muscles are in balance with one another.

If the exerciser is laterally flexing towards the right with their left side down on the ball and they rotate their upper body to the right when performing the exercise, this indicates a weakness of the right external oblique relative to the right internal oblique. So the right external oblique is overpowering the right internal oblique.

If they laterally flex to the right with their left side down and their upper body rotates to the left while performing the movement, this indicates a weakness of the right internal oblique relative to the right external oblique. So the right internal oblique is overpowering the right external oblique.

When performing the exercise into left lateral flexion with the right side down, the exact opposite indications would hold true.

### Strengthening the oblique muscles

An effective way to strengthen these muscles and create balance between the internal and external obliques is to perform the exercise just as the movement is performed in the assessment.

If there were weaknesses or imbalances noticed then it is important to guide the patient/client through proper form while performing the exercise by not allowing them to rotate to either side. If they are new to training their obliques or if they are overall weak in this movement they can perform the exercise with their arms crossed over their chest. Also, they can change the position of their downside hip on the ball. The lower the hip is on the ball the easier the exercise becomes.

## Final thoughts

Hopefully now you have a better understanding of what the “core” is, what muscles it involves and how to effectively train each one. With each of these exercises it is very important to know if you are able to perform them properly with good form. At my chiropractic office, this is one of my top priorities when training people.

If you aren’t sure, I would suggest you seek out a qualified CHEK practitioner. You can find one by going to http://www.checkconnect.com.com/app/findpractitioner and looking for someone in your area. Or is you would like to come to my office to be trained, check out my exercise page for more information.

For more information and a demonstration of most of the exercises described here, check out this video we made.

Remember that form is extremely important and you should never sacrifice form for intensity. As with any exercise you must work your way up in terms of repetitions, sets and intensity, making sure to always have impeccable form.

Also, your abdominal muscles are no different than any other muscle group that you train. They should be given proper rest periods between exercise days. A strong, properly functioning inner-core is essential proper stabilization of the lumbar spine and for any movement pattern made throughout the body. With a strong functioning inner-core the athlete, weekend warrior, or regular person doing housework will avoid injury and perform better!


exercise

Peak Performance Abdominal Training

Become a subscriber today!