The psoas major muscle (pronounced “so-as”) is often referred to as the deepest core, or as yoga therapist and film-maker Danielle Olson states, the “muscle of the soul.” This core-stabilizing muscle located near the hip bone affects mobility, structural balance, joint function, flexibility, and much more. In addition to its function to help keep the body upright and moving, the psoas is believed to allow you to connect with the present moment especially when it is stretched out and tension is released from the body.