Whenever the psoas muscle shortens, it pulls the spine into a condition known as hyperlordosis, which is the exaggerated curvature of the lumbar spine. Naturally, this puts a lot of strain on your spinal muscles, most notably the erector spinae. Muscles are not the only affected tissues, however, as psoas contraction strains vertebral joints as well. This is ultimately what causes the painful symptoms associated with the condition.

A contracted psoas muscle will also cause biomechanical imbalance of hip and spine which may cause compression of the spinal discs and joints. This is because the muscle pulls and twists the vertebrae, leading to compression. Spinal compression causes pain and will eventually wear down the spinal structures as time goes by. This leads to structural damage, degenerative disc diseases, and sometimes herniation of the disc also.

How do we get it?

Chronic psoas shortening or weakness can be caused by exercise programmes continually and repetitively using hip flexion. Sedentary lifestyle and sleeping in the fetal position can also result in dysfunction of the psoas muscle.

Psoas compensates for the difference in strength of the abdominal muscles and posterior spinal muscles, so if imbalance is found here psoas dysfunction may occur as a result in an attempt to stabilize the lumbar spine.

Test for Hip tightness : Thomas Test 

Lie faceup on the very edge of your bed or a sturdy table, so your legs hang off. Bring both knees towards your chest so your back lies flat against the bed. While holding one knee close to your chest, slowly straighten your other leg and let it hang off the edge.

You passed the test if your back and the back of your lowered thigh is flat against the bed, and your hanging knee is bent at a 90-degree angle off the surface.

A passed Thomas Test, where the back and thigh are flat against the table and the knee hangs off at a 90-degree angle.

A failed Thomas Test. The leg is extended due to a tight rectus femoris, and the thigh is off the table due to a tight iliopsoas.

Hip flexors Stretches 

Stretch has to be felt on the upper front  thigh which is stretched backwards