What Is a Hip Flexor Strain?

A hip flexor strain, also called a pulled hip muscle, refers to an injury of the hip muscles. The hip flexors are made up of a group of muscles including the iliacus and psoas major (iliopsoas), and rectus femoris (part of the quadriceps). The hip flexor muscles help you raise your knee to your body. If the muscles get overworked or overused, it may lead to a hip flexor strain.

The typical cause for a hip flexor strain is overuse. Other causes of a hip flexor strain are sitting for long periods of time, weakness in the muscles surrounding the hip flexor, or acute contraction of the muscle. Symptoms range from mild to severe and can impact mobility. The most common symptom of hip flexor strain is sudden hip pain.

Signs and Symptoms

There are several symptoms of a hip flexor strain. Symptoms include:

• Sudden onset of sharp pain to the front of the hip 
• Increasing pain as you try to lift your knee to your chest
• Cramping or clenching feeling of the muscles in your thigh or upper leg area
• Painful when stretching 
• Tenderness or soreness in your upper leg
• Muscle spasms in hip or thigh
• Reduced mobility, discomfort or limping
• Weakness or loss of strength in the front part of the groin along with a tugging sensation
• Swelling or bruising in the hip or thigh area
• Stiffness or tightness after being sedentary (sleeping or sitting)
• May feel pain when walking or running
• Inability to kick, jump, or sprint

Symptoms may range in levels of severity. It is important to consult your healthcare provider if you are noticing symptoms.

Causes

There are several different causes for a hip flexor strain. Some people are more prone to hip flexor strains than others. Activities that may increase the risk of a hip flexor strain are cycling, running, soccer, dancing, martial art, or any sport or activity that requires repetitive jumping or kicking. 

Other factors that may increase the risk for a hip flexor strain are sitting for long periods of time, not warming up appropriately, weak muscles, stiff muscles, trauma or falls. Certain deep stretches may also increase the risk of a hip flexor strain. 

A hip flexor strain is an actual tear in the muscle fibers. The strains are categorized into three grades or levels of severity in tearing. The three grades range from mild to severe symptoms. Grade two tears are the most common. The grades include:

• Grade 1. This is a minor tear, where only a few muscle fibers are damaged.
• Grade 2. A moderate amount of muscle fibers has been damaged and there is potential for a loss of function or mobility in the hip flexor.
• Grade 3. The muscle fibers have completely torn, and it would be difficult to walk or move without limping.

Diagnosis 

To make a diagnosis, your doctor will conduct a physical exam, checking for issues with pain and range of motion. Your doctor may ask you to perform specific movements, trying to pinpoint the source and severity of the issue. They will also collect a symptom history. If further assessment is needed, your doctor may recommend an x-ray to rule out a hip fracture. 

Treatment

Most hip flexor strains do not require intensive treatment or surgery. If the pain persists after 10-14 days, consult with your healthcare provider for further assistance and treatment options. Treatment for most hip flexor strains can be done at home. Treatments include:

• RICE (rest, ice, compression, elevation)
• Decrease or stop any strenuous activity that is causing or increasing pain for two weeks
• Taking over-the-counter anti-inflammatory medications to reduce pain and inflammation (Ibuprofen, Advil, Naproxen) 
• Wearing a brace helps to stabilize the injury and reduce inflammation
• Light and gentle stretching (make sure to avoid deep or aggressive stretches)
• Alternating heat and ice packs
• Exercises that build strength in the hips and surrounding muscles
• Physical therapy and rehabilitation (this treatment is typically only used if the pain has gotten worse or not improved in 10-14 days)
• Platelet-rich plasma (PRP) injection (expedites healing through injecting the patient’s own blood into the hip)

If the pain has worsened or has not improved in 10-14 days, your doctor may recommend taking x-rays or doing an MRI or CT scan in order to rule out other issues or conditions, such as a hip fracture.