Exertional compartment syndrome

What is exertional compartment syndrome?

Exertional compartment syndrome (the full clinical name is chronic exertional compartment syndrome, or CECS) is leg pain that builds up during repetitive exercise such as running or cycling¹². It usually eases within minutes of stopping, and you have no symptoms at rest¹³.

The idea is that pressure rises inside a compartment (a closed section of muscle) during exercise and takes longer than usual to settle³. That may reduce blood flow and cause pain³.

It mainly affects young, active people aged 15 to 25, often in both legs². It is underdiagnosed, and it isn't clear yet how common it is². Not all exercise-related leg pain is this⁴.

What causes it, and who gets it?

The exact cause isn't known¹³, and the underlying cause is poorly understood⁵. Muscles may swell during exercise so the fascia (the covering around the muscles) becomes too tight, causing an aching pain that can turn sharp if you keep going⁶. Other ideas include tiny injuries to the muscle, muscle disease, reduced blood supply, a stiff fascia and muscle growth³.

The condition is most often seen in young people who exercise regularly and repetitively, for example by running or cycling¹. Men and women were both common among those treated, so neither sex can be called clearly higher risk⁷⁸.

Because no particular cause is proven, there's no need to change your shoes, technique or training on a guess.

What does it feel like, and how is it diagnosed?

The usual pattern is cramping pain (most often in the legs), swelling or a visibly bulging muscle, and tingling, which builds gradually during exercise and eases with rest¹. Athletes may first notice pain once they have exercised for a predictable stretch, typically about 20 minutes (range 15 to 30), with the pain easing within several minutes of resting⁹.

A careful history is the most important part of the assessment⁴¹⁰. You'll be asked when it starts, what brings it on or eases it, and whether it disturbs your sleep⁴. Other causes, such as bone, nerve or blood-flow problems, have to be separated out⁴.

Pressure testing is sometimes used to confirm it, but its criteria are unreliable, so it shouldn't be relied on alone⁴¹⁰.

What helps first?

Care usually starts without surgery, which is called first-line care⁴¹¹¹². It often means cutting back on or changing the activity that brings the pain on, and switching to something less strenuous for now¹¹¹²¹. A physiotherapist can also help with gait retraining (changing how you walk or run) and with other factors that overload your legs⁴¹².

Other options include massage, taping, stretching, strengthening, shoe changes and orthotics¹³³. Anti-inflammatory medicines for pain may help too¹³. A GP or pharmacist can advise whether they suit you.

These measures mainly ease symptoms by resting the muscle, rather than fixing the underlying problem³. It isn't clear yet how well any one of these options works¹³.

Agree a plan with your clinician, including how long you'll trial it and how you'll judge whether it's working. Active treatment is advised once the condition is diagnosed because it may not improve on its own¹³, though whether rest alone is enough isn't clear yet¹³¹⁴, so agree a plan with a clinician instead of relying on rest alone¹³.

What helps if that isn't enough?

If first-line care hasn't worked, surgery may be considered: a fasciotomy (release of the tight fascia)⁴. It may give higher satisfaction and return to activity than care without surgery, though this isn't certain¹³. Botulinum toxin injections are promising but still debated³.

Surgery is planned after assessment, not an emergency³⁴. Referral to an orthopaedic or sports medicine doctor may be offered to discuss options. Before any surgery, the surgeon can discuss expected outcomes for a person's situation, risks, recovery time and rehabilitation.

How long does it take, and can it come back?

Outcomes vary widely, so it's hard to predict how any one person will do¹³. Rest can lessen the symptoms, and for many people the condition settles on its own without further treatment¹⁴. Care without surgery mainly eases symptoms by resting the muscle, rather than curing the underlying cause³.

It isn't clear what stops it coming back, so no prevention strategy can be promised. When you return to activity, build up gradually and agree a plan with your treating clinician.

What can make it serious?

• Your foot feels very swollen and tight and the pain keeps getting worse, even with pain relief and raising it, after an injury or operation or in a cast.