News : Do you have shortening of the iliac psoas?

News :

Do you have shortening of the iliac psoas?

thomas test

There are many types of physical tests and exams to detect different ailments and muscle problems and today we talk about one that has to do with the shortening of the iliac psoas: the Thomas test.

What is the Thomas test?

We call Thomas's test the physical examination test named after its creator, Dr. Hugh Owen Thomas, a British orthopedic surgery professional. The test involves lifting one leg to rule out a hip flexion contracture or a shortening of the psoas.

This test is also known under the name of psoas shortening test or shortening test of the iliac psoas.

Shortening of the iliac psoas

It is a very common pathology among runners and athletes, but also among the sedentary population sector. They are the two sides of the coin: people who do a lot of sport and people who sit a long time.

What is it

The iliopsoas or iliac psoas or psoas muscle is a deep muscle that is located in the upper part of the leg, connecting the lower train with the trunk. He is in charge, next to the gluteus, of hip flexion movement and also of trunk flexion.

When a shortening of the psoas occurs, it means a shorter muscle length and a lower force in the area, which can lead to difficulties in performing certain movements and exercises associated with trunk flexion, such as abdominals.


The main symptom that you will perceive is hyperlordosis and low back pain, which could make you think that you suffer some type of lumbar spine injury when what is really happening is that you have a shortening of psoas.

In addition, due to the shortening, inflammation can occur in the tendon and the resulting pain. When this happens we talk about iliac psoas tendonitis.


Psoas shortening, quadriceps shortening, or suffering both at the same time, are not a particularly serious problem.

Basically, the direct consequence of this type of muscle shortening is that the lumbar spine will be responsible for supporting a greater load and tension than it should and this is due to the lack of movement and flexibility of the hip.

This, in turn, leads to the appearance of pain and the inability to perform certain exercises.

The treatment to improve this mobility and stop suffering the consequences of a shortening of psoas is the realization of stretching and specialized exercises for the work of that area (hip and quadriceps)

How is Thomas's test performed?

Lying on your back on the couch of the physiotherapist, who is the professional in charge of performing the Thomas test, and with the buttock on the edge of the couch, you must lift and flex one of the legs carrying it until it touches the abdomen, with the aim of eliminating lumbar lordosis, and holding it with the hands. The pelvis must be in neutral position, without inclination.

The other leg is hanging and depending on the movement that occurs in it, the result of the test will be one or the other.

  • Thus, if the leg that does not lift stays as it was, with the thigh attached to the stretcher and the knee bent, then you do not suffer No shortening
  • If, on the contrary, the knee is stretched (and the leg is raised) while the thigh is attached to the stretcher, we will be talking about a quadriceps shortening.
  • If in addition to extending the knee, the thigh detaches from the stretcher, it could happen for two reasons: a double shortening of the psoas and quadriceps (when the patient cannot bend the knee and place it more than 90 degrees) or a psoas shortening (the patient can bend the knee at an angle greater than 90 degrees).

Another test similar to the Thomas test that is used to assess whether there is a shortening of psoas consists of the following: placing yourself in standing position, grab one of your knees and raise it towards the chest. Now, at the point of maximum flexion, release it. It must hold above 90 degrees for 15 seconds so that there is no muscle shortening.

Modified Thomas test

With the new interpretations that have derived from the original Thomas test, one can also speak of a shortened anterior rectum, of an agreed sartorius or of a shortened fascia lata tensor.

  • If in the Thomas test position, the patient extend the knee and raise it above the hip, there is Psoas shortening.
  • If the patient keeps the knee at the height of the hip with knee extension (more pronounced than in the previous case) then we talk about anterior rectus shortened.
  • If, in addition, a presence is present external hip rotation then we will talk about shortened sartorius (the knee is positioned outward).
  • If one occurs hip abduction we will be talking about a shortening of the tensor fasia lata.

And here all we can tell you about the Thomas test. If you think you may suffer from a shortening of psoas or some other muscle of the upper leg, it is best to perform this test and check what the results say.

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