co-authored by Emily Bolling This article first appeared The Frontiersman Currently in my yoga classes we are exploring different muscles each week, and I became fascinated by all that was written about the Psoas (so-az) muscle.   There is literally a whole book, "The Psoas Book" by Liz Koch on the subject. In Koch's book she explains that the psoas resides where our gut feelings are felt and is our center for personal power and the control of our feelings. Your "gut feeling" is our emotional intelligence, the intuitive part of your body that tells you when something isn't right.   As we grow older many of us tend to ignore and tune out this gut feeling when we should really be focusing and tuning in to what it has to say.   In this article I would like to focus on the amazing psoas muscle, how it is affected by anxiety and the " fear reflex ", and importantly, how to relax the psoas, and ways you can stretch and release it . Location of Psoas The psoas, 16 inches long attaches along the belly side of all the lumbar (low back) vertebrae and the 12 th thoracic vertebrae.   It travels through the pelvis where it integrates with, the iliacus muscle where both attach to the top of the femur. The psoas is the keystone of a balanced, well-organized body that links the ribcage and trunk with the legs, and acts as a shelf for the abdominal organs.   Deep within your gut is a merging point (located at around the 12 th thoracic vertebrae.), of your diaphragm, the solar plexus and two large muscles, the trapezius, coming down from the shoulders, and the Psoas coming up from the top of the thighs. Function of Psoas The psoas is basically a hip flexor, and the main purpose of the psoas is that it lengthens or shortens when we walk and run, and contracts when we bend forward from a standing position. It supports the leg's free swing in walking and plays an important role in transferring weight through the trunk and into the legs and feet. The psoas works in balance with the rectus abdominal muscles to balance the body. It can become shortened by continually sitting in a flexed position, which can cause distortion the whole skeletal structure. When too much emphasis is on the abdominals, "Exercises like sit-ups and push-ups, not only weaken the psoas muscle, causing it to tense and shorten, but also can provokes stress to strained back muscles and diaphragm," Koch says.   Fear Reflex             The psoas plays an important role in the fear reflex of our body and contracts when we feel fearful.   According to Koch, she states that "In doing so, it helps protect the person by bringing the extremities together and creating an enclosure that gives a sense of safety."   Unfortunately when we don't have a healthy outlet for this tension, the psoas doesn't get an opportunity to relax.   It stays in a shortened, ready state of contraction, which distorts our posture and breathing.   How to Relax and release the Psoas In her book Koch recommends using the constructive rest position to help release and lengthen the psoas.   Begin by lying on your back, knees bent at a 45 degree angle, feet hip width apart.   Begin to sense your breathing in the belly and allow your thoughts to quiet.   As you lie there, the lower spine will begin to have weight, and will eventually release and lengthen along the floor all by itself, without you forcing it to happen.   This is a result of the psoas muscle releasing.   Force is neither needed nor helpful! Stretching the Psoas A great way to lengthen the psoas is by doing a lunge type of a stretch, like the type you see runners doing before and after a race, due to the demands on the psoas to continually contract. In Yoga there are numerous extension type stretches, like bridge, back bends and the lunge in classic sun salutations that are all very beneficial.   The key to health and wellbeing is finding balance in your life.  Yoga teaches inner awareness of body, mind and breath, allowing our inner intelligence, our "gut feelings" to guide us.