Core Stability. What is it? And why is a weak core bad for low back pain?

By Janet Fabbri & Tash Barry – Physiotherapists


Often we hear the words “switch your core on”, “use your core”, “your core is weak”…but what exactly is our ‘core’? Why is it important? And is there a link between a weak core and lower back pain?

core stability

What is my core?

Your core is a cylinder of muscles that sit around the pelvis and mid-section of your body. These muscles are mostly deep and unseen, and include the transversus abdominus, multifidus, pelvic floor and diaphragm. These are endurance muscles and are used to hold up our body against gravity.. They are our postural muscles and they use Oxygen to fuel them. They work at a low level all the time that you are upright, and they have to work for a long time (all day, unless we are resting). We also have “ Power” muscles in the body which have to be strong and which move the body.

It’s not just the back that has core muscles –  every joint in the body has both types of muscles !

Power Muscles of the trunk

trunk muscles core stability
This diagram shows the Power muscles of the abdomen that sit over the core muscles:

  • Internal Oblique
  • External Oblique
  • rectus abdominus

back muscles core stability
This diagram shows the power muscles of the back.

What does the Core do?

The Core “stabilising” muscles hold the joint/s together to then enable the power muscles, which are more superficial,  to do the heavy lifting. The power muscles fatigue quickly, because they use Glycogen to fuel them and then after this runs out (e.g. after lifting a heavy weight 10 times) they have to refuel and need time for the blood to carry more Glycogen to the muscle. Oxygen is plentiful in the bloodstream and is stored well in muscles, so  “ core “ muscles don’t fatigue very easily.

Injury and pain cause the brain to reduce the activity in the core muscles and actually increases the activity in the power muscles, giving us “Spasm” which is the brain’s way of protecting the area from further damage until it heals. If this continues, however, then a “ weak core” can cause ongoing issues. This is why continuing to move gently when you have lower back pain is essential because we want the brain to learn to reduce the spasm in theses “Protective “power muscles. Fear of moving can occur due to fear of doing further damage. This can happen if you are under lots of stress, which can be unrelated to the back injury. Chronic pain then follows. If someone has a weak core and tries to do heavy power lifting such as Crossfit this can lead to injury and pain. We, as Physiotherapists, see this very often.

So optimal spinal health and fitness requires that the core muscles hold the spine up thus stabilising the joints, while the power muscles can then efficiently move the truck and  also contract strongly in order to lift heavy weights and move you efficiently and strongly. Strength is very important but must be done on a stable base. Your Physiotherapist can assess whether your core is working properly and also see if you are “Bracing “ your abdominal and back muscles excessively, which is when you are overly contracting all of your Power muscles to compensate for the Core muscles not working properly. We can then prescribe individualised exercises to correct this and if done regularly, will improve your core allowing you to perform a variety of exercises to reduce your back pain. Research has found that supervised exercise programs in groups get better results for improving core stability and providing functional and varied strength and flexibility, than doing it on your own, and our Clinical Exercise classes do just this.

It is neuroplasticity in action – repeating the correct movement over time creates mastery of the correct technique and then the brain then makes this “core stability” a habit.
This is one of the secrets to reducing low back pain!

However, our core has gained a lot of popularity over the last decade but more recent evidence suggests it gets a lot more credit than its due! Only doing “Core stability” exercises is not enough to reduce low back pain.

Is there a link between a weak core and lower back pain?

Trunk stiffness, or “bracing” of the spine can occur when the core is not functioning optimally, which is associated with LBP.

Recent studies prove that lower back pain is more likely a result of too much overall abdominal muscle activity which seems to be associated with a weak core. People with LBP tend to brace the abdomen and back Power muscles ( see diagrams above) and have difficulty controlling their mid-section with daily activities such as bending, lifting, and exercising when there is pain. This is done subconsciously by the brain, so many people don’t even realise that it is happening. The brain can learn this pattern and back pain can continue. By learning to move without doing this is what we can help you with, and with practice over time your pain should improve.

(Also see our Insight on “Low back pain. Exercise is Medicine”)

Other known factors that can affect our pain are:

Worrying about our pain, fearing movement, withdrawing from social and physical activity as well as having other things going on in life (stress, poor sleep, inactivity). These factors can be addressed during a consultation with one of our highly trained physiotherapists, to reduce your pain before getting you back to joining in group activities or your favourite sport.

So, do I need to strengthen my core?

Exercise is crucial in managing lower back pain, in more ways than you think. But there’s more to this than sit-ups! In fact sit ups work the Power muscles of the abdomen as well as the core muscles, so if the core is weak and you do sit ups, you may get more pain.

Rather than thinking about strengthening your core specifically, change your focus to moving your body instead!

The correct exercise will help stabilise your core as well as strengthen your entire body, increase your ability to start bending, lifting and twisting. It will also improve your balance, strength, mobility and functional abilities. It also has positive effects for your heart, body and mind, including:

  • Preventing cardiovascular disease, cancer, and diabetes
  • Reducing the symptoms of depression and anxiety
  • Enhancing thinking, learning and judgment skills
  • Improving overall well-being

How much should I exercise?

The World Health Organisation recommends adults between 18-64 years should:

  • Do at least 30 minutes of moderate intensity physical activity daily
  • Muscle strengthening exercises on 2 or more days a week
  • Limit the amount of time spent sedentary (aka sitting at your desk!)

Adults over the age of 65 years should also focus on functional balance and strength training to enhance functional capacity and prevent falls. (See our Strong Bones, Strength 4 Life and GLA:D classes!).

Of course, where a specific dysfunction is present such as incontinence, our trained physiotherapists will provide you with an individual exercise program to target the pelvic floor muscles first and help guide you back to exercise. Our team is also there to appropriately guide you back to exercise following an injury or pain.

What should I do for my lower back pain then?

A combination of specific and general exercise and movement, as well as strategies to reduce any bracing through your trunk, and management of any external factors such as stress, poor sleep and poor diet will help your lower back pain. We recommend you see our physiotherapists who can identify what is causing your pain and guide you through an individualised treatment plan.

So where do I start?

At Higher Function, we have plenty of classes available for you to achieve your goals, including Matwork, Reformer, Semi-Private, Independent gym, Strong Bones, Strength 4 Life and GLA:D classes.

All of our classes are aimed at different levels and aged groups, and with different goals (targeting osteoarthritis, improving bone density, increasing balance and stability, strength etc). Our highly trained Physiotherapists and Exercise Physiologists are equipped with a huge repertoire of quality exercises to help stabilise not just your core, but also to strength and stretch your whole body depending on what your needs are.

We will complete a thorough individual examination to assess your current functional status, prescribe individual exercises to help improve your functional capacity, and then recommend a class that’s the perfect fit for you and your goals. You might even prefer our independent gym option, where you can book in at a day and time that suits you and work through your prescribed program independently.

Get in touch with us today for more information on our classes, or to book an assessment, where you will get the right advice and be on track to a better, healthier you!


Malátová R, Rokytová J, Stumbauer J: The use of muscle dynamometer for correction of muscle imbalances in the area of deep stabilising spine system. Proc Inst Mech Eng H, 2013, 227: 896–903.

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Higher Function Team [email protected]
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