Transversus Abdominis - The Golden Muscle!
In this blog, we will discuss why your transversus abdominis (TA) is such an important muscle when it comes to preventing and/or treating tummy muscle separation, back and pelvic dysfunction.
To explain this, we firstly need to refresh you on your abdominal wall anatomy.
Your abdominal wall is made out of three distinctive layers.
Your first layer is your rectus abdominis (also known as your ‘six-pack’ muscle) which is classified as your “outer core”. Your rectus is a powerful muscle that flexes your trunk, such as when you crunch to get out of bed.
Your second abdominal layer, your obliques, is also a part of your outer core, and is responsible for trunk rotation, such as when you turn to look over your shoulder.
Last, but definitely not least, is your TA muscle, which makes up the third and deepest layer of your abdominal wall and is referred to as your “deep or inner core”. Unlike your outer core, your TA is not a “powerful” muscle, but has a larger proportion of slow twitch muscle fibres, allowing it to gently contract over longer periods of time - often without your conscious thought. In other words, your TA silently hums away all day long, providing subtle and deep support to your back and pelvis. It is also responsible for postural endurance. Allowing you to sit, stand or walk for longer periods of time without getting achy in your back and hips. Your TA also contributes to the contour of your tummy.
From research we know that your TA should automatically turn on (just a little bit) prior to exertion. In other words, your TA should turn on a few milliseconds before you cough, sneeze, lift, or stand up from a chair. This automatic function can sometimes go out the window if you experience back, pelvic or abdominal pain/dysfunction, or if you’re pregnant or have recently had a baby.
Retraining your TA is therefore an essential part of your back/pelvic/abdominal or pre/postnatal rehabilitation, as it is vital to regain the deep and subtle support it provides to your spine and pelvis.
A well-functioning TA helps to prevent and/or treat abdominal doming (also referred to as coning or tenting), which commonly occurs in the later stages of pregnancy and in the early postnatal period. Eradicating abdominal doming reduces the risk of excessive or prolonged tummy muscle separation.
To explain this further we again need to refer back to your abdominal anatomy.
So, let’s go back to discussing those three distinctive abdominal layers which join together at the front via a central ligament/connective tissue called your linea alba (easy to remember by thinking about actress Jessica Alba).
Now it’s important to know that your TA and linea alba have a very special relationship! Due to the transverse (i.e. horizontal) orientation of your TA muscles fibres (hence the name TRANVERSE abdominis), when your TA contracts it pulls your linea alba taut. Kind of like pulling two ends of a rope taut, or tightening a guitar string. By pulling your linea alba taut it prepares your abdominal wall for loading, allowing your outer core to transmit/generate force, and prevents the linea alba from herniating out front (abdominal doming).
An example of this is when you cough. Just prior to coughing your TA should automatically turn on pulling your linea alba taut. To execute a strong cough your six pack and obliques need to turn on quickly and strongly. If your linea alba is pulled taut your outer core has a firm anchor to contract from, allowing it to generate enough force to achieve a nice big cough. Because your linea alba has been pulled taut, when your outer core contracts increasing intra-abdominal pressure, all this pressure is forced upwards toward the diaphragm producing a ‘cough’. However, if the TA does not ‘pre-activate’ and the linea alba is lax, rather than all the intra-abdominal pressure going upwards, some of it will instead push out through the centre into the ‘lax’ linea alba, causing it to dome outwards. An example of abdominal doming can be seen in the diagram below:
As previously mentioned, abdominal doming commonly occurs in the later stages of pregnancy and in the early postnatal period.
Avoiding/minimising abdominal doming pre and postnatally is extremely important to protect your linea alba. Repeated doming can result in over stretching of the linea alba making this connective tissue thin and flimsy (similar to an overstretched rubber band that has lost its ability to recoil).
If the linea alba loses its ‘recoil ability’ this can result in prolonged or excessive tummy muscle separation postnatally.
Rehabilitating your TA may not only help to prevent abdominal doming in pregnancy but can also help to tighten and thicken up your linea alba postnatally, helping it regain its elastic tensile properties (similar to a really thick stiff rubber band that is resistant to stretch). This is why your transverse abdominis is the GOLDEN MUSCLE when it comes to preventing and/or treating tummy muscle separation!
If you experience back/pelvic girdle/hip pain, pelvic floor dysfunction, abdominal doming or have tummy muscle separation The Pelvic Studio can help. A physiotherapy assessment involves a thorough abdominal examination including a real-time ultrasound assessment of your deep core function.
