So What Exactly Is Your Core?!

Training your core with back extensions

The word ‘core’ to describe your mid-section is thrown around abundantly in the fitness world. You won’t go into a gym today without hearing personal trainers talking to their clients about their core muscles or you won’t be far from someone on Instagram showing you how to improve your core function.

But if someone were to ask you what in fact your core muscles are would you be able to answer them? Perhaps not.

In this post I will explain a few things:

* What your core muscles actually are.

* What function they perform.

* How to consciously activate them.

* What benefit a strong core is to exercise, training and everyday life.

So What Are Your Core Muscles?

The core is an area that extends from the bottom of your rib cage to your pelvis and connects your upper body to your lower body.

It can be thought of as a cylinder that encircles the body between your chest and your legs. There are muscles that overlap and ring the body in a circle and there are muscles that run longitudinally up and down the body, front and back.

They all need to function together and work properly in order to provide you with a strong foundation and anchor point for your movements.

Your core is the foundation of all your strength and the cornerstone of athletic ability, good posture and prevention of injury.

So what muscles are involved?

1) Transverse Abdominus

Transverse Abdominus TVA muscle

The deepest of the core muscles, the TVA as it is also known, gets its name from the direction of its muscle fibres. They run transverse or horizontally around the trunk. This provides a deep stabilizing action on our mid-section. It is also called the ‘corset’ muscle as it helps draw the stomach in and flatten it out like having a corset or tight belt around your middle.

It is therefore better to train this muscle using exercises such as hollow body holds, plank variations and the more advanced levers in order to gain a flatter stomach rather than performing abdominal crunches as these target the rectus abdominus muscles (see below) that if anything will only extend the stomach further out if over developed.

The TVA also aids in inhalation as it is connected to the diaphragm. In movement and exercise it helps provide pelvic and spinal stability and is therefore very important. It has been estimated that vertical pressure on the discs of the spine can be reduced by as much as 40% with proper TVA activation and strengthening.

2) Internal Obliques

Internal oblique muscles

The internal obliques are the ‘middle’ muscles of the core as they lie on top of the TVA but below the external obliques.

They connect at the ribs and pelvis. We have one on either side of our trunk and they have two functions.

When they contract they compress the organs of the abdomen, pushing them up into the diaphragm, which causes the chest to decrease in size and leads to an exhalation of air.

Secondly, they are responsible for the rotation and side bending of the trunk in conjunction with the external obliques.

3) External Obliques

External oblique muscles

The external obliques lie on top of the TVA and internal obliques. They are larger than the internal obliques and work together with their opposing counterparts to achieve torsional movement of the trunk.

For example, the right internal oblique and the left external oblique contract as the torso flexes and rotates to bring the left shoulder towards the right hip. It also pulls the chest downwards and compresses the abdominal cavity.

4) Rectus Abdominus

Rectus abdominus or 6-pack muscle

The Rectus Abdominus is the ‘6-pack’ muscle or the muscle that everyone generally trains when they want a flat stomach.

It is a paired muscle with two parallel muscles running down either side of a band of connective tissue known as the linea alba.

It runs from the sternum down to the pelvis and is responsible for flexing the spine as when doing a traditional ‘crunch’ It also plays a role in breathing and creating intra-abdominal pressure such as when lifting something heavy or straining.

5) Erector Spinae and Multifidus

The Erector Spinae is a big bundle of muscles that run up the length of your spine.

It varies in size and shape as you travel up the spine, starting out at your pelvis as a large thick lump and then branching into smaller muscles further up.

Their action is in the extension of the spine (bending backwards), keeping the spine upright and solid and also they play a small part in the rotation abilities of the trunk.

Whilst the Erector Spinae does the global work in supporting and extending the spine the smaller and deeper Multifidus muscles work to keep each segment of our spine and our spinal discs in alignment at a local level.

6) Quadratus Lumborum

Quadratus lumborum muscle

The Quadratus Lumborum (or QL) is a thick muscle that connects your pelvis to your lowest rib.

It is responsible for lateral flexion of the spine and for extension of the lumbar spine.

It is a common area for back pain as it takes over the work when the erector spinae muscles are weak due to prolonged hours sitting down.

7) Hip Flexors

Hip flexor muscles

The Hip Flexors are made up of a collection of muscles; among them the iliacus and the psoas major and minor. Together they are known as the Iliopsoas.

They are responsible for flexing the thigh at the hip joint, that is, bringing the knee up off the floor.

However as the psoas also travels through the pelvis and connects onto the lower spine it can also flex the spinal column and hence can play a part in core stability. Whether it is actually part of the core musculature is open to discussion.

Many of us can spend a large portion of our lives sitting down so these muscles can become very much shortened and so affect how the core area functions.

8) Gluteus Maximus, Medius and Minimus

Gluteus maximus, minimus and medius muscles

The glute muscles are another muscle group that are not generally associated with the ‘core’ group but are nonetheless very important.

They are the bodies biggest muscles, are very important in posture and movement and are typically weak in most people. Working on these will provide a good platform on which to build a strong core.

9) Pelvic Floor Muscles

Pelvic floor muscles

The pelvic floor muscles provide the base of the core musculature and work with the TVA, back muscles and diaphragm to support the spine and control the pressure in the tummy cavity.

When we exercise, especially lifting weights or other movements where we need to hold our breath and brace, the pressure in that cavity (known as intra-abdominal pressure) increases greatly.

A strong and correctly functioning pelvic floor helps to control this pressure by staying tight and rising up slightly.

If the pelvic floor is weak and we continue to increase our intra-abdominal pressure whilst exercising, over time it can lead to a depression of the pelvic floor and loss of bladder or bowel control.

How Do They All Act Together?

The core muscles function as a group and prepare and react to every movement that occurs with your body.

The timing and strength of the reactions is very important as movement without correct stabilization can place undue stress on the spine and lead to injuries and back pain.

You want these muscles to be strong and working together as a finely tuned unit to provide you with the best possible support during your everyday life. Even a simple movement such as lifting your foot off the floor utilizes the core muscles so you can see how important they can become in more complex movements.

Picture the rib cage and diaphragm as two concentric circles one outside the other. The core muscles are arranged between these circles and are trying to keep them in alignment.

With a strong, correctly functioning core musculature the circles have support the entire way round, like the sides of a can and top to bottom, front and back too. You can see how this set up would provide excellent support for the two circles and stop them moving too independently of each other.

If the core muscles are weak or not functioning correctly this support is lost and we begin to get movement of the two circles.

Now picture the two circles with just a strip of muscle running from top to bottom at the front and imagine how well aligned the circles would be during movement. Not very. There would be a lot of scope for the circles to move independently of one another.

This is what can happen when we only focus on our ‘six-pack’ muscle, or rectus abdominus, by performing an endless amount of crunches.

We over develop that front strip of muscle at the expense of all the others.

How To Activate Your Core Muscles

Activating your core muscles properly is more than just tensing your stomach. If your core muscles are weak or inhibited all you will be doing is tensing your rectus abdominus.

It is very important to learn how it feels to activate your core muscles so you can consciously turn them on and off during exercise.

There is a huge difference in difficulty between doing a core exercise with your core muscles activated and doing the same exercise without them activated.

  1. Lie down on your back on a firm surface and place your two fingertips on your abdomen, about 5cm in from each hipbone.

  2. Breathe in fully and then slowly exhale all the air in your lungs.

  3. As you empty your lungs fully and forcefully expel the last of the air you should feel some muscles tighten under your fingertips and your tummy flatten out. They are your inner core muscles.

However, what you might find is that your tummy domes upwards. This happens because your six-pack muscles are engaging too quickly.

Or you might not notice anything, meaning that your core muscles are weak and not performing properly.

Try lifting one leg up off the floor. Do you notice anything under your fingertips then?

Again your core muscles should become activated and you should notice a tightening and flattening of the tummy.

Three other ways of learning to activate your core muscles:

  1. It can help sometimes to contract your pelvic floor muscles first (like you are trying to stop yourself from urinating mid-flow!) and then try and contract the muscles above these too. Always remember to keep breathing normally. Your pelvic floor muscles are in fact very important to providing support during exercise.

  2. Try lying on your front. Without arching your back, lift your belly button upwards towards your spine so a gap is created between your belly button and the floor. This uses your inner core muscles too.

  3. Stand against a wall with your heels, glutes and head all touching the wall. Flatten your back fully against the wall including your lower back where there is usually a natural curve. This requires you to ‘scoop out’ your tummy or pull the belly button inwards toward your spine. Hold this position whilst breathing normally and gradually increase the time you can hold it for. The core muscles are holding your tummy in.

It can be a hard concept to grasp if you haven’t used your core muscles correctly for some time.

Keep practicing with the breathing and control aspect of the above exercises and try to feel for that change under your fingers. Once you can feel the core muscles tighten and with a bit of practice you should be able to replicate that action at any point and in any position.

Once you are comfortable achieving this activation you can then try it during your training.

Even exercises that appear simple such as lying leg raises will provide a challenge when the core is activated properly.

What benefit is a strong core to exercise, training and everyday life?

As we get older the majority of the population becomes more sedentary, busy with work and family and not doing enough exercise.

Sitting down all day, which a lot of people have to do for work, leads to your core switching off, becoming weaker and not carrying out the tasks it is responsible for. Then when you do start exercising or even have to lift something heavy, move fast or twist round awkwardly in everyday life, your body pays the price for not being able to support itself as it should. You get injured.

Quite simply a strong core will provide a safer training experience.

Once you learn how to efficiently and quickly turn your core muscles on (it will get to a point when you no longer have to consciously do it – it will happen naturally) you will be less prone to injury, you will be able to lift more, your exercises will be more effective and you will see that flatter tummy quicker!


For a more detailed description of how a strong core plays an important role in the most popular boardsports see my blog post here.

If you are interested in how my online coaching programme for boardsports could help you get in shape for an upcoming trip or just so you are ready the next time you hit the water or slopes take a look at the information on the rest of my website.

#core #coremuscles