What’s Underneath… Core Muscles

Hey guys, welcome to my new What’s Underneath series, where each post will take a different muscle group and relate it to some beneficial exercises we can do to strengthen them. This is a new style of posting for me, as I’ve only really posted about food and mental wellbeing so far, and not so much about physical wellbeing, but hey, I might as well make some use out of my Anatomy degree while I’m here! Please do send me your feedback and ways you think I could add to, takeaway from or improve these kinds of posts. Thank you.

I’ll never forget the long but rewarding path of my four year BSc degree!

The Core Muscles

The core, or torso, contains a group of muscles located at the body’s midsection. They work to align the spine, pelvis and ribs, while helping us resist force overall. They are the reason we don’t make jerky movements when we are holding or throwing something heavy, and a stable core gives us the balance we need to not fall over during a steep hill walk.

The core is a flexible boundary which keeps the abdominal organs inside their cavities, protects them and helps them maintain their positions against gravity. The muscles assist in forceful expiration (outward breathing) by pushing the abdominal organs upwards. It is also involved in coughing, vomiting and defecation (1). A strong core gives us good balance, better posture and reduces back pain (3).

What are the main muscles of your core?

The main core muscles we talk about are the vertical rectus abdominis (which we know universally as our ‘abs’), the transverse abdominis, internal oblique and external oblique (at the side of our abdomen) and the erector spinae (a set of muscles in the lower back). (3).

The Transverse Abdominis

This is the deepest of the three flat muscles, found at the sides of the torso. This muscle helps to strengthen the wall of the abdomen and compresses the organs inside their cavities, preventing any organ from herniating (breaking through) the abdominal wall.

The Internal Oblique

This muscle is found above the transverse abdominis, it is slightly thinner and weaker than the external oblique muscle, with its fibres also running in the opposite direction to it. When this muscle on both sides of the body is contracted, it tenses the entire abdomen, while use of this muscle on one side of the body rotates the body to that same side.

The External Oblique

This muscle is the largest and outermost of the flat muscles, which helps to flex the torso and it contributes to rotating the opposite side of the body to the side it contracts on.

The Rectus Abdominis

We often call this vertical muscle running down our abdomen our ‘abs.’ It is actually split down the middle into two by something called the linea alba, and is further intersected by fibrous strips, which gives way to the six bumps visible most in the fittest of individuals.  It functions as a lot more than our six pack, being what stabilises the pelvis during walking and what helps to depress our ribs during breathing (1).

The Erector Spinae Muscles

These are a group of muscles and tendons essentially spanning the length of your back, alongside the spine. This group functions to straighten the back and provides for side-to-side rotation. An injury or strain to this muscle may cause back spasms and pain, which is another reason to keep it strong and healthy! (4)

Yes, there does seem to be a lot going on in that group, so how hard is it to get each muscle working out? In fact, the best core exercises we can do to define these muscles and make them look better and more prominent, tend to work most muscles in the core group at once, which leads to overall balanced core strength, which improves core performance and helps us avoid injury to that area.

My favourite core muscle workouts:

The Side Plank

View exercise instructions here.


Image taken from self.com & you can view the exercise instructions here.

The Modified Plank

View exercise instructions here.

High Boat to Low Boat

Image taken from self.com & you can view the exercise instructions here.

Abdominal Crunches

View exercise instructions here.


  1. TeachMeAnatomy. (2019). The Anterolateral Abdominal Wall. [online] Available at: https://teachmeanatomy.info/abdomen/muscles/abdominal-wall/ [Accessed 11 May 2019].
  2. Mayo Clinic. (2019). Slide show: Exercises to improve your core strength. [online] Available at: https://www.mayoclinic.org/healthy-lifestyle/fitness/multimedia/core-strength/sls-20076575?s=5 [Accessed 11 May 2019].
  3. Amy Marturana, C. (2019). 20 Core Exercises Top Trainers Swear By. [online] SELF. Available at: https://www.self.com/gallery/core-exercises-top-trainers-swear-by [Accessed 11 May 2019].
  4. Spine-health. (2019). Erector Spinae. [online] Available at: https://www.spine-health.com/glossary/erector-spinae [Accessed 11 May 2019].

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