For many of us, psoas (pronounced “so-as”) a completely foreign term to our ears or eyes. For some of us, we know this word better as “hip-flexor.” Without getting too complicated, the psoas is a muscle which helps to bring the leg toward the torso (hip flexion) or vice versa. It also plays a roll in some side bending of the spine (lateral flexion). To be a little more complicated, the psoas is composed of the psoas major and minor (fun fact: the psoas minor only exists in a certain percentage of people). Major attaches from the lower lumbar (low back) spine through the pelvis, to the inner portion of the leg bones. It is the deepest muscle in the core and the only muscle that attaches the spine or torso to the legs directly.
Functionally, the psoas plays a major role in the position of the body in seated, walking, and even in standing.