What Is the Psoas's Major Function?

Medically Reviewed by Jabeen Begum, MD on November 25, 2021
4 min read

Your psoas muscles are the main muscular connection between your torso and lower body. Their major function is to help flex your hip joint by bringing your leg up and in toward your torso. They also help strengthen your lower spine, which lends support to your posture. 

Your psoas muscles are long — up to 16 inches. They extend from each side of your lower spine through your hips and connect to your upper thigh bone, called the femur. You use them every day when you:

  • Stand 
  • Walk
  • Run
  • Jump
  • Dance
  • Maintain an upright posture

Psoas syndrome is the result of damage to your psoas muscle. It’s rare and commonly misdiagnosed. 

Other names for this syndrome include Jumper’s Hip and Dancer’s Hip. 

Psoas syndrome can occur on its own or as a secondary injury in cases of bursitisosteoarthritis, or rheumatoid arthritis in the hip. It’s commonly seen in athletes and people who have had a total hip replacement surgery.  

There isn’t any particular cause for all cases of psoas syndrome. The injuries tend to be caused suddenly — known as an acute injury— or from overuse of the muscle. 

Some common causes include: 

  • Repetitive jumping — for example, jumping rope and long jump activities
  • Long, frequent periods of sitting — which cause the muscle to shorten and tense up — followed by physical activity 
  • Complications from surgery

Sports with a lot of jumping are the most likely to cause a psoas muscle injury.

The exact symptoms of psoas syndrome depend on the severity of your injury.  

Psoas muscle pain is the most common symptom. Other symptoms include: 

  • Lower back pain
  • Pain in your pelvis
  • Pain radiating down to your knee
  • Difficulty walking — including limping or shuffling
  • Difficulty maintaining a fully upright position 

If pain is one of your symptoms, it’ll tend to get worse when you’re walking or moving in other ways that use your psoas muscle.  

Also, if your psoas muscles remain weak or injured for a long time, your surrounding muscles and tendons will have to do more work to compensate. This can lead to more injuries — each with their own symptoms and treatments. 

Most of these symptoms, particularly lower back pain, are common among all injuries to your hips and lower back. Your doctor will need to make a careful inspection of your body and symptoms before diagnosing you with psoas syndrome. 

Treatment of psoas syndrome depends on how severe the injury is and if there are any other injuries in this region. In most cases, the main treatment is to use physical therapy to stretch and strengthen your psoas muscle. 

There are very specific exercises that your physical therapist will use to work with this muscle. Note that some of these are dangerous to try on your own, since you can cause further damage to the region. 

You can try other exercises at home — like those described below — to speed up your recovery process. Most people with psoas syndrome will completely recover all normal function and be able to resume athletic activities after a set amount of time in physical therapy. 

Over-the-counter pain relievers — like ibuprofen and acetaminophen — can help manage your pain while you spend time in physical therapy. 

In some cases, you’ll need corticosteroid shots in your psoas muscle to help your healing process. In cases of psoas syndrome that develop after a total hip replacement, 50% of people will need corticosteroid shots to recover. 

Surgery is the rarest treatment option for psoas syndrome. Even in patients who have had a total hip replacement, only 12% of cases will need surgery. This percentage is much lower in otherwise-healthy athletes. 

The exact surgical procedure will depend on the extent of your injury. Examples include the need to surgically release your psoas tendon — which supports the muscle — or to lengthen the muscle itself. 

You should have two goals when doing at-home exercises for your psoas muscle: to stretch it and to strengthen it.

Lunges are a great example of an exercise that stretches your psoas muscle. To do a lunge:

  • Get into a lunge position — i.e., with the hip you want to stretch out behind you and your other leg bent in front of you at the knee.
  • Keep your torso upright and your chest facing forward.
  • Gently press your hips and torso forward without moving your back knee. 

Leg lifts are a safe way to strengthen your psoas muscle. To do leg lifts: 

  • Lay flat on your back with your arms extended out to both sides. 
  • Keep your knees slightly bent and lift your legs up until they’re at a right angle with the floor. 
  • Lower your legs but stop about an inch before you touch the floor.
  • Repeat the lift 10 times, or as much as your physical therapist recommends.