Stress fracture risk

What it is

Bone constantly remodels: old bone is removed and new bone laid down. Under increased load the removal phase happens first, so bone is temporarily weaker before it is stronger. If load keeps increasing during that window, the bone accumulates damage rather than adapting.

The second half of the story is fuel. Low energy availability - not eating enough for the training being done - suppresses the hormones that build bone, and it is present in a large proportion of athletes with stress fractures. A stress fracture is therefore a signal about the whole system, not just about mileage.

What it feels like

• Localised bone pain that builds during activity and is worse afterwards
• Tender to press on a specific point rather than a diffuse area
• Progressing from pain at the end of a run to pain throughout, to pain walking
• Pain on hopping on that leg
• Sometimes night pain and localised swelling

What causes it

Most people have more than one of these at once, and they feed each other. Read the list looking for the two or three that sound like your week rather than for the one true answer — the ones that describe you are the ones worth acting on.

Load exceeding the rate of bone adaptation

Bone remodels on a timescale of weeks to months. Increasing training faster than that means damage accumulates rather than being repaired, which is the fundamental mechanism.

Low energy availability

Not eating enough for the training load suppresses reproductive and metabolic hormones and directly impairs bone formation. It is present in a large share of athletes with stress fractures and is the most important thing to ask about.

Menstrual disturbance

Irregular or absent periods in a female athlete indicates low energy availability and low oestrogen, both of which reduce bone density substantially. It is a red flag rather than a sign of being fit.

Low bone density

Whether from low energy availability, from previous eating disorder, from medication or from a medical condition, low bone density reduces the load bone can tolerate.

A sudden change in training

New surface, new shoes, new distance, new intensity, or a return after a break. Any step change in the loading pattern is a common precipitant.

Vitamin D deficiency

Associated with bone stress injuries in athletes and easily corrected. Worth checking in anyone with a stress fracture or a recurrence.

Previous stress fracture

A strong predictor of another, partly because the underlying training and fuelling patterns are usually unchanged.

Biomechanical factors

Leg length differences, high arches, restricted ankle range and gait patterns all affect where load concentrates, though they matter less than volume and fuelling.

Insufficient recovery

Consecutive hard days without recovery removes the window in which adaptation happens. It is the same mechanism as increasing volume too quickly.

Continuing to train through early symptoms

The difference between a stress reaction that settles in weeks and a fracture that takes months. Early bone pain is the warning, and it is routinely ignored.

Who tends to get it

• Runners, military recruits and dancers
• Athletes with low energy availability or irregular periods
• Anyone with a previous stress fracture
• People with low bone density from any cause
• Anyone increasing training volume or intensity sharply

What makes it worse, and what settles it

The qFIT routine for this

Ready-made routineStrength & Bone for Aging

qFIT already has this one built. It runs massage first, then stretching, then strength — the order that works on a body that is already sore — and every activity in it carries the reason it is there.

The button below opens your Checklist with this routine already selected, so instead of your whole list you land on just its Categories, Targets and Exercises, each with its checkbox, ready to tick as you work through them.

Have more than one problem? Tick yours under My Problems on My Profile and your Checklist's Routine list gains Recommended for my problems — every routine for the problems you picked, merged into one. Your picks stay private; that filter is the only thing they feed.

Get it checked if…

Focal bone tenderness with pain that worsens through activity and hurts at rest - stop loading and image; missed periods plus stress fractures means low energy availability, needs medical review

And whatever the body part: chest pain or unusual breathlessness on exertion; a fever alongside the pain; unexplained weight loss; pain that is constant and unrelated to how you move; new numbness, weakness or loss of bladder or bowel control; or one calf that is swollen, warm and painful. Any of those, stop and get assessed.

How it usually goes

Most stress fractures heal over six to twelve weeks with appropriate load reduction, and some sites - the femoral neck, the front of the tibia, the navicular - are higher risk and need specific management. The recurrence rate is high in athletes who return to the same training and fuelling pattern, which is why the energy availability question matters more than the return-to-run schedule. A stress fracture in someone not doing high volumes should prompt a bone density assessment.

Prevalence basis: Sports medicine surveillance

Others the same routine covers

These share the Strength & Bone for Aging routine, so the work is the same. If one of them also sounds like you, that is a reason to expect more from it, not less.

This is general information, not a diagnosis, and it cannot examine you. If it matches you, use it to ask better questions of a clinician rather than to replace one.