If you guessed C, you're correct. Buried deep within the core of your body, the psoas (pronounced "so-az") affects every facet of your life, from your physical well-being to who you feel yourself to be and how you relate to the world. A bridge linking the trunk to the legs, the psoas is critical for balanced alignment, proper joint rotation, and full muscular range of motion. In yoga, the psoas plays an important role in every asana. In backbends, a released psoas allows the front of the thighs to lengthen and the leg to move independently from the pelvis. In standing poses and forward bends, the thighs can't fully rotate outward unless the psoas releases. All yoga poses are enhanced by a released rather than shortened psoas. (When you reverse your orientation to gravity in inversions, however, the psoas must be toned as well as released to maintain proper spinal stability.)
Whether you suffer from a sore back or anxiety, from knee strain or exhaustion, there's a good chance that a constricted psoas muscle might be contributing to your woes. Getting in touch with this deeply buried muscle can be humbling at first. You may discover that you've been doing many poses by contracting your core, instead of relying on your skeleton for support and allowing your more peripheral muscles to organize around a toned but flowing and spacious center. But if you persevere, psoas work can add new insight, openness, and stability to your practice. Though your psoas may not be as easy to sense as your biceps or hamstrings, improving your awareness of this crucial muscle can greatly enhance your physical and emotional health.
Along with improving your structural stability, developing awareness of your psoas can bring to light fears long locked in the body as unconscious physical tension. Intimately involved in the fight or flight response, the psoas can curl you into a protective fetal ball or flex you to prepare the powerful back and leg muscles to spring into action. Because the psoas is so intimately involved in such basic physical and emotional reactions, a chronically tightened psoas continually signals your body that you're in danger, eventually exhausting the adrenal glands and depleting the immune system. As you learn to approach the world without this chronic tension, psoas awareness can open the door to a more sensitive attunement to your body's inner signals about safety and danger, and to a greater sense of inner peace.
Meet Your Psoas
To locate this powerful muscle, imagine peeling your body like an onion. The first layer is the skin; next come the abdominal muscles in front and the massive muscles of the sides and back. One layer deeper lie the intestines and another layer of back muscles. Continue peeling each layer until just before you reach your skeletal core: There in the center of your inner universe rest the psoas muscles. One on each side of the spine, each working independently yet harmoniously, the psoas attaches to the side and toward the front of the 12th thoracic vertebra and each of the lumbar vertebra. Moving through the pelvis without attaching to bone, the psoas inserts along with the iliacus muscle in a common tendon at the top of the femur.
A healthily functioning psoas provides a sensitive suspension bridge between the trunk and the legs. Ideally, the psoas guides the transfer of weight from the trunk into the legs and also acts as a grounding wire guiding the flow of subtle energies. Working properly, the psoas functions like the rigging of a circus tent, stabilizing your spine just as guy wires help stabilize the main pole of the big top.
In addition, the psoas provides a diagonal support through the trunk, forming a shelf for the vital organs of the abdominal core. In walking, a healthy psoas moves freely and joins with a released diaphragm to continuously massage the spine as well as the organs, blood vessels, and nerves of the trunk. Working as a hydraulic pump, a freely moving psoas stimulates the flow of fluids throughout the body. And a released, flowing psoas, combined with a stable, weight-bearing pelvis, contributes to the sensations of feeling grounded and centered.
Think of your pelvis as the foundation of a balanced skeletal structure. For your pelvis to provide this stable base, it must function as part of the trunk rather than as part of the legs. Many people mistakenly think of their legs as starting at the waist, perhaps because so many major leg muscles attach to the pelvis. But skeletally and structurally, your legs start at your hip sockets. If your pelvis tilts forward or back or side to side every time you move your legs, the bones can't bear and transfer weight properly. Your psoas will then be called upon to help protect the spine by stabilizing your skeleton. Since the psoas can contract and release independently at any of its joint attachments, it can compensate for structural imbalances in many ways. But if you constantly contract the psoas to correct for skeletal instability, the muscle eventually begins to shorten and lose flexibility.
Shortening the psoas leads to a host of unfortunate conditions. Inevitably, other muscle groups become involved in compensating for the loss of structural integrity. The pelvic bowl tips forward, shrinking the distance between the pelvic crests and the legs, and the femurs are compressed into the hip sockets. To compensate for this constriction, the thigh muscles become overdeveloped. Since full rotation of the thighbones can no longer occur in the hip joints, much of the rotational torque is transferred to the knees and the lumbar spine—a recipe for knee and lower back injuries. In your yoga practice, if you feel strain in your knees or lower back in seated and standing poses, your body may be telling you that you need to lengthen your psoas.
In addition to structural problems, shortening the psoas limits space in the pelvis and abdomen, constricting the organs, putting pressure on nerves, interfering with the movement of fluids, and impairing diaphragmatic breathing. Finally, by limiting your options for movement and by constricting your center, a shortened psoas decreases both your vitality and your connection to the sensations at your skeleto-muscular and emotional core.
Losing touch with your core can happen in myriad ways. You may be born with structural imbalances that eventually lead you to engage the psoas for support. All sorts of physical traumas can compromise the optimal, healthy functioning of your psoas: injuries to the pelvis or spine, surgery, broken bones and joint injuries in your feet and legs, even a torn ligament from overexuberant stretching in yoga. No matter what their source, muscular imbalances that compensate for injuries, overdeveloped muscles, and chronic muscular tension all add to structural instability that affects the psoas.
In addition, our living environment often does not support the proper use of the psoas. From car seats to constrictive clothing, from chairs to shoes that distort posture, many features of modern life curtail our natural movement patterns. In fact, a chronically tightened psoas may date back to your first steps. Baby shoes that constrict the foot, impair the movement of bones, or limit ankle mobility can alter a child's skeletal balance and stifle psoas vitality. Other child-rearing paraphernalia can add to the problem. Rigid plastic baby carriers limit movement, eliminating the natural protection and give-and-take of a mother's body, and playpens restrict the crawling essential for neuromuscular and skeletal maturation. Walkers give infants a false sense of stability, encouraging them to stand and walk before the bones are fully formed and ready to bear weight. Rushing development in this way teaches children to rely on their psoas muscles, rather than their skeletons, for support.
Either emotional trauma or an ongoing lack of emotional support can also lead to a chronically contracted psoas, and thus to a loss of core awareness. If your fight/flight syndrome is triggered into constant arousal, eventually you lose contact with your inner world. One psoas workshop participant, for example, recalled her mother repeatedly admonishing her, "Look where you're going, young lady." Constantly receiving the message that her body couldn't be trusted led her into chronic anxiety. She realized she literally watched every step she took, forcing her skeleton to sag under the weight of a drooping head.
As an adult, learning to consciously release your psoas can rekindle vital energies by re-establishing your connection to your body's internal signals—your instinctual somatic wisdom. Releasing your psoas encourages this process by allowing you to trust your skeletal stability instead of holding yourself up by muscular effort. Sensing your bones supporting weight translates into a physical and emotional feeling of "standing on your own two feet." With a properly functioning psoas, the bones bear weight, the muscles move the bones, and the joints connect the subtle energies of the body. Energy flows through the joints, offering a sense of continuity, like the string flowing through a pearl necklace that transforms it into something more than the sum of its parts. The psoas, by conducting energy, grounds us to the earth, just as a grounding wire prevents shocks and eliminates static on a radio. Freed and grounded, the spine can awaken.
Once you've learned to sense and release your psoas, you can apply these lessons to your yoga practice and everyday life. Keeping your psoas released during yoga practice liberates attention previously directed toward your contracted core, allowing you to sense more clearly the delicate balance of action between other muscle groups. And freeing your center creates a sense of relaxation and calm that can infuse all your activities. In his poem "Burnt Norton," T.S. Eliot wrote a phrase that perfectly captures the inner stability and peacefulness that accompanies a properly functioning psoas: "the still point of the turning world."
Author of The Psoas Book, a guide to the iliopsoas muscle and its effect on the body, mind, and emotions (Guinea Pig Publications; P.O. Box 1226, Felton, CA 95018; www.guineapigpub.com), Liz Koch has taught psoas workshops for over 20 years. She lives in Felton, California, with her husband Jeff Oberdofer and their three children.