Muscle Review: The Psoas!
Do you have a favorite muscle?! I do! It’s the psoas – pronounced ‘so-az’.
So, your “psoas” is actually two muscles, the psoas major and the psoas minor. These two
muscles grouped together are your deepest core muscles as they are found beneath your
abdominal muscles. The psoas originates from the lumbar vertebrae (L1-L5) and runs along side
the spine and then joins the iliacus muscle (which lines your pelvic bowl). The two form the
commonly, and incorrectly, termed “iliopsoas”, which attaches at the lesser trochanter of the
femur (think upper, upper, inner thigh bone). It is the only muscle that connects your spine to
Contrary to popular belief, the psoas muscle is not solely a hip flexor. Yes, it is involved
in drawing the torso and leg closer together, however it serves many more core stabilizing
functions. When the psoas is healthy and pliable, it allows the leg to swing freely as you walk or run. The psoas also counters the muscles surrounding and supporting the lumbar spine in your lower back. In this way it keeps you upright and assists in healthy posture. As you twist, turn or lean your psoas supports and stabilizes your side-to-side motions. It plays major roles in flexibility and range of motion, core strength, organ and nerve function, and breathing!
It should be noted that the psoas works by eccentric contraction; it lengthens (rather than
shortens) along the front spine upon contraction. In many individuals the psoas is restricted or tight. Overworked or weaken muscles may result in poor posture and alignment that requires the psoas to be continuously worked and unable to relax. Misalignment and tension restricts proper movement and function of the psoas, contributing to compressed organs, nerves and circulation for blood and lymph. Constant strain at the psoas can be a major factor in lower back pain, sciatica, scoliosis, hip/knee/ankle tension and misalignment, increased menstrual pain, and digestive and bladder problems.
Pilates instructor and psoas enthusiast Liz Koch (she has been singing praises of and
teaching about the psoas for over 30 years) highlights why it is so essential to maintain a healthy psoas:
It tells a story about an essential midline called the primitive streak from which
everything emerges. Within this paradigm the psoas grows out of the human midline and is a
messenger of the central nervous system; integral to primary reflexes, neurological
proprioception, and personal integrity.
- Pilates Digest, September 8, 2009
So, now that you know all about the psoas, I know you’ll want to keep it healthy. Check
out the following websites for information and some insight as how to keep your psoas in
How to Stretch and Strengthen the Psoas
The Runners Guide to the Psoas
Psoas and Your Back & Psoas Stretches
3 Myths About the Psoas
The Psoas: The Muscle of the Soul