The transversus abdominus (TA) muscle is the deepest layer of the abdominal wall. It wraps around you similar to a brace or corset and attaches at the back to your spine. When it contracts it “stiffens” and supports the spine and is therefore vital to spinal stability and control. Core stability refers to the sub-conscious use of TA and other muscles, such as the gluteal (bottom) muscles, to provide an effective stable base for activity and exercise and to support the lower back.
Physiotherapy research has clearly demonstrated that:
1) The TA muscle is inhibited (weak and dysfunctional) in people who have low back pain (LBP).
2) It does not spontaneously strengthen after the back pain goes.
3) People who do not retrain this muscle after an episode of LBP are far more likely to have a recurrence in the first year.
4) People with poor core stability (weak TA) are more prone to LBP.
Initially, it is vital to learn to contract TA consciously in isolation. If the muscle is weak, it will notactivate automatically on the fitball or with Pilates. These exercises are used only once you can isolate the TA and perform multiple contractions easily. A TA contraction is easiest to learn initially in a non-weight bearing position.
To start, lie on your back with your legs bent up and feet flat on the ground. Find the bony prominence at the upper front part of the pelvis on each side (usually 10cm out to the side from your navel). Slide your fingers or thumbs deep into the abdomen and cough. You should feel a pushing out against your fingers by muscles called the oblique muscles – these are the wrong muscles to contract, so if you feel a pushing out feeling then you are contracting too hard.
Next, focus on you breathing. With each in breath, make sure the air is going to the bottom part of the lungs/ribs and feel your upper stomach expand. It should then deflate with each out breath. This is called diaphragmatic breathing.
Now, breath in, start to breath out through your mouth and at the same time slowly and gently draw your naval in toward your spine. Pretend someone has a piece of string attached to the inside of your belly button and that they are pulling it inwards about half way. You should feel a subtle tightening against your fingers (which should still be feeling for the contraction) but no pushing out.
The tricky bit is to then hold the contraction while you continue to breath for 10 seconds. Most people find that they can do the contraction but lose it as soon as they start breathing. This perception of contraction with breathing should improve within a few days. Do not hold your breath as you will use the wrong muscles. The aim is to be able to contract the TA, continue breathing, hold for 10 seconds and repeat this 10 times in a row easily. Practice it 3-10 times per day for rapid improvement.
There is new research to suggest that the pelvic floor muscles are just as important as the TA in the rehabilitation from LBP. If you are aware of your pelvic floor (such as post-childbirth) – try and contract these muscles prior to contracting TA and you will feel TA activate also. The two muscles work together to support the spine and pelvis. Activating the pelvic floor prior to TA can be a useful way of getting TA working.
Once you have better control and endurance of your TA you trainer will you show you how to progress the basic exercise by adding arm movements or leg lifts. You then need to practice activating the muscle in sitting and standing prior to starting stability work on the fit ball or in Pilates.
You are not alone. Many people struggle with “finding” the muscle initially especially if they have had a long history of back pain. Your local physiotherapist has many strategies to use to facilitate activation of TA, so pay them a visit. Remember, if you have LBP and you have not learned how to activate TA, more advanced exercises in the gym may well just re-enforce your usual movement patterns and contribute to your symptoms.