“The Mighty Psoas”
I am excited to introduce to you my favourite muscle in the body, the psoas; a muscle that is often considered to be the most important muscle in the human body. A healthy psoas is essential to your ability to move well, from getting up out of bed in the morning, to walking and running, and even standing upright. It is the only muscle to connect your spine to your legs making it a vital postural muscle, mover and stabilizer of both the hip and lumbar spine.
Where is it and what does it do?
Your psoas muscles are the deepest muscles in your core. There is a psoas major and a psoas minor muscle. Psoas (from the Greek, “psoa” meaning “loin”) is a general term, but typically refers to the psoas major. The psoas minor is often absent in individuals so will not be considered here.
The psoas attaches at the level of the twelfth thoracic (T12) and each of the five lumbar vertebrae (L1-5), and intervening intervertebral discs, travels down through the pelvis, deep to the inguinal ligament, and across the hip joint, before attaching to your femur (at a bony prominence called the lesser trochanter).
The psoas unites with another muscle in the lateral pelvis. It joins with the iliacus to form the iliopsoas muscle just before the inguinal ligament, before sharing a common attachment on the femur.
Role of psoas in hip and lumbar motion:
As a muscle that passes across two joints, it has a key role in the motion and stability of the both the hip and lumbar spine. The psoas, together with the iliacus, is the most powerful hip flexor in the body, allowing you to bring your hips and legs towards your chest, so you can move your legs forward when you walk or run. It also assists in lateral rotation of the thigh.
Acting from its insertion in the lower back the psoas flexes your trunk forwards on the hip, as in sitting up from the supine position, or when bending over to pick something up off the floor. The psoas also assists the other spinal muscles in ipsilateral side bending and contralateral rotational movements of the spine, although this is a minor role. Some firers of the psoas can even extend the lumbar spine.
Psoas as a key postural muscle and stabilizer of the spine and trunk:
Working in harmony with other core muscles, your psoas muscles have an important role in stabilizing the spine and trunk and in maintaining good postural alignment. Located close to the body’s center of gravity, your psoas muscles help to maintain the optimum position of the spine, pelvis and femurs in relation to each other, and center the spine to support healthy spinal curves. They also assist in the transfer of forces from the spine to the lower extremities.
Provides a shelf for the organs and viscera:
The psoas muscles are in close proximity to many of your internal organs, such as the small intestine, colon, kidneys, pancreas, bladder and spleen. They form a shelf to provide support for the organs of the abdominal core. Movement of the psoas stimulates and massages the abdominal organs thereby influencing the functioning of the organs.
Influences blood and nerve supply:
The psoas muscles also influence nerve innervation and blood circulation. They act as a hydraulic pump, contracting and stretching with every step, stimulating and pushing fluids in out and out of cells during movements, thus stimulating the flow of fluids throughout the body.
Link with the breath:
The psoas muscles have a link to the breath through its’ connection with the diaphragm, the main breathing muscle. The psoas connects to the diaphragm via connective tissues or fascia, which come together at a point known as the solar plexus. By linking to diaphragm motion, the psoas muscles also enables a mechanism whereby the psoas massages the organs, nerves and blood vessels.
The Fear reflex:
The psoas is involved in the fight or flight response, such than when we are stressed, the psoas muscles instinctively tighten, curling us up into a ball to protect us from danger. In today’s stressful world, emotional stresses and trauma, fear and anxiety can all influence the health and vitality of the psoas, causing chronic tightening.
The Dysfunctional Psoas
Given the varied roles of the psoas mentioned, it is no surprise that the psoas is a common source of dysfunction, causing problems in both sedentary and athletic populations. As with any muscle, the psoas has the potential to become stronger or weaker, shorter or lengthened, depending on your lifestyle.
The psoas muscle is particularly prone to getting short and tight from the stresses and strains of everyday activities. Sitting is the big one! Most of us spend far too many hours a day sitting, whether it’s sitting at your desk at work, working on the computer, watching TV, playing video games, reading or driving. If you sit for a good portion of the day, chances are your psoas is tight! It can also be caused by much loved activities such as excessive walking, running or cycling, as well as weakness in the abdominal and gluteal muscles, and even chronic stress.
What happens when the psoas muscle becomes short and tight?
A short and tight psoas has postural implications. Resulting muscle imbalances and compensation in other areas of the body can all lead to other problems with the potential for injury.
Some of the consequences of a short and tight psoas muscle include:
- Injury to the psoas muscle itself – stretch, tendonitis, tear or rupture of the psoas
- Postural implications – a short and tight psoas causes:
- The pelvis to tilt anteriorly, which increases the lumbar curve (lordosis)
- The spinal extensor muscles in your lower back, and the rectus femoris (part of the quadriceps at the front of your thigh), to become shorter and tighter
- The opposing gluteal muscles, abdominals and hamstrings, to become weak and overstretched
- Lower back pain – the anterior pelvic tilt increases compression in the lumbar spine facet joints and pressure in the discs, which can lead to lower back pain, degeneration and
increased susceptibility to injury
- Sacroiliac joint pain
- Hip and knee pain, including hip impingement, patella tendonitis, hamstring strains, piriformis syndrome
- Shallow breathing – a tight psoas causes the ribcage to be thrust forwards, encouraging thoracic rather than abdominal breathing
- Menstrual cramps and digestive issues – a short and tight psoas shortens the trunk, which reduces the space available for the organs, influencing the position and therefore function of
- Fatigue – chronic stimulation of the fight or flight response signaling to your body that you’re in danger, leading to exhaustion, adrenal fatigue, and emotional exhaustion.
The psoas is often tight, from too much hip flexion, such as occurs in extended periods of sitting, driving, etc. If you suspect your psoas is tight, there are a few things you can do to help restore balance, and keep your psoas muscles healthy:
- One of the best things you can do is to contact a professional for a full assessment to see if it needs releasing.
- Avoid sitting for extended periods. If sitting for work, or other reasons, be aware of good posture and have a chair that provides good support for your lower back. Try and get up
once every hour and stretch in all directions.
- Sit less and move more; go for a walk, take a yoga class or do pilates.
- If doing hip flexor heavy exercise, such as cycling or running, or if you do lots of sit-ups, try and alternate with some exercises that involve some hip extension for balance.
- Stretch and strengthen the psoas as part of a balanced exercise routine
- Release stress.
Gibbons, J. (2014). The Vital Gluteals: Connecting the Gait Cycle to Pain and Dysfunction, Lotus Publishing, Chichester.
Koch, L. (1997). The Psoas Book, 2nd ed, Guinea Pig Publications, Felton, C.A.
Moore, K. L. & Dalley, A. F. (2006), Clinically Oriented Anatomy, 5th ed., Lippincott Williams & Wilkins, Baltimore.
Rolf, I. P. (1989). Rolfing: Reestablishing the Natural Alignment and Structural Integration of the Human Body for Vitality and Well-Being, Healing Arts Press, Rochester, Vermont.
Staugaard-Jones, J. A. (2012). The Vital Psoas Muscle; Connecting Physical, Emotional, and Spiritual Well-Being, Lotus Publishing, England