To answer the question, we must first be clear what we are referring to as ‘core’.
When the media, fitness or health professionals talk about the ‘core’ muscles, it may mean one thing to a person and different to another.
The reason for the inconsistency may be due to the desire to keep things simple for layman to understand or we may have learned from different source of authority.
If health professional or media starts using medical or anatomical jargons, clients may switch off mentally. Conversely, it takes time to define the ‘core’ muscles and explain how it affects a person’s lower back (i.e. lumbar spinal section).
In our time-tight society, we are tempted to take the easy way of KISS (Keep It Simple & STUPID). Sure, let’s keep things simple but not over-simplify explanation! I will try my best not to.
First, this is my definition of the ‘core’ muscles. The ‘core’ includes the muscles that make up or extend across the mid-section of our body. The word ‘across’ is important to take note of and this will be evident as we look at the anatomy.
The muscles include the superficial muscles and deeper muscles at the front and at the back. Muscles that are superficial on the front include: External Oblique, Internal Oblique and Rectus Abdominal.
External Oblique (Left)
Internal Oblique (Left)
Rectus Abdominal (Left)
On the back, the Latissimus Dorsi is the big superficial muscle of the mid-section. Despite so, the Lats is commonly not perceived as a core muscle.
Deeper in is the ERECTOR SPINAE (aka Sacrospinalis, Extensor Spinae) muscle group that consist of muscles and tendons that run along the spine on its left and right.
It extends throughout the lumbar, thoracic and cervical regions.
Its major action is to extend the spine (e.g stand up straight from forward bent position).
To keep things simple, we won’t be naming each of the muscles that make up the ERECTOR SPINAE.
Latissimus Dorsi (Right) – Posterior
Erector Spinae Muscle group – Posterior
What once was a muscle few talked about due to its deepness in the body, it is now known as a major stakeholder for lower back pain.
This muscle I am referring to is the Transversus Abdominal (known as TA among many health professionals and fitness enthusiasts).
Although important, the TA is NOT THE ‘core’ muscle(s) but PART of it. The TA wraps around the mid-section like a corset, thus acting as a stabilizer.
Deeper than the TA and inside the pelvic region, we find the Iliopsoas (consisting of Psoas Major and Iliacus) muscles that flexes the hip (i.e. an action that brings the knee and pelvis together).
Iliopsoas are the muscles that extend across from the lumbar section to the upper thigh region.
Psoas Major (Left) – Anterior
Iliacus (Left) – Anterior
Now, let’s return to answering the question. One who has strong muscles that made up the ‘core’ DO NOT necessarily make one immune to lower back pain.
Even if one is referring to the TA only when they talk about the ‘core’, it remains the same. In my opinion, there are five major inter-related factors.
- How balanced the strength of the muscles are relative to its opposing/antagonistic muscles affects your risk of low back pain. For example, if you have strong Rectus Abdominal (spinal flexor), you should also have just as strong spinal extensor.
- Strong TA does increase stability of the mid-section thus reducing the risk of spinal trauma or injury. However, it is one among other factors.
- The positioning of pelvis is important to the posture and the vertebral alignment and that can contribute to low back pain. This is related to the strength, control and coordination of the lower abdominal (spinal flexor) and lumbar spinal extensor. As the lower abdominal coordinates with the gluteal muscles to tilt the pelvis, it is also the reason why having a strong gluteal (the buttocks!) can reduce the stress on the spine and avoid back pain.
- Excess abdominal weight can often compromised the third factor outlined above. This is the reason why weight loss can relieve low back pain in the long term. The third factor can also be compromised when a woman is heavily pregnant.
- Lastly, how you use or rest your body, the position you are in for prolonged period, and the amount and type of physical activity can also affect the above factors. This is the reason why prolonged sitting can result in low back pain.
Please note this article is written with a focus on muscles and there are other factors that can lead to low back pain. This article is primarily referring to non-specific low back pain, which is not due to any specific or underlying disease. The article is written by Dan Chan (PhD, AEP, ESSAM) and it is his perspective as an exercise physiologist.