The Core

The Core

core strength

This is definitely one of the most talked about concepts, not only in the physiotherapy world but within the sports and fitness industry in general. The core also remains a mystery to most people. We all hear about how we need to strengthen the core, engage the core, activate the core, but what is this core we all keep on hearing about?

What is the core?

We define the core as a set of muscles that attach mainly to the spine and pelvis, and provide stability to the shoulder, hips and trunk of the body. The main function of the core we are concerned with is that of stability which we will discuss later.


Muscles can be divided into two groups, stabilizers and mobilizers. Stabilizers are muscles that have as the main function maintaining the alignment and correct posture during activity, while mobilizers or movers have the function of performing the movements. It is important to note that all muscles have some level of stability function and therefore can be both a stabilizer or a mobilizer. Please note that this is a very simplistic explanation of muscle classifications, but for the purpose of our article we will divide muscles of the core into stabilizers (S) and mobilizers (M) based on the muscle’s primary function.

The main muscles of the core are the following:

  • The diaphragm (M) – the main breathing muscle
  • Transversus abdominis or TA (S) – corset shaped muscle that surrounds our abdomen
  • Multifidus (S) – a series of deep muscles of the back located on the spinal column
  • Pelvic floor muscles (S/M) – a group of muscles that support our pelvic organs
  • Lumbar part of the Erector Spinae (M) – a group of muscles running from the pelvis to the neck
  • Internal obliques (S) – abdominal muscle
  • External obliques (M) – abdominal muscles
  • Rectus abdominis (M) – this is the famous 6 pack muscle

Peripheral core muscles

These are muscles that are peripheral to the main core area, but that play a role direct or indirectly in the function of the core. This includes muscles of the neck, shoulders and hips, such as:

  • Latissimus dorsi (M)
  • Trapezius (M)
  • Cervical and thoracic erector spinae (M)
  • Gluteus maximus (M)
  • Hamstrings (M)
  • Hip adductors (M)
  • Hip abductors (M)

Function of the Core

As mentioned above, the main function of the core muscles is that of stability. Core stability can be described as the ability of the core muscles to maintain optimal spine and pelvic alignment, this is especially important during movement. This optimal alignment is achieved when the muscles involved activate and fire in the correct patterns, thus allowing the load to spread in an even and balanced manner. When the load is spread unevenly, overloading one area more than the other, pain and injury occur.

This ability to maintain optimal alignment, is directly linked to intra-abdominal pressure. Optimal intra-abdominal pressure ensures that the core can withstand load from the rest of the body, as well as from movements and even weights, without sustaining injuries. This pressure assists in the correct position and posture of the spine, pelvis, muscles and joints in the area, and in turn, the correct activation of position and muscle activation ensures there is ideal intra-abdominal pressure. This is the reason why breathing and pelvic floor integrity are so important for core stability.

A great illustration of the core is that of a can. When a can is still sealed with it’s contents it can withstand great load and forces, while if it is empty, leaking, it succumbs to external pressure. So it is with the core, the diaphragm forms the top of the can, the pelvic floor the bottom while the rest of the muscles are the sides of the can. A balance in the activation and correct firing of those muscles allows for the body to endure load, such as is needed in sport and exercise performance.

Another important factor to note is that in dysfunction, the stabilizers tend to fire slower or in the wrong pattern, this in turn,  leads to the mobilizer muscles to take over the stability function and become overactive. This is what we may refer to as a muscle compensation.

The core’s other functions are:

  • To transfer load forces through the body and between different extremities;
  • Increase the efficiency of the load transfer so that we can have stronger and more powerful movements engaging the whole body;
  • Assist in supporting the our axial skeleton (skull to tailbone);
  • Resist the forces of gravity and maintain our position or balance, therefore preventing falls;
  • Assist in the coordination of movement, between upper body and lower body, as well as the left and right side of the body;
  • Plays a key role in childbirth, reproductive, as well as, bladder and bowel function;

Core Strength tests

A few of the core strength tests are:

The push up test – Attempt to do a push-up, keeping your head, neck, spine and pelvis in alignment. A belly drop of curved back are signs of compensation due to poor core strength.

Plank test – Perform a plank, with your hands, elbows and shoulders in line, maintaining correct spine alignment. Hold for 1 minute. The plank can be done as a normal plank or a side plank to test different components of the core.

It is important to make sure you are able to breathe while performing these exercises and that the correct muscle firing pattern is used. Your physiotherapist or trained exercise professional should be able to assist you with the correct posture and firing pattern during these exercises.

How to activate your (abdominal) core?

  • Lie on your back with your knees bent, make sure you support your neck and keep a neutral spine;
  • Place your feet hip width apart;
  • Use your index and middle finger and place it on top of your pelvic bone (love handles), then move them about 1-2 cm centrally (towards your belly button);
  • Then imagine tightening a band around your abdominal area, you should feel the light pressure of a balloon filling under your fingers.
  • If you are unsure of what to feel, try activating your pelvic floor muscles, imagine you are in a queue to use a toilet in a public place and have to hold your pee in. That light pressure that you feel under your fingers, is the pressure you are looking for when you activate your abdominal muscles.
  • You should be able to breathe normally while you perform this exercise.

Practice activating these muscles a few times a day, and then practice holding the activation progressively more, until you can do other activities and even exercise while engaging your core.

This is just one way of activating your core muscles. There are many different ways of activating these muscles and retraining them, as well as different cues that may be used. This is why it is important to seek someone who has been trained to assist and guide you in your core retraining.

Benefits of core stability

  • Reduced pain, especially incidence of Lower Back Pain (LBP)
  • Reduced risk of injury
  • Better posture and movement mechanics
  • Improved balance and coordination
  • Improved muscle strength and stability
  • Improved joint stability
  • Improved gastrointestinal, sexual, bladder and bowel functioning
  • Improved athletic performance

We hope you find this article helpful in shedding some light into what the core is and its functions. As you can see, the core plays an integral part of our normal movement and activities and much more. This is the reason almost every physiotherapist, biokineticist and trainer will assess your core, and integrate core activation into your training plans. If you have any further questions or enquiries, do not hesitate to contact us.

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