The Psoas: more than just a muscle?

Updated: Oct 12, 2018

the psoas muscle

The Psoas is my new favourite muscle! Yes...I have a favourite. Have you been in a Yoga class and ended up in tears, or seen others do so? Believe it or not, that was most probably the Psoas being released. It is not only incredibly influential to your posture but also your emotional well-being.

The psoas is around 40cm long and is the only muscle to connect the trunk to the legs giving it massive importance to our posture. It starts at the twelfth thoracic vertabrae (T 12) and also attaches to each of the vertabrae in your lower back (L 1-5). It then passes itself through the pelvis finally attaching itself to the femur (upper leg bone) to help create flexion in the hip (think of bringing your knee upwards; that is hip flexion). We have 2 of these with one each side of the spine attaching to each leg.

Now what makes the muscle even more interesting is everything it is near and that it comes into contact with; the lumbar nerve complex; organs such as the kidneys, pancreas, bladder, liver, intestines and spleen; the largest artery the aorta; and it meets the diaphragm and a point some may recognise as being called the solar plexus.

This means the movement and well-being of this muscle can affect many organs, affect body circulation, as well as all that is associated with the solar plexus; gut feelings, breath, digestion, metabolism, emotions and the universality of life. Pyschoenergetic science is being increasingly researched as an 'expansion of traditional science to include human consciousness and human intention as capable of significantly affecting both the properties of materials (non-living and living)' [1].

Constructive Rest Position

Also known as semi-supine, you may recognise this position as one of the regularly used starting positions in Pilates exercises. It was actually advocated before this by Mabel Todd, with the term CRP being introduced by Lulu Sweigardy (a student and colleague of Todd's) in the late 1920s. It is also widely used in the Alexander Technique.

Try and spend 10 minutes a day in this position. Focus the mind on your breathing as your feel yourself melting into the ground throughout the body. Really think about the femur (leg) bones sinking into your pelvis and imagine your psoas muscle relaxing more and more. This is great preparation for the muscle as well as a good way to start improving your posture.


So that the psoas doesn't rest heavily against all these important organs, nerves and arteries it crosses it is important for it to be kept long and supple. These stretches are a great way to achieve this.

This one can be performed with or without a foam roller. If your psoas is particularly tight, or you have lower back issues, I would recommend just lying on your back without the roller.


Pilates encompasses many exercises that use the psoas muscle. For example, the roll up is often considered an abdominal exercise, but the psoas is bringing the trunk towards the legs in around 60% of the motion.

Single leg slides are one of the best ways to isolate the psoas. The abdominals work to keep the pelvis stable whilst the psoas is used to create the movement. This is a great exercise even for advanced Pilates students in order to really discover the muscle.

The single leg circle uses the psoas to help the lumbar area (lower back). It also helps to create the movement along with the illiacus muscle; together forming the iliopsoas muscle group. If you listen to all the muscles mentioned in the video you can see what a great exercisse this is.

Nearly all exercises in Pilates either stretch or utilise the psoas in some way. Now you've discovered try and focus your attention on it in your next class and you will hopefully get a lot more from your practise.

This is only a brief introduction into the psoas but if it has sparked an interest and you would like to read further there are two books I highly recommend; 'The Vital Psoas Muscle' by Jo-Ann Staugaard-Jones and 'The Psoas Book' by Liz Koch.

[1] P90, Staugaard-Jones, Jo-Ann, The Vital Psoas Muscle, Chichester, Lotus Publishing, 2012