Hip Flexor Strain

Injuries > Hip & Groin > Hip Flexor Strain

(Also known as Hip Flexor Injury, Iliopsoas Strain, Psoas Strain, Hip Flexor Tear, Strained Iliopsoas Muscle, Torn Iliopsoas Muscle, Pulled Hip Flexor)

What is a hip flexor strain?

A hip flexor strain is an injury characterized by tearing of one or more of the hip flexor muscles and typically causes pain in the front of the hip or groin.

The group of muscles at the front of the hip are called the hip flexors. The most commonly involved muscle in a hip flexor strain is the iliopsoas (figure 1). The iliopsoas muscle originates from the lower back and pelvis and inserts into the thigh bone (femur).

The hip flexors are responsible for moving the knee towards the chest (i.e. bending the hip) during activity and are particularly active when sprinting or kicking. Whenever the hip flexors contract or are put under stretch, tension is placed through the hip flexor muscle fibres. When this tension is excessive due to too much repetition or high force, the hip flexor muscle fibres may tear. When this occurs, the condition is known as a hip flexor strain.

Tears to the hip flexors can range from a small partial tear whereby there is minimal pain and minimal loss of function, to a complete rupture whereby there is a sudden episode of severe pain and significant disability.

Hip flexor strains range from grade 1 to grade 3 and are classified as follows:

• Grade 1 Tear: a small number of fibres are torn resulting in some pain, but allowing full function.
• Grade 2 Tear: a significant number of fibres are torn with moderate loss of function.
• Grade 3 Tear: all muscle fibres are ruptured resulting in major loss of function.

The majority of hip flexor strains are grade 2.

Causes of a hip flexor strain

Hip flexor strains most commonly occur due to a sudden contraction of the hip flexor muscles (particularly in a position of stretch). They often occur during sprinting or kicking activities. This is particularly so during explosive acceleration or when a footballer performs a long kick, particularly following an inadequate warm-up.

Occasionally, patients may develop this condition gradually due to repetitive or prolonged strain on the hip flexor muscles. This may occur due to repetitive kicking or sprinting excessively. Hip flexor strains are commonly seen in running and kicking sports such as football and soccer.

Signs and symptoms of a hip flexor strain

Patients with this condition usually feel a sudden sharp pain or pulling sensation in the front of the hip or groin at the time of injury. In minor strains, pain may be minimal allowing continued activity. In more severe cases, patients may experience severe pain, muscle spasm, weakness and an inability to continue the activity. Patients with a severe hip flexor strain may also be unable to walk without limping.

Patients with this condition usually experience pain when lifting the knee towards the chest (especially against resistance) or during activities such as running, kicking or going upstairs. It is also common for patients to experience pain or stiffness after these activities with rest, especially upon waking in the morning. Swelling, tenderness and bruising may also be present in the hip flexor muscles. In cases of a grade 3 tear a visible deformity in the muscle may be evident.

Diagnosis of a hip flexor strain

A thorough subjective and objective examination from a physiotherapist is usually sufficient to diagnose a hip flexor strain. Further investigations such as an X-ray, Ultrasound, MRI or CT scan may be required to confirm diagnosis and exclude other pathology. In severe cases, particularly adolescents, an x-ray may be advisable to exclude the possibility of an avulsion fracture.

Treatment for a hip flexor strain

Most patients with this condition heal well with appropriate physiotherapy. The success rate of treatment is largely dictated by patient compliance. One of the key components is that the patient rests from ANY activity that increases their pain until they are symptom free (crutches may be required). Activities which place large amounts of stress through the hip flexors should be minimized, particularly running and kicking activities. Rest from aggravating activities ensures the body can begin the healing process in the absence of further tissue damage. Once the patient can perform these activities pain free, a gradual return to these activities is indicated provided there is no increase in symptoms.

Ignoring symptoms, or adopting a 'no pain, no gain' attitude is likely to lead to the problem becoming chronic. Immediate, appropriate treatment in patients with a hip flexor strain is essential to ensure a speedy recovery. Once the condition is chronic, healing slows significantly resulting in markedly increased recovery times and an increased likelihood of future recurrence.

Diligently icing the hip flexors in the initial phase of injury (first 72 hours) will greatly assist in improving recovery time. This should generally be applied for 20 minutes every 2 hours and should be guided by the treating physiotherapist. Anti-inflammatory medication may also help to reduce inflammation, pain and swelling. The use of crutches when walking may be necessary to protect the hip flexor muscles from further damage and to hasten the healing process.

A graduated flexibility and strengthening program guided by a physiotherapist is essential to recondition the hip flexor muscles and reduce the likelihood of injury recurrence. Careful assessment by the physiotherapist to determine which factors have contributed to the development of the condition, with subsequent correction of these factors is also important to ensure an optimal outcome.

A graduated return to running program in the final stages of rehabilitation is required to recondition the hip flexor muscles for running in a safe and effective manner. This should include the implementation of progressive acceleration and deceleration running drills before returning to sport.

Prognosis of a hip flexor strain

With appropriate management, patients with a minor hip flexor strain can usually recover in one to three weeks. With larger tears, recovery may take four to eight weeks or longer depending on the severity. Complete ruptures of the hip flexor muscles are rare and are usually managed conservatively. In these cases, recovery may be significantly longer.

Contributing factors to the development of a hip flexor strain

There are several factors which can predispose patients to developing this condition. These need to be assessed and corrected with direction from a physiotherapist. Some of these factors include:

• muscle weakness (particularly of the quadriceps, hip flexors or gluteals)
• muscle tightness (particularly of the hip flexors, quadriceps, hamstrings or gluteals)
• inappropriate training
• inadequate warm up
• joint stiffness (especially the lower back, hip or knee)
• poor biomechanics
• poor posture
• inadequate rehabilitation following a previous hip flexor injury
• decreased fitness
• fatigue
• poor pelvic and core stability
• neural tightness
• muscle imbalances

Physiotherapy for a hip flexor strain

Physiotherapy for patients with a hip flexor strain is vital to hasten the healing process, ensure an optimal outcome and reduce the likelihood of recurrence. Treatment may comprise:

• soft tissue massage
• electrotherapy (e.g. ultrasound)
• joint mobilization (especially the lower back and hip)
• stretches
• dry needling
• anti-inflammatory advice
• the use of crutches
• ice or heat treatment
• progressive exercises to improve strength and flexibility (particularly of the hip flexors)
• education
• biomechanical correction
• activity modification advice
• establishment of an appropriate return to activity or sport plan

Other intervention for a hip flexor strain

Despite appropriate physiotherapy management, some patients with a hip flexor strain do not improve adequately. When this occurs, the treating physiotherapist or doctor can advise on the best course of management. This may include investigations such as an X-ray, ultrasound, CT scan or MRI, or referral to appropriate medical authorities who can advise on any intervention that may be appropriate to improve the condition.

Exercises for a hip flexor strain

The following exercises are commonly prescribed to patients with this condition. You should discuss the suitability of these exercises with your physiotherapist prior to beginning them. Generally, they should be performed 3 times daily and only provided they do not cause or increase symptoms.

Hip flexion

Begin this hip strengthening exercise standing at a bench or table for balance (figure 2). Slowly lift your knee up as high as you comfortably can while keeping your back straight and tightening the muscles at the front of your hip (hip flexors). Hold for 2 seconds and repeat 10 times as far as possible pain free.

Figure 2 – Hip flexion (right leg)

Hip Flexor Stretch

Begin in the lunge position, with the leg to be stretched behind you. Keeping your back straight and buttock muscles contracted, gently lunge forwards until you feel a stretch in the front of your hip or as far as you can go without pain (figure 3). Hold for 15 seconds, 4 times at a mild to moderate stretch pain-free.

Figure 3 – Hip flexor stretch (right leg)

Find a Physio for a hip flexor strain

Find a physiotherapist in your local area who can treat a hip flexor strain.

Physiotherapy products for a hip flexor strain

The most commonly recommended products by physiotherapists to hasten healing and speed recovery in patients with this condition include:

1. Crutches
2. Ice packs
3. Heat packs

Click here to purchase physiotherapy products for a hip flexor strain.

Other exercises

For more hip flexor stretches click here.

For more hip strengthening exercises click here.

For basic Pilates exercises to improve your core stability and posture click here.

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