Runners with anterior compartment syndrome experience pain in the front of their leg. This is different from shin splints which are usually felt in the middle of the lower leg.

When muscles swell during exercise they put pressure on the sheath of connective tissue that surrounds them. If this sheath is too tight then pain, numbness or weakness develops.

How It Happens

Compartment syndrome happens when pressure builds up around groupings of muscles called compartments. These muscle groups are covered by a tough membrane called fascia. When a person exercises, the pressure in the compartments increases. Eventually, the increased pressure can damage muscles, nerves and blood vessels within the compartment. If the pressure gets too high, a condition called acute compartment syndrome can develop. It is a medical emergency that can lead to permanent muscle injury and loss of function.

Chronic exertional compartment syndrome is a less dangerous but still serious condition that can cause long-term pain and problems. It can happen to anyone who exercises a lot or to people with physically demanding jobs. People who have diseases that affect blood circulation are at higher risk for developing chronic compartment syndrome.

The condition most often occurs in the muscles of the lower leg and foot. It affects the anterior compartment of the tibialis anterior muscle on the front of the shin, which helps move your toes and feet toward the shin (dorsiflexion). It can occur if you change your running style, increase your training volume or intensity too quickly or do not rest enough in between workouts. It can also be caused by a direct blow to the muscle or if you have an infection.

Most of the time, this condition is preventable. The main way to do this is to listen to your body. Don’t push yourself to exercise when you’re in pain. Rather, talk to your healthcare provider and find ways to reduce the pressure on your muscle compartments.

Taking regular walking breaks during your run can help relieve compartment syndrome symptoms by giving the muscles that are overworking and swelling a chance to get some air. You can also try to change your running style to land on the forefoot instead of the heel with each stride. Some research suggests that doing this can decrease the elevation of compartment pressures during running and reduce your risk for developing CECS. In addition, a regular routine of self-massage with a tennis ball or foam roller can help with recovery.

Symptoms

The muscles of your lower leg are grouped into areas called compartments that are separated by a thin membrane, fascia. When you exercise, the muscles within each compartment swell and push against the fascia more than normal. When this happens the pressure builds up and restricts the flow of fresh blood, oxygen and nerves into the muscle. This can lead to pain, tightness, numbness or weakness in the affected area. The condition can cause extreme pain and may be a medical emergency.

Chronic compartment syndrome usually occurs in one of the four muscle compartments in your lower leg (as opposed to acute compartment syndrome which is a medical emergency and only affects the anterior compartment). It typically comes on gradually from exercise and continues to get worse over time.

Symptoms include:

Pain in the front of your shin or lower leg. This can range from mild to intense and often tracks down into your foot. Tightness in the calf and tibialis anterior muscles. This can feel like a knot or band that keeps getting tighter and harder to break loose. Numbness or tingling in your lower leg or foot. This is caused by the loss of circulation to the muscles and may be present on both sides of the leg or only in certain positions.

Other injuries that can cause similar symptoms are medical tibial stress syndrome (shin splints) and a stress fracture, but these injuries cause pain on the shin bone, not deep in the shin muscles. An MRI can help to rule out these types of injuries and to confirm a diagnosis of compartment syndrome.

In some cases symptoms will improve if you stop running or exercising for a few days. However, this is only a temporary relief and the symptoms will return once you start up again. Changing to a forefoot or midfoot running style can also reduce the symptoms and in some cases eliminate them completely. Our physiotherapists can teach you the appropriate running technique to use and will assist you in making this change. If conservative measures fail surgery is available to relieve the pressure in the compartments by cutting the fascia open with a procedure called a fasciotomy.

Diagnosis

Acute compartment syndrome happens very quickly, often after a severe injury. It is a medical emergency and, if not treated immediately, can lead to permanent disability and death. In acute compartment syndrome, pressure increases to dangerous levels in the muscle and nerve compartments. This prevents blood from reaching the cells, decreasing tissue function and causing pain. The pressure can be relieved by reducing the activity that caused it and by using a device called a fasciotomy.

Chronic compartment syndrome is less urgent but can still be very painful and debilitating. It usually builds up slowly over time due to exercise or repetitive activities. The doctor may measure the pressure in the compartments and if it is very high, recommend surgery to alleviate the pressure.

Runners who are diagnosed with compartment syndrome will need to rest. This includes avoiding the exercise or activity that caused it. It is also helpful to change up the type of exercise or where you do it. For example, running on a track instead of concrete or changing your form from heel strike to toe run can make a difference. If symptoms persist, a physical therapist can teach you how to strengthen and stretch your affected muscles.

In addition to rest, ice and compression, the most effective treatment for compartment syndrome runners is to have the doctor perform a fasciotomy. This is a procedure that cuts the fascia to allow more room for swelling in the compartments. It can be done in the office or the hospital, and usually takes 6 hours to completely restore blood flow to the foot and leg.

Symptoms of compartment syndrome are most commonly related to overuse injuries in a runner, especially from doing too much or too fast training. However, the anatomical structure of the compartments in the leg and feet is believed to play a role as well. The most effective preventive strategies are to focus on proper biomechanics and a balanced training program. This includes wearing proper shoes, using the right type and amount of recovery between workouts, and focusing on balance, agility, and strength training to prevent muscle imbalances.

Treatment

If untreated, compartment syndrome can progress to a life-threatening condition called calcific myonecrosis. This is a medical emergency when irreversible muscle and nerve damage occurs due to a mismatch between compartment pressure and blood flow resulting in tissue death.

If you have chronic compartment syndrome, your doctor may recommend physical therapy to help prevent symptoms from returning and, in some cases, a procedure called a fasciotomy. This involves making slits in the compartments of your lower leg to give them more room to expand when you exercise.

For many runners, this will reduce pain and improve their ability to continue exercising without worsening their symptoms. Your doctor may also recommend orthotics, shoe inserts that support your foot and leg.

Changing your running style is also a common treatment for anterior compartment syndrome runners. Most runners with this injury have a heel-striking running style and, over time, retraining to a midfoot or forefoot striking running style can help you return to your regular exercise routine without experiencing symptoms of this disorder.

When retraining to a new form, it is important to do so gradually, and under the supervision of your physician or physical therapist. This is important, as it may take weeks or months for your body to adapt to the increased demands on the muscles of your lower leg.

Another option for reducing pressure in the lower leg is to use compression socks or wraps, available at your local sports store. In some cases, this can also decrease calf muscles tension, which can be a contributing factor to the development of anterior compartment syndrome.

A weak core can contribute to imbalanced forces on the lower leg during exercise, so it’s important to strengthen the muscles of the hips and abdomen. This can also decrease the stress on your legs and feet, and will help you avoid overuse injuries like compartment syndrome.

Both compartment syndrome and shin splints are overuse injuries that happen when you increase the amount of exercise or intensity too quickly or don’t adequately warm up or stretch before you exercise. Your doctor will discuss ways to decrease your chances of these overuse injuries, including cross training and incorporating more low-impact exercises into your workouts, and will advise you on how to best protect your legs and feet while you are exercising.