Stress Fractures (Bone Stress Injuries)

What it is

A bone stress injury is bone worn down by repetitive loading faster than it can repair. A 2022 expert primer describes a continuum from a stress reaction to a stress fracture and ultimately a complete fracture¹, so a small problem caught early is a much smaller problem.

The site decides how it is handled. A 2021 clinical review puts injuries of the shafts of the tibia and metatarsals at more than half of bone stress injuries in runners, and low risk². The pelvis, sacrum and femoral neck are high-risk sites³, so pain in the hip, groin or pelvis is seen promptly. The guide on shin splints covers the earlier stage in the shin.

Why runners get them

Load first. A 2021 review argues that every bone stress injury in runners comes from an error in workload, in which the number and size of loading cycles exceed what the bone can resist. It says there is no single optimal workload, and that in a mature skeleton a sensible progression of training, particularly intensity, lets performance rise while limiting damage⁴. Build in small steps; the guide on progressive overload covers how.

Food second. Among 183 competitive female distance runners in a 2021 study, the rate of bone stress injury was 2.25 times higher in those with infrequent or absent periods than in those with regular periods, and the authors advise avoiding menstrual disturbances and long periods of low energy availability⁵. Missed or irregular periods are a reason to see a clinician. A 2025 consensus update on the female athlete triad now includes bone stress injuries in its bone health spectrum and moves away from a single energy-availability threshold⁶, so there is no calorie number to hit; the whole picture counts.

Men are not exempt. In a 2019 study of 156 male collegiate runners followed about 1.9 years, 27% had a bone stress injury, and a risk score built from low energy availability, low body mass index, low bone density and a prior injury predicted who was hurt⁷. A past bone injury is a reason to ask a clinician about bone density and fueling, and in women a past injury at a high-risk site went with lower spine bone density³.

The first signs

Clinicians who treat women runners find the early signs come in this order. The first is effort, not pain: run after run feels like a grind, and heat does not explain it. Next comes a low-level spot that feels off at the start of a run, eases as you go and is gone afterwards. Then the pain stays through the run and shows at rest. Last, it settles after three days of rest and comes back when you start again, which is the stress fracture pattern. See someone at the first spot. In one clinic's experience, the same injury seen at the first spot costs about two weeks and seen late costs about 12.

Do not wait for a tender spot you can press. In a 2022 study of 50 people with tibial pain, focal tenderness to palpation picked up 48.6% of the stress fractures found on a bone scan and the fulcrum test 45.7%, and the authors judged even the best of five clinical tests inadequate for definitive management⁸. A normal exam does not rule a stress fracture out.

As soon as you suspect one

Stop running until a clinician has assessed it. Tenderness over the tibia is reason enough to be assessed⁹. Keep your fitness with aerobic work that adds no lower-body impact, at an easy conversational effort, which is zone 2 in a five-zone model.

See a professional promptly for pain in the hip, groin or pelvis, and for any bone pain after a change in training that is not clearly improving within a few days of reduced load. That timing is a rule of thumb, not a measured cutoff.

How it is treated

Management follows the injury's location and its risk of healing complications. The 2022 primer says injuries at low-risk sites typically heal with activity modification followed by progressive loading and return to activity, while non-weight-bearing immobilization, medication or surgery are usually kept for high-risk sites¹. A clinician sets the timeline for your site and for how the bone is healing.

For low-risk tibial and metatarsal injuries, a 2021 clinical review says the optimal load is guided by the healing process and driven by symptoms: at every stage it produces none during, after or the day following loading. It describes an initial period of reduced load, by partial or non-weight-bearing, with cross-training to keep fitness². Do not cut food while the bone heals.

Coming back

The same 2021 review describes a return-to-run program that can start once you are pain free in daily activities for 5 consecutive days, with progress directed by symptoms and volume raised before speed. Its authors call the approach clinically successful but in need of further scientific validation².

A 2024 scoping review of 50 sources on returning to running after a tibial bone stress injury found no strong evidence to guide it, since most were reviews or clinical commentaries. It lists five things to address before running resumes: resolution of bony tenderness, pain-free walking, radiological healing in high-risk injuries, strength, functional and loading tests, and the factors that contributed to the injury. It suggests starting with walk-run intervals, progressing distance ahead of speed and intensity, and sharing the decision between clinician, coach and athlete⁹. The date for your first run comes from your clinician, not from the calendar.

Fix what caused it before you build back: the load that rose too fast and any gap in fueling. The guide on returning to running covers the steps.