What is a hip flexor strain

A hip flexor strain or a ‘pulled hip flexor’, occurs when one of the hip flexor muscles (iliacus and psoas major muscles) supporting the hip joint is stretched beyond its limit or torn. The hip flexor muscle is actually made up of ‘two main’ muscles – the iliacus and psoas major muscles, commonly known as iliopsoas muscle. The hip flexor muscles (iliacus and psoas major muscles) run from the back of the lower spine to the front of your thigh (see Figure 1). Hip flexors help you move, or flex, your leg and knee up towards your body. Sudden movements, such as sprinting, kicking, and changing direction while running or moving, can stretch and tear the hip flexors. Strains of the hip flexor muscle usually occur as a result of an overload of the muscles, or trying to move the muscles too fast (as when kicking forcefully playing football). Runners, people who do martial arts, and football, soccer, and hockey players are more likely to have this type of injury.

The difference between a strain and a sprain – is that a sprain is an injury to a ligament, while a strain is an injury to a tendon or muscle.

The risk of muscle strain increases if you:

• have previously injured your hip muscles
• do not warm up properly before exercising
• attempt to do too much too quickly

Other factors that can lead to hip flexor strain include:

• Weak muscles
• Not warming up
• Stiff muscles
• Trauma or falls

Like all muscle strains, they may be graded as mild (grade 1) moderate (grade 2) or severe, complete tears (grade 3). A severe hip flexor strain can limit your ability to move your hip.

The severity of symptoms associated with hip flexor strain depends on the severity of the strain. Muscle strains are categorized into ‘grades 1-3’ which gives an indication of the degree of muscle injury. The grading system is as follows:

1. Grade 1 strains involve minor tearing of muscle fibers with only minimal or no loss in strength. Pain is usually mild to moderate with no defect in the muscle tissue when examined by a doctor.
2. Grade 2 strains involve more severe disruption to the muscle fibers with significant pain and loss of strength. A defect in the muscle tissue may sometimes be felt by your doctor.
3. Grade 3 strains are a result of complete tearing of the muscle with associated severe pain and complete loss of strength. A defect in the muscle tissue can frequently be felt by your doctor on examination.

Recovery is longer with a high-grade injury, and the long-term outcome is potentially worse.

You will feel a hip flexor strain in the front area where your thigh meets your hip. Depending on how bad the strain is, you may notice:

• Mild pain and pulling in the front of the hip.
• Cramping and sharp pain. It may be hard to walk without limping.
• Difficulty getting out of a chair or coming up from a squat.
• Severe pain, spasms, bruising, and swelling. The top of the thigh muscle may budge. It will be hard to walk. These are signs of a complete tear, which is less common. You may have some bruising down the front of your thigh a few days after injury.

Although many hip flexor strains improve with simple home treatment, severe strains may require physical therapy or other medical treatment. You may need to use crutches for a severe strain.

Figure 1. Hip flexors

Hip flexor strain causes

A muscle strain occurs most commonly when a muscle is stretched whilst it is contracting. This type of contraction is termed ‘eccentric contraction’. If you think about placing a heavy object on the table, your biceps are contracting whilst lengthening. This allows controlled movement as you place the object. The same type of muscle contraction occurs in the hip whilst you are running, kicking or jumping. During these actions, the muscle can stretch too far whilst it is contracting and lead to a muscle strain.

Hip strains usually occur in sporting activities that require the hip to move through a big arc such as kicking or where the legs are lifting a heavy load such as in a rugby scrum. If a muscle is tight due to overuse or not warming up properly, then this can lead to straining the muscle during sports or activities that would normally not lead to an injury.

Another cause of hip strain is repetitive trauma. Distance runners are susceptible to hip strains due to the stress exerted on the hip muscles. The frequency and duration of their running means that the hip muscles can become progressively tight and eventually this can lead to a muscle strain.

Risk factors for hip flexor strain

The following are risk factors for hip strains:

• Not warming up correctly: If you do not warm up the hip muscles prior to playing sports which involve large hip movements, there is an increased risk of suffering a hip strain. Prior to exercise, a sport specific warm up should be performed including gentle stretching, sub-maximal cardio workout and range of motion exercises.
• Previous injury: A hip strain that has either not fully healed or left residual scar tissue may predispose to a further hip strain in the future
• Sports activities which hold a risk of hip strains include football, soccer, rugby, basketball, and long distance running or sprinting.

Hip flexor strain prevention

Prevention of hip strains requires a focus on good flexibility and strength of the muscles of the hip. By following a few simple rules, the likelihood of hip strains can be reduced:

• Stretching should always be performed before and after sport.
• A warm up should be performed prior to sport which should involve some simple sport specific drills and range of motion exercises (eg. leg swings, jogging, jumping, direction changes whilst jogging, if playing soccer/football)
• Make sure the muscles of the hip are well conditioned through strengthening programs

Hip flexor strain symptoms

The following are general symptoms of hip strains:

• Pain. Depending on which muscle is affected, the pain will be felt in different areas. For hamstring strains, the pain is usually felt in the back of the thigh or buttock area. For adductor strains, the pain will be felt in the groin and for hip flexor strain, the pain will be felt in the front of the hip or groin. Usually moving the hip will aggravate the pain, as will pressing on the affected muscle.
• Weakness. The strained muscle may feel weak. This can lead to a sensation of losing power in the legs and may lead to a limp developing.
• Swelling. There may be swelling over the site of the hip strain. Bruising may also be present.

The symptoms of a hip flexor injury can be graded 1, 2 or 3 depending on severity. A grade 1 injury could consist of a ‘stretch’ of the muscle or a small micro tear in the muscle. A grade 2 injury could be a partial tear in the muscle and a grade 3 injury is usually a severe, complete rupture of the muscle. The player feels a grade 2 or grade 3 injury as a sudden pain the hip region during an activity requiring explosive muscle contraction (for example sprinting or kicking in soccer). There is local pain and tenderness and, if the strain is severe, swelling and bruising.

Grade 1 hip flexor injury symptoms

The player may have tightness and pain in the front and very top of their thigh during a game but will still be able to walk properly. The player will usually notice the injury after cooling down or the following day. The player probably won’t have much swelling, but will have trouble or some mild pain when sprinting, kicking a football or changing direction quickly. Often the player may be able to finish the game.

Grade 2 hip flexor injury symptoms

During training or a game, the player may notice a ‘sharp pull’ or ‘cramp’ in the front and very top of their thigh. The player may feel they have ‘strained their groin’. The player will probably be unable to walk properly and will not be able to sprint or kick a football effectively.

Grade 3 hip flexor injury symptoms

The player will often feel a severe pain in the front and very top of their thigh while kicking or sprinting, which will almost always stop the player from playing. A static contraction of the muscle will be painful and might produce a bulge in the muscle. A player will be in severe pain and will notice swelling. However, complete tears of the hip flexor muscle are uncommon. In the long-term, they heal well with physiotherapy.

Hip flexor strain complications

If a hip strain is not properly treated, or a return to sport is made before the injury has had enough time to recover, the hip strain can become chronic. This means that there is ongoing pain in the hip area requiring prolonged rehabilitation.

Hip strains may leave the affected muscle slightly weaker or slightly tighter than prior to the injury. This can predispose to straining the same hip again in the future. It is important to complete the full course of treatment and rehabilitation laid out by your doctor or physiotherapist in order to minimise this risk.

Symptomatic fibrosis (or scarring) occurs less frequently. In some athletes, how-ever, a severe muscle strain injury will result in a painful area of scarring or fibrosis. Treatment for this complication should involve physical therapy with stretching and perhaps the use of modalities such as ultrasound and deep-tissue massage. Very occasionally, surgical intervention is required to remove the area of scar tissue.

Hip flexor strain diagnosis

Hips strains are initially diagnosed through a thorough history and examination. It is important to tell the doctor when the pain was first felt and the exact movement that was being performed at that time. Once a history of the injury has been taken, the doctor will examine the hip. They may palpate (apply pressure) different areas of the hip looking for pain in order to see which muscle might be affected. They may also ask you to perform various movements to determine which muscle is affected.

Usually strains can be diagnosed in a clinical setting without the need for further investigations. Sometimes if it is unclear as to whether the problem is a hip strain or a stress fracture, an X-ray may be considered. Occasionally in order to determine the extent of the strain, an ultrasound or MRI may be performed which may help in defining the muscle strain. This is rarely necessary however.

How to treat hip flexor strain

Hip strains generally recover well. The goals of treatment are to minimise the pain, allow the muscle to heal and then restore normal range of motion and strength. This treatment follows a stepwise process:

Initial treatment – rest and recovery

Follow these steps for the first few days or weeks after your hip flexor strain:

• Rest. Stop any activity that causes pain.
• Ice the area for 20 minutes every 3 to 4 hours for 2 to 3 days. DO NOT apply ice directly to your skin. Wrap the ice in a clean cloth first.

You can use ibuprofen (Advil, Motrin), or naproxen (Aleve, Naprosyn) to reduce pain and swelling. Acetaminophen (Tylenol) helps with pain, but not with swelling. You can buy these pain medicines at the store.

• Talk with your doctor before using pain medicines if you have heart disease, high blood pressure, kidney disease, or have had stomach ulcers or internal bleeding in the past.
• DO NOT take more than the amount recommended on the bottle or by your doctor.

Activity

Your doctor may recommend that as you rest the area, you do exercises that don’t strain the hip flexors, such as swimming.

The use of crutches when walking may be necessary to protect the hip muscles from further damage and to hasten the healing process. If the hip strain is minor, this may be all the treatment that is required. For more serious strains, a physical therapist may be required for rehabilitation of the area.

For a severe strain, you may want to see a physical therapist. Your physical therapist will work with you to:

• Stretch and strengthen your hip flexor muscles and other muscles that surround and support that area.
• Guide you in increasing your activity level so you can return to your activities.

If you are seeing a physical therapist, be sure to do the exercises as directed. Following a care plan will help your muscles heal and likely prevent future injury.

See your doctor if you do not feel better in a few weeks with treatment.

Hip flexor strain rehab

Passive and active range of motion exercises

A graduated flexibility and strengthening program guided by a physiotherapist may be necessary for more severe hip strains. 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. The rehabilitation will involve moving the hip, first passively and then actively. This means initially, the hip is moved either by someone else or using your arms to assist the movement such that the injured muscle does not work during these movements. Following this hip movements are performed using the muscles that have been injured.

Here are some examples of typical rehabilitation exercises for your hip flexor strain. Start each exercise slowly. Ease off the exercise if you start to have pain.

Your doctor or physiotherapist will tell you when you can start these exercises and which ones will work best for you.

Hip flexor strain exercises

Pelvic tilt with marching

1. Lie on your back with your knees bent and your feet flat on the floor.
2. Tighten your belly muscles and buttocks, and press your lower back to the floor.
3. Keeping your knees bent, lift and then lower one leg up off the floor, and then lift and lower your other leg like you are marching. Each time you lift your leg, hold that position for about 6 seconds before lowering your leg.
4. Repeat 8 to 12 times.

Scissors

1. Lie on your back with your knees bent at a 90-degree angle and your feet off the floor.
2. Tighten your belly muscles and buttocks, and press your lower back to the floor.
3. Slowly straighten one leg, and hold that position for about 6 seconds. Your leg should be about 30 centimeters off the floor. Bring that leg back to the starting position, and then straighten your other leg. Hold that position for about 6 seconds, and then switch legs again.
4. Repeat 8 to 12 times.

Hamstring stretch (lying down)

1. Lie flat on your back with your legs straight. If you feel discomfort in your back, place a small towel roll under your lower back.
2. Holding the back of your affected leg for support, lift your leg straight up and toward your body until you feel a stretch at the back of your thigh.
3. Hold the stretch for at least 30 seconds.
4. Repeat 2 to 4 times.

Quadricep and hip flexor stretch (lying on side)

1. Lie on your side with your good leg flat on the floor and your hand supporting your head.
2. Bend your top leg, and reach behind you to grab the front of that foot or ankle with your other hand.
3. Stretch your leg back by pulling your foot toward your buttock. You will feel the stretch in the front of your thigh. If this causes stress on your knee, do not do this stretch.
4. Hold the stretch for at least 15 to 30 seconds.
5. Repeat 2 to 4 times.

Hip flexor stretch (kneeling)

1. Kneel on your affected leg and bend your good leg out in front of you, with that foot flat on the floor. If you feel discomfort in the front of your knee, place a towel under your knee.
2. Keeping your back straight, slowly push your hips forward until you feel a stretch in the upper thigh of your back leg and hip.
3. Hold the stretch for at least 15 to 30 seconds.
4. Repeat 2 to 4 times.

Hip flexor stretch (edge of table)

1. Lie flat on your back on a table or flat bench, with your knees and lower legs hanging off the edge of the table.
2. Grab your good leg at the knee, and pull that knee back toward your chest. Relax your affected leg and let it hang down toward the floor until you feel a stretch in the upper thigh of your affected leg and hip.
3. Hold the stretch for at least 15 to 30 seconds.
4. Repeat 2 to 4 times.

Final stages – strength training

Initially exercises will be given that isolate and strengthen the injured muscle. Once the muscle regains its strength, a graduated return to running or sport specific activities is the final stage of rehabilitation to fully recondition the hip muscles. This should include the implementation of progressive acceleration and deceleration running drills before returning to sport.
Once there is full range of motion of the hip, full strength equal or greater than the uninjured leg, and you are able perform all of the fundamental skills of the required sport pain free, you are ready to return to sport.

Surgical treatment

Severe injuries in which the muscle fibers are completely torn may require surgery in order to return to normal function and movement. Surgery typically involves stitching the torn pieces back together.

Many severe hip strains are successfully treated without surgery. Your doctor will discuss the treatment options that best meet your individual health needs.

Hip flexor strain recovery

In most cases, you should avoid the activity that caused your injury for 10 to 14 days. A severe muscle strain may require a longer period of recovery. If your pain returns when you resume more strenuous activity, however, discontinue what you are doing and go back to easier activities that do not cause pain.

You can take the following precautions to help prevent muscle strains in the future:

• Condition your muscles with a regular program of exercise. Ask your doctor about exercise programs for people of your age and activity level.
• Warm up before any exercise session or sports activity, including practice. A good warm up prepares your body for more intense activity. It gets your blood flowing, raises your muscle temperature, and increases your breathing rate. Warming up gives your body time to adjust to the demands of exercise. It increases your range of motion and reduces stiffness.
• Wear or use appropriate protective gear for your sport.
• Take time to cool down after exercise. Instead of performing a large number of rapid stretches, stretch slowly and gradually, holding each stretch to give your muscle time to respond and lengthen.
• Take the time needed to let your muscle heal before you return to sports. Wait until your muscle strength and flexibility return to preinjury levels.

Hip flexor strain exercises to avoid

In most cases, you should avoid the exercises that caused your injury for 10 to 14 days.