The Core and Lower Back Pain


The Core and Lower Back Pain

If you have ever been to a gym or an exercise class, you are sure to have heard of the “Core”: “use your core muscles”, “strengthen your core”, and “tighten your core”. But, did anyone ever explain to you exactly what the core is? Some people think that their core is just the stomach muscles (the abs). If you are not quite sure what or where the core is, read on.  By the end of this article you will be an expert.


What is the Core?

Think of your core as an old-fashioned corset. It keeps your back straight, your stomach pulled in and you have perfect posture.

Definition of the Core

Diane Lee, a Canadian physiotherapist who specializes in the core, defines it as the area of the body that's located between the diaphragm muscle and the pelvic floor. According to Lee's definition, the core includes all the joints in the pelvis, lumbar spine) and chest. Definitions vary, however, as some experts do not include the pelvic floor.

This means that core muscles are not just limited to the abs, but includes many other trunk muscles. See the diagrams below. That’s a lot of muscles but we are just touching on a few. Your body is amazing, that is one reason why we should keep it in tip top shape.



Before going any further, let’s talk a little about the lumbar spine. The lumbar spine is what we call (in layman’s terms) the lower back. It is made up of five distinct vertebrae, L1-L5, which is the largest of the vertebral column. This supports the lumbar spine in its main function as a weight bearing structure. If you have ever had lower back pain, or are suffering from lower back pain, the problem is most likely located in this specific area. Problems with the muscles and discs between the lumbar vertebrae are what cause lower back pain.


Abdominals (Abs)

So, basically, your core includes your diaphragm, stomach muscles (abs), back muscles and the muscles on the left and right hand side of your torso.

These muscles can further be divided into two groups according to function and attributes, and when considering core strengthening exercises:

  1. Deep Core Muscles – also called local stabilizing muscles. These muscles also provide precise motor control and are primarily responsible for spinal stability. (Core strength training for patients with chronic low back pain; Wen-Dien Chang, PhD, et al)

  2. Shallow Core Muscles – also known as global stabilizing muscles connect the pelvis to the thoracic ribs or leg joints and enable additional spinal control. These muscles produce high torque to counterbalance external forces impacting the spine. This group of muscles is secondarily responsible for maintaining spinal stability. (Wen-Dien Chang, PhD, et al)



You really get an idea of how important your spinal column is when you realize how many different muscles and systems are in place to keep it stable and functioning.

The Core and Your Back

Some of the core muscles are in your back, and some of them run from the neck down to the bottom of your back. Some of them are directly connected to the vertebrae in your back and their main functions are to:

  • Stabilize the entire spine.

  • Produce extension of the vertebral column and rotation of the vertebral body away from the side of the contraction and is active in lateral flexion of the spine.

  • Stabilize and rotate the lumbar spine (see explanation above).

One important physiologic function of the back muscles is to take pressure off vertebral discs and create padding between vertebrae so the body’s weight can be evenly distributed.

These muscles, when they are healthy and uninjured, work together to ensure that you have good posture, can bend forward and straighten up, and can bend from side to side without pain or stiffness. (See the graphics below). They also work with the diaphragm in breathing, especially when you are learning to breathe from your stomach.



This muscle may seem strange to consider a part of the core but it is very important.

The diaphragm is a dome-shaped muscular partition separating the thorax from the abdomen in humans and animals. It plays a major role in breathing, as its contraction increases the volume of the thorax and so inflates the lungs. It is essential in developing good breathing techniques.


 Sam Kidd, coach for the United Kingdom cycling team says that “the diaphragm also has an important role in stabilizing the core. It forms the top of the core ‘box,’ and functions as a secure lid on a strong box.”

The diaphragm is unique in its many bony and soft-tissue attachments. “It attaches directly to the lower six ribs on the inner surface of the rib cage, the bottom of the sternum, and to the lumbar spine,” Jill Miller C-IAYT, E-RYT says (Core Training: Don’t Forget the Diaphragm,

“The diaphragm has a secondary role in core stability,” says Mike Reinold, D.P.T., of Champion Physical Therapy and Performance. “Because it sits at the top of the abdominal cavity, it functions with the abdominal muscles and pelvic floor to provide core stability when braced.”

Without the contribution of the diaphragm, the spine is not fully stabilized and your body has to rely on more peripheral trunk muscles to help out. This limits both spinal stability and efficient transfer of energy, as the peripheral muscles, which are best suited for force production and transfer, are unduly burdened by having to help to stabilize the spine.


The Core and Lower Back Pain

Your core, as described above and positioned where it is, supports both your upper and lower body. It is the centre of your body.

When the core muscles function normally, they can maintain segmental stability, protect the spine, and reduce stress impacting the lumbar vertebrae and spinal discs.

It follows, therefore, that if something goes wrong with your core (the centre), or it does not function at an optimal level, you will notice the effects in some or all parts of your body. However, at this time, we will focus on one of the primary negative effects of a weak core: lower back pain.

The causes of lower back pain, acute or chronic, are complex and some are unknown. However, one major cause involves the weakening of the shallow trunk and abdominal muscles. Reducing or eliminating lower back pain, and improving mobility involve strengthening these muscles. (Wen-Dien Chang, PhD, et al)

Another cause of lower back pain is the weakening of, or insufficient motor control of the deep trunk muscles. Core strength training is directed at training the deep trunk muscles. (Wen-Dien Chang, PhD, et al)

One of the primary aims of core exercise training is to prevent injuries that can occur if you don't properly support the spine, and help to reduce or heal lower back pain where it already exists. Among the key benefits of core strength training are:

1.    Reduction of Back Pain

Abdominals get all the credit for protecting the back and being the foundation of strength, but they are only a small part of what makes up the core, as you can see from above. In fact, it is weak and unbalanced core muscles that are linked to lower back pain.

Weak core muscles result in a loss of the lumbar curve and a swayback posture. Strong, balanced core muscles help maintain appropriate posture and reduce strain on the spine (

Overuse, improper use (improper lifting, for example), and strain of the back muscles are some of the major causes of chronic lower back pain. One typical cause is the habit of sitting at a desk using a reclined seat, which releases the intrinsic back muscles and weakens them in the long term.

Remember that the muscles all work together? If your back muscles are weak they must be compensated for by other muscles (such as the ones in your side), leading to painful tension and stiffening of those muscles. Think of your car with one flat tire: the other three tires will compensate so that you can drive for a short distance to get it fixed or replaced. But that tire will have to be replaced. In the case of your back, the other muscles will support your back for a time, but eventually you will need to see a professional and get help to fix the problem.

Other causes can be direct damage (pulling a muscle) or any type of imbalance of the pelvis or spine. An example of that type of imbalance is unequal leg lengths.


2.    Improvement of Postural Imbalances

Training the muscles of the core helps correct postural imbalances that can lead to, stiff neck, headaches, etc, or injuries. The biggest benefit of core training is to develop functional fitness—the type of fitness that is essential to daily living and regular activities ( Your core has to work throughout the day until you go to bed. The core is always important even when you are sitting down.


How to Strengthen Your Core

There’s no quick or easy way around this; the only way to strengthen your core is exercise; targeted, regular, committed exercise. It sounds boring, it sounds like a chore, but once you get into the habit, and your lower back pain is reduced, and even disappears, you’ll say that it was well worth the time and effort.

Core strengthening exercises are most effective when the torso works as a solid unit with both front and back muscles contracting at the same time. These exercises should be multi-joint movements, and you should monitor the stabilization of your spine.

 Many core strengthening exercises can be done at home with no equipment.

Some of the best cores strengthening exercises are (you’ve probably heard the names or have actually done them):

  • Plank

  • Side Plank

  • Push-Ups

  • Squats

  • Oblique Twists

  • Bird Dog

  • Prone Leg Raises



Stretching is also good for the core as it elongates muscle, making them more relaxed and less stiff, reducing downward pressure on the spine. However good your core is, you cannot escape gravity! These are some of the areas where stretching will produce great benefits: 

Hip flexors: Puts an axial load on the spine when you’re standing. (Think of the weight on the axles of those huge container trucks you see on the highway). Tight hip flexors create a forward pelvic tilt.



Hamstring: Try bending forward with a straight leg. It’s super hard because most of us sit all day. Stretches are very helpful for your hamstrings.



Gluteus medius:  We usually think of the glutes as being only in our bottom, but this one is more on the side in the region of our bottom (see graphic below). The gluteus medius begins on the external surface of your hip bone. It attaches to the iliolumbar ligament (see diagram below) and works in a cross pattern with the opposite back muscles, eg., the gluteus medius muscle on the right attaches to the back muscle on the left.. Make sure these are not tight and that they are functioning. Gluteus medius is a very technical term but hopefully the graphics below will help you to understand where it is located and how it functions.


Core Strength Training

In reviewing research studies, Wen-Dien Chang, PhD, et al, found that core strength training is easier for lower back pain patients to learn, although it is challenging. No special equipment is required, patients can independently practice core strength training at home, and that home-based exercise programs can yield added benefits for motivated patients.

In these studies, four core strength training exercises (i.e., trunk balance, stabilization, segmental stabilization, and motor control) were implemented for training the deep core muscles:

  • Trunk balance exercises are aimed at enhancing patients’ balance by strengthening the trunk.

  • Stabilization exercises emphasize progressive core strength training techniques. It’s not all done at once and will take a series of varied exercises.

  • Segmental stabilization exercises enhance spinal stability by focusing on both the back and abdominal muscles. The Plank is an example of exercising this area.

  • Motor control plays a critical role in stabilizing the spinal system. Maintaining lumbar spinal stability involves three interactive systems: the passive support system, which relies on the ligaments and fascias (they connect muscles to bone) of skeletal muscles; the active contraction system, in which lumbar spinal movement and stability are maintained by contracting the core muscles, and the central nervous system, which plays a leading role in motor control.

In reviewing the research, Chang et al found that although core training and trunk balance exercises are challenging activities, they can reduce disability and pain. These results were confirmed by the use of objective evaluation instruments such as ultrasound to check changes in the both the deep core and shallow core muscles (mentioned above). 

We can safely say that core strength training is very valuable in treating chronic lower back pain.




  2. Sam Kidd, How to Activate Your Diaphragm to Improve Breathing and Performance;

  3. Jill Miller, C-IAYT, E-RYT, Core Training: Don’t Forget the Diaphragm;



  6. J. Phys. Ther. Sci. 27: 619–622, 2015; Core strength training for patients with chronic low back pain; Wen-Dien Chang, PhD, Hung-Yu Lin, PhD, Ping-Tung Lai, BS;