What Causes Stress Fractures in Runners, and Can You Prevent Them?

What are the symptoms of a stress fracture?

The main symptom is an aching pain in one area. It gets worse with activity and better with rest. Early on, the discomfort may only come towards the end of a run. If it is left unchecked, it can progress until simply putting weight on the leg becomes painful.

Stress fracture or shin splints? Shin splints (medial tibial stress syndrome) cause a wider, spread-out ache along the inner shin. A shin stress fracture causes sharper, pinpoint pain in one spot. Both are bone stress injuries on the same spectrum. So shin splints that do not get better can sometimes progress to a stress fracture.

What causes stress fractures in runners?

Stress fractures happen when repeated loading is more than the bone can handle while it rebuilds itself. Several factors combine to push a runner past that limit.

When these factors overlap, the risk multiplies. Picture a runner with a subtle leg length discrepancy who suddenly steps up marathon training. That runner is loading one leg harder than the other, thousands of times per run. That is the recipe for a bone stress injury that keeps coming back on the same side.

How is a stress fracture diagnosed?

MRI is the first-line imaging test when an acute stress fracture is suspected. It is highly sensitive. It can detect bone oedema (swelling inside the bone) before a crack shows on X-ray, and it shows soft-tissue detail around the injury.

Plain X-rays often miss early stress fractures, because the crack may not be visible for several weeks. A standard X-ray is also taken lying down. This means it cannot show how your bones line up under your body weight. That matters once the acute injury has healed and you want to understand why it happened.

How does whole-body alignment affect stress fracture risk?

Your skeleton is a connected chain from your feet to your head. When one link is out of position, other areas make up for it. A tilted pelvis, a difference in leg length or a rotational imbalance in the hip can redirect impact forces. Then one bone takes far more load than it should.

This kind of uneven loading only shows up when you are standing and bearing weight. Lying-down imaging, including standard X-ray, CT and MRI, relaxes the muscles and removes gravity. The tilt or rotation that drives uneven forces through your legs more or less disappears on the scan.

That is where ScanAlign standing EOS imaging comes in. An EOS scan captures your whole skeleton from head to feet in one upright image. It uses about 90% less radiation than a standard X-ray, around ten times less. It shows how your pelvis, hips, knees and feet line up with each other under real weight-bearing conditions, the same conditions you run in.

How can runners prevent stress fractures?

Prevention comes down to matching the load you put through your bones with what those bones can handle. Most advice focuses on the load. But alignment, meaning how evenly that load is spread, is just as important for runners who keep getting injured.

For wider advice on lowering your risk of running injuries, read our page on sports injury prevention.

What about stress fracture recovery time?

Recovery depends on where the fracture is and how severe it is. Most stress fractures need several weeks of reduced loading, sometimes longer for high-risk sites like the navicular bone. Your treating clinician will guide your plan for getting back to running. For long-term prevention, what matters is finding the factors that caused the fracture, so you can address them before you return to full training. If alignment played a role, the same forces will still be there when you start running again.

So before you start treatment, or change the one you are on, it is worth getting a detailed diagnosis. Knowing whether the cause sits in your pelvis, your legs or your spine changes what will actually help.

Frequently asked questions about stress fractures