The Psoas (which has a silent P and therefore we say Soas) consist of the Iliopsoas muscle (which is the Psoas Major and the Iliacus) and the Psoas Minor. We aren’t going to focus on the latter but instead give the attention to the bigger and more significant of the muscles which both join the lower half of the body (since they attach distally at the top of the femur (upper leg bone)) to the upper half of the body (since they attach proximally to the vertebrae of the spine from T12 to L4/5. Their primary function is FLEXION, hence the popular term “hip flexor”. They are quite amazing in that they cross 9 joints and are responsible for a lot of postural issues we encounter in everyday life as well as being responsible stabilisation of the spine.
Although Psoas Major is grouped with Illiacus as part of the Hip Flexor group, it has a slightly different function so it is a little simplistic to say call them all hip flexors. The hip flexion function of Psoas is secondary to its lumbar-sacral stability function. Rectus Femoris and Illiacus have more of a role in hip flexion.
When a person presents with a marked Lordotic curve in the lower back, the fault lies with the Psoas where the lumbar spine is being pulled down and forwards by the attachment at L2- 5. This forces the anterior pelvic tilt and necessary tightness in the front of the thigh. Equally, if a person is stooping (from poor posture and probably a lot of sitting) the Psoas is the culprit again since a tight attachment higher up the spine at T2 – L2 will be pulling the thoracic spine down and forward. The tightness and weakness of these muscles has an affect on balance, movement and even the capacity to breath deeply. I have noticed that if the Lordotic curve is high, it is more likely that Psoas contraction is the culprit.
Basically speaking, the Psoas is in charge of helping you bend your knee. It is an easily abused muscle if you sit a lot since it will be passively shortened in this position at the front of the hip. In sitting, Psoas is about 3 inches shorter than it is when we are standing in a good posture. Side sleeping can also contribute because the knees are drawn up during the night and the Psoas necessarily in a shortened position. Our modern lifestyle encourages far less movement than our ansecestor and the result of this is a Psoas adaptation that presents as an anterior tilted pelvis with rib flare. Psoas is also said to be very responsive to stress and is prominent in both Red and Green Light Postural modes. Think of the sway back in the hyper alert state of GLC and the knee drawn up protectiveness of a Red Light Posture faced with fear and depressive tendencies.
Having your computer on the desk and maybe slightly leaning forward towards it encourage the head the come forward (quite weighty) which further forces the hip flexors to contract (because the weight is forward) and the low back therefore also becomes contracted (Lordosis). Following this pattern in sitting, when we get up to stand, we think we are straight but there is residual hip flexion – ie we haven’t stood fully upright and there is still a crease at the point where the legs join the trunk. The muscle has been tight for so long, it can’t lengthen fully to allow us to stand upright. If we do manage to fully extend at the crease, this forces a hyperextension of the lower back – a co-contraction with the hip flexors. Another common cause of a tight Psoas is the body weight being slightly too far forward and the weight in the balls of the foot. This posture causes the muscle to shorten in the same way.
In Somatic Yoga the Psoas is seen as mostly too tight or too weak. Our aim is to release the front of the body first to allow the Glutes to work correctly. If we visit the Physiotherapist, Chiropractor or Osteopath with low back pain, they will often say that the Glutes are weak. However in Somatics it is believed that they can be enabled if the front of the hip flexor is adequately released – there is no need to train the Glutes on their own… this will happen naturally if the front is long. We train the muscle through Sensory Awareness to lengthen fully and smoothly contract when required and of course avoid sitting for long periods as much as possible!
The Psoas crosses so many joints that it has influence on such a broad range of the body. It is a major contributor in low back pain as well as being responsible for pelvic symmetry and how we hold our rib cage. It can be the cause of a hip snap if you are doing leg lowering (a clunking feeling) or a pinching feeling in the front of the hip when you are doing exercises that challenge the Psoas or even when you bring knees to chest;
If Psoas is tight, the attachment point at T12 (bottom of ribs) will be pulled forward which we call a rib thrust or rib flare where the lower ribs are further forward and lifted than they should be. Will focus on this rib flare in class this week. What that does in the high back body (thorax-lumbar region) is to pull the low back into an exaggerated upper lumbar curve (Lordosis) or sway back. So the person is in a permanent back bend position very indicative of Green Light Reflex. This posture is seen to be a problem of pelvic positioning however a closer look will reveal a much higher curve in the back and sometimes the pelvis is actually posteriorly tilted and the limbo-sacral curve becomes lessened. If one side of the Psoas is tighter than the other, there will be Scoliosis in the spine and the pelvis may be twisted (set further back on one side) or lifted on one side.
In my observations this postural response to the Psoas is reflected in the style of thinking of the person in which there is hyper-alertness, intelligent, quick over thinking and an addiction to busyness (which I am calling Green Light Consciousness) that is so prevelant in our modern day culture. If you ask this person to stand upright, they stand to attention like a sergeant major and out pop the ribs! In this position the Psoas is shortened and tight.
We are not aiming to stretch Psoas Major – we are releasing it. We are helping the body to unlearn it’s postural response to a short and tight Psoas. We aim to note asymmetric tension patterns in the pelvis and the position of the rib cage in various poses. We also aim to wake up a sleepy back body, in particular, gluteal amnesia! We are aiming to increase the range of motion in hip extension which has become limited by a tight hip flexor.
We focus on the position of the pelvis in order to obtain a neutral positioning which in turn allows the pelvic floor muscles to gain their optimal length and position. It also optimises the functioning of the diaphragm muscle and assists in a better deep breathing action. This makes us feel more stable internally (which some have called “core stability”).
The poses to avoid if the Psoas is tight are Boat Pose and leg lifts which overly activate an already tight muscle
More details about Psoas Dysfunction:
Yoga Teacher Resource Podcast
“The Psoas Major in Yoga and in life”