You may hear the word psoas tossed around in yoga class, but where it is and what does it do? You have a right and left psoas and it is primarily a hip flexor – which means it folds the hip to bring the knee into the chest. Deep in the center of the body, it attaches the entire length of the lumbar spine to the inner thigh. As it crosses the front of the hip, it merges with another muscle called the iliacus. That is why it is sometimes called iliopsoas.
The psoas is important in finding a neutral pelvis. If the psoas is tight, it will pull the lumbar spine forward and increase the lumbar lordosis curve in the lower back. Sitting for too many hours during the day can tighten the psoas. In order to stretch a tight psoas, use poses like high lunge, warrior one and anjaneyasana which lengthen the psoas of the back leg. Conversely, the psoas shortens in poses where the thigh pulls in close to the chest like a step through to lunge from downward dog or boat pose.
Just like everything in yoga, we are looking for balance. I love lengthening the psoas in a neutral position to find this balance. Try it: lie on your back and straighten the left leg along the ground – this is the psoas that will be lengthening. Pull the right leg into the chest. Work on finding length on your left side by pushing your heel away from you. Now imagine that the area just to the left side of your belly button down to your left inner thigh gets longer. Keep reaching your left heel away and take 5 long breaths.