Everything you need to know about stress fractures – the cause, healing time and how to avoid them

How do you know if you have a stress fracture and what should you do if you have?


Not all running injuries are created equal. Whilst a stress fracture may sound fairly innocuous it can be incredibly painful and prevent you from running for several months.

If you had to pick something to keep you away from your beloved sport, you’d infinitely rather have woes with blisters or chafing, or even a mild strain, than the looming threat of the dreaded stress fracture. A relatively common injury, they often appear to come from nowhere and can sometimes be tricky to identify.

So what actually is a stress fracture, how does it differ from an outright break, and how can you do your very best to avoid ever getting one? Here’s our guide to everything you need to know.

What is a stress fracture, and where are runners most likely to get them?

A stress fracture is a small crack or break in an otherwise normal bone. Whereas most people break bones in a single traumatic event, like a fall, stress fractures are more often an overuse injury, developing from the repetitive action or forces involved in running. They usually occur when the capacity of the bone to absorb impact is simply overloaded. That might be, for example, because the bone isn’t strong enough, or because it’s been subject to too steep an increase in load.

‘Stress fractures occur when muscles become fatigued and are unable to absorb added shock. Eventually, the fatigued muscle transfers the overload of stress to the bone, causing a tiny crack called a stress fracture,’ explains Dr Matthew Oliver, consultant trauma and orthopaedic surgeon at Benenden Hospital, Kent.

The most important thing for runners is not to ignore early signs. If you have pain in a specific area – most commonly the shin bone (tibia) or the foot – that is gradually increasing, feels worse when weight is put on the injured area, but feels better at rest, then do not just hope for the best. The more you ignore these early signs, the more likely you are to get a full-blown stress fracture. Seek expert medical advice.

You can in fact get a stress fracture in any bone, though they most commonly occur in the lower limbs. The most common stress fractures for runners, as you might expect, occur in the hip, leg and foot bones. Of these the vast majority – over 80% – are found in the legs.

‘The most common running-related stress fractures are to the tibia,’ says physiotherapist Neil Smith, of Six Physio. ‘This is followed by fractures to the metatarsals [the small bones of the foot], the fibula and the femur. Stress fractures can also occur in the pelvis in runners, although this is much less common.’

When it comes to the feet, the American Academy of Orthopaedic Surgeons says the most common places for stress fractures are in the second and third metatarsals, which are thinner and often longer than the first, and therefore absorb the greatest impact when you push off. Stress fractures are also fairly common in the heel, the ankle and in the midfoot.

A sudden increase in mileage is one of the most common causes of stress fractures

What are the different causes of stress fractures?


A stress fracture is most likely to develop gradually. Any repetitive force, which of course includes the impact from running, causes microscopic damage to the bone. And if the bone is not then given enough time to recover, it can result in a stress fracture. Bones need time to adjust to increasing loading forces from running, whether that is an increased weekly load or just doing too much, too soon, without giving the body time to adapt. A sudden increase in mileage, in running more days a week, or in running for considerably longer periods of time than before are among the most common factors.

Bone density

Conditions like osteoporosis also put runners at risk of developing a stress fracture. Studies have shown that stress fractures are more common in the winter, when we have less vitamin D in our bodies. The NHS recommends that all people in the UK take a daily vitamin D supplement, and this is even more important during winter. You can also make sure your diet is rich in vitamin D sources, such as oily fish, red meat, eggs and fortified foods like breakfast cereals.

Women are also at a greater risk of developing stress fractures – particularly those with a low BMI. Irregular periods in women can also pose a risk.

Running form

Your running form is also thought to potentially impact your likelihood of developing stress fractures, at least in some cases. ‘There does seem to be a link to tibial stress fractures with those who overstride, with a definite heel strike,’ says physiotherapist Neil Smith. ‘This type of running style also increases load at the hip, increasing the possibility of femoral stress fractures.’

But before you make a sudden decision to totally rework your form and switch to a forefoot stride, consider again. ‘Running with a forefoot strike increases the load on the foot and ankle, which can increase the risk of stress fractures in the foot. Making the change to more minimal footwear or to a forefoot strike too quickly can increase the risk of a metatarsal stress fracture,’ warns Smith.

People who overpronate are also more susceptible to stress fractures, because they put a lot more medial loading force on their legs.


Poor or insufficient nutrition can also put you at risk of stress fractures. Research published in The Journal of Foot & Ankle Surgery reported that low levels of vitamin D may increase the risk, and also suggests that active individuals may need higher levels of it than the general population. As mentioned above, it is anyway officially recommended by the NHS that all people should consider supplementing their vitamin D levels, at least during the autumn and winter.

Low levels of calcium can also put runners at risk, as – potentially – can a high caffeine intaketoo much sodium in the diet and generally not eating enough to offset activity levels. This may lead to RED-S, which itself is linked with stress fractures.

Change in surface

If you’re a treadmill runner who suddenly shifts to doing all your miles on the road, or a trail runner who suddenly moves to tarmac, then this can also increase the risk of a stress fracture. Any sudden dramatic change in your running surfaces is a potential risk factor, so always try to shift gradually to allow the body to adjust.

The wrong equipment

Wearing old or incorrect (for you) running shoes that have lost their shock-absorbing abilities may contribute to stress fractures. It’s always worth having your gait analysed in a running shop – and not just when you start running. Over time, your gait or form can change so it may be worth revisiting this, particularly if you are starting to suffer from niggles that may be related to your footwear.

Poor or insufficient nutrition can also put you at risk

What are the symptoms of a stress fracture?

The most common symptoms of a stress fracture are:

  • Pain during a run that gets worse as you go
  • A sharp pain that you can pinpoint on a bony area, which may also feel tender and painful to touch
  • Pain when resting
  • Swelling on the top of the foot or on the outside of the ankle
  • Changes to your running form

A problem that comes on suddenly is always a red flag, so if you’ve had no symptoms previously but rapidly acquire a pain which is acute enough to prevent you from moving normally, it’s time to take action and get medical advice.

As discussed, runners typically get stress fractures in their feet, shins, knees and hips. Point tenderness is when a specific bone feels sore to the touch, and performing the ‘hop test’ is a good way to identify this: carefully, hop a couple of times on the injured leg. If it hurts when you land (eg, on impact), it could potentially be a stress fracture, though of course this is only a home test and a proper medical diagnosis is needed.

Swelling in the affected area is another common sign. When it comes to stress fractures in the feet, while you could see swelling anywhere, it most commonly occurs on the upper side of the foot due to a stress reaction or fracture in the metatarsals. Because of such swelling, the contour of the veins on the top of the foot may be less visible compared to the other foot.

You should also watch out also for changes in your biomechanics while running. If you’re in so much pain that you need to adjust your form, consult a medical professional right away. Not least because by changing your form or running ‘unevenly’ like this, you could cause further problems as well as the potential initial stress fracture.

Can you run with a stress fracture?

Quite simply: no. Running on a stress fracture, even if you think you can tolerate the pain, is never a good idea. It will delay healing, and could potentially make the problem even more serious, leading to a still longer break from running. It may also cause you to develop other, compensatory injuries.

Running on a stress fracture can make it much worse

How do you treat a stress fracture?

If you suspect you may have a stress fracture, the first thing you should do is stop running and rest. Any activities that are load-bearing or involve impact should also be avoided until you have received medical advice. Your GP will be able to refer you to a physio or may direct you to get an X-ray or other scan to confirm a diagnosis. If you can’t see a doctor quickly, the best idea in the short term is to apply RICE – rest, ice, compress and elevate the area – until you are seen.

Once diagnosed by a doctor, who’ll use an X-ray, CT, MRI or DEXA scan to check the injury, a splint or boot may be used to support the bone as it heals. Pain can be treated using painkillers such as paracetamol and by icing the affected area. The best way to heal is to rest the affected area as much as possible.

‘The most important treatment is rest,’ says Oliver. ‘Individuals need to have a complete rest from the activity that caused the stress fracture, and engage in a pain-free activity during the six to eight weeks it takes most stress fractures to heal.’

If running is resumed too soon, this can cause larger fractures to develop, which can lead to chronic problems in the bone. In certain rarer cases, a stress fracture will require surgery in order to heal completely. In most cases, this will involve supporting the bones by inserting a fastener, for example a pin, screw or plate.

How long does it take for a stress fracture to heal?

It can take anything from six to eight weeks for a fracture to fully heal. But just because you have a stress fracture doesn’t mean you can’t still exercise, especially if you follow a program devised specifically for you by a sports doctor or physio. You can keep your cardiovascular fitness going by cross training – low-impact activities such as cycling or swimming are usually best, but talk with your doctor to discuss what you should and shouldn’t be doing as your fracture heals. Everyone is individual so what works for one person won’t necessarily be best for you.

Having a gait analysis from an experienced physio as you begin running again can also help to pin down any biomechanical issues that could put you at risk of re-injury.

How can I avoid stress fractures in the first place?

Increase exercise slowly

‘My biggest training tip of all would be to make all changes gradually,’ says Smith. ‘Advanced planning for any training programme is a great way to prevent stress fractures. Set yourself a mini 4 to 6 week pre-training programme involving a very gradual increase in mileage.’

Oliver agrees, saying, ‘When participating in any new sports activity, set incremental goals. For example, do not immediately set out to run five miles a day; instead, gradually build up your mileage on a weekly basis.’

Always follow the 10% rule – not increasing your weekly mileage by more than 10% each week.

Visit a physio

Research suggests that treating biomechanical flaws can help prevent stress fractures. If you think you might be susceptible, visit a physio to get an assessment of your running technique. They can then ‘prescribe’ you with specific prehab exercises to correct any issues before they escalate and cause problems for you.

Vary the surface of your runs

If possible, it’s generally a good idea to do some of your weekly miles on a softer surface – such as trail, or grass, or treadmill – rather than always on concrete pavements or tarmac roads. Also always be open to substituting a planned run for some cross training – for example, instead of a ‘recovery’ or ‘easy run‘, you could do a swimming, elliptical or stationary bike session.

Eat a healthy diet

Make sure that you get enough calcium in your diet to prevent osteopenia or osteoporosis. Adult runners should aim for 1,000 milligrams of calcium per day – a good source should have at least 100 milligrams per serving. Foods such as yoghurt, milk, cheese, tofu and dark, leafy greens are all great options. If you follow a vegetarian or vegan diet, it may be worth being extra careful to include plenty of sources of iron and omega-3 fatty acids, as these are difficult to obtain when not consuming meat or fish. Vegan and plant-based runners also need to consider their vitamin B12, iodine and calcium levels.

Add strength training to your running plan

One of the best ways to prevent muscle fatigue and the loss of bone density is strength training. Use our runners guide to strength training to ensure you’re doing enough.

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