Chronic Exertional Compartment Syndrome

Written by Onfit Tutor Claire Watson

Most of you would never have heard of Chronic Exertional Compartment Syndrome (CECS) as a sporting injury before, but as this injury has plagued me for some 8 years now, I thought it might be worth mentioning.


So what is Compartment Syndrome?

Normally classified under the umbrella term ‘Shin Splints’, it is a common shin or calf injury that predominantly presents in athletes who are distance runners (high mileage). This injury also presents in beginner runners who have a sudden increase in volume and intensity of running whilst not being conditioned properly. It is often confused with shin splints as the signs and symptoms can be very similar. The pain is brought on by activity, due to the anatomy of the muscles.

The lower leg is made up of four compartments (sections) of muscles, each are encased in a fascia (sheath of connective tissue) much like a ‘sausage’ in the skin. The anterior compartment is at the front between the Tibia (shin bone) and Fibula (splint bone). It contains the muscles that pull the foot and toes up towards the knee. The medial compartment is on the inside aspect of the shin. The muscles which bend the toes during pushing off are in this compartment. The posterior compartment is the largest, and contains the calf muscles which attach to the Achilles tendon and push the ankle downwards during running and jumping. The lateral compartment on the outside of the shin contains the muscles which turn the sole of the foot outward.

CECS Image 1



CECS occurs when the volume of the muscles, blood vessels and nerves become too big for the space within the compartment. This leads to an increase in pressure within the compartment and compresses all structures within the compartment. The main cause is an increase in muscle size in the compartment due to physical activity.


Signs & Symptoms

The major symptom is pain in the legs (muscle pain specifically) bought on by certain types of physical activity.  The pain usually will start within 10-20 minutes of running/jogging or fast extended-gait walking (marching).  Eventually, the pain and tightness felt will get so severe that the athlete/ participant will have to discontinue the activity. The pain is cramp-like and is due to the constriction of blood vessels which prevent blood and oxygen from reaching the muscles. This can lead to permanent tissue damage. Usually, however, the pain will only last a short time and will ease with rest. In some patients the increased pressure in the compartment can be felt as taut tension within the tissues. The lower leg will also look very taut and may appear to be very swollen and might have a bruised complexion due to constriction of blood vessels.



A GP (general practitioner) should be your first point of call. They will usually try to eliminate other injuries such as shin splints, stress fractures etc with a plain x-ray. If that doesn’t show anything, then an MRI scan and compartment pressure testing (which is done by inserting a catheter into the compartment and measuring pressure with a transducer before and during exercise) will confirm if it is in fact CECS.





In cases where the pain starts with exercise, and it goes away after rest, conservative treatment such as physiotherapy and the prescription of Orthotics (insoles) may reduce the severity of the symptoms, but cannot get rid of the problem. Once a diagnosis of CECS has been confirmed through measurement of raised compartment pressure, the most effective treatment is surgery.  This relieves the pressure on the tissues within the compartment.



After impact exercise/activity such as long distance walking/jogging/running, it’s always a good idea to have an ice bath or apply a ice or cold pack for roughly 20mins. This will reduce the pain and swelling which will take the pressure off the sheath surrounding the muscle. Deep tissue/sports massage can also help reduce swelling, pain and inflammation. Wearing of correct fitting footwear is equally important to ensure correct foot placement while striding. If an individual is not placing the foot correctly during activity, this could lead to muscle imbalances which could cause CECS from overuse.

If you notice pain and or discomfort in your lower legs during activity, then it is always better to visit your GP first before the injury gets worse. The quicker you act on this injury the better chance you have of being able to recover from it.