Filet Mignon AKA the Psoas

Several people have commented on the photo of the psoas muscle in our last newsletter. It is quite an impressive muscle, the thickest muscle in our bodies and the only muscle that connects our thighs to our trunk. It originates from the front of the lumbar and last thoracic vertebra (transverse process of T12-L5 and the lateral aspect of the disks) and attaches to the inside of the thigh (lesser tubercle of the femur). The psoas is joined at the hip, by the iliacus, which travels from hip to thigh. Together, the psoas and iliacus make up the iliopsoas, the body’s most powerful hip flexor. It is no wonder why connoisseurs call the cow’s psoas “filet mignon.”      

For the expert athlete and the regular exerciser it is very important to keep this powerful muscle in tune. Every time you bend your knee or take a step the psoas contracts and when your leg swigs back it lengthens. During a slow 30 min jog, averaging 150 strides per minute, the left and right psoas each contract and lengthen more than 4,000 times. That’s a lot of activity on this band of muscle. When a ballet dancer lifts their leg in a turned out position, the psoas is working hard to flex the hip and turn out the leg while holding the full weight of the leg against gravity. When the muscles of the hip and core are in balance, not only does the psoas flex and turn out the femur at one end, the psoas also helps stabilize your spine at the other end. When the psoas is stronger then the other core muscles, the spine can be pulled forward into hyperextension or excessive arching putting additional pressure on the disks as well as tightening the low back muscles. Moreover in a lordotic “sway back” posture the over stretched abdominals and inhibited gluteal muscles will not work efficiently, thus decreasing performance.

Sitting for long hours can be just as destructive for the psoas. The seated posture puts the psoas in an inactive shortened position; over time this can cause a short and weak psoas. A shortened weak psoas alters your posture by pulling the spine towards the legs tipping the pelvis forward thus causing lumbar lordosis, which is arching of the lower back. In addition, the upper portion of the psoas can pull the thoracic spine down leading to a rounded upper back; creating a hump in the upper back and an arch in the lower back. A short weak psoas on an osteoporotic spine can lead to terrible posture, increase the risk for compression fractures and falls and decreased height.

As you can see a weak or overworked psoas can wreck havoc on your spine. If one side is tight it can rotate the vertebra towards the tight side leading to scoliosis. Not only can it pull the spine towards the leg but the leg towards the spine. In this scenario the psoas turns the foot out and pulls towards the spine making the turned out leg appear shorter. The psoas and the back extensors will over work and continue to tighten. Hence, a tight psoas can lead to poor posture, altered body mechanics, and increased pressure on lumbar disks, increased muscle tension and pain in the low back.

One way to test if your psoas is tight is to lie on your back with your legs straight, hug one knee to your chest.

If the thigh on the floor lifts up, then you have a tight psoas.

Bellow is a stretch that can be done to elongate the psoas:

Psoas stretch – keep abdominals in to prevent arching or twisting the spine. Keep back knee slightly bent to prevent compressing the low back. A stretch should be felt in front of the thigh.

  

And two exercises to strengthen the abdominals and glutes with an elongated psoas:

Plank – elbows under shoulders, abdominals tight, pelvis neutral raise one leg elongating the front of the hip, activate the gluteal and hamstring muscles with out changing the pelvis.

Single leg bridge – come up in a bridge, then lift one leg with out changing the pelvis. In this picture the right psoas is elongating and the hip extensor muscles active, the left psoas is actively flexing the hip and stabilizing the spine simultaneously.

 

A balanced routine for the psoas is to combine your cardiovascular exercise with core strength and stretching or cross train with Gyrotonic® exercise or Pilates. Let your instructor know you are concerned about having a tight psoas. If your back is hurting see a Physical therapist and they will perform stability and flexibility tests to measure the length and strength of you psoas and how it is affecting your posture and movement patterns.