Stress Fractures

Not quite. A stress fracture is a small crack in bone caused by repeated loading that outpaces the bone's ability to repair and rebuild itself (remodel). An acute fracture comes from a single high-force event. Stress fractures usually do not shift out of place, and often heal with protected loading rather than casting or surgery. The caveat is that some high-risk sites behave more unpredictably and need orthopaedic review early: the neck of the thigh bone at the hip (femoral neck), the front of the shin bone (anterior tibia), the navicular in the midfoot, and the base of the fifth toe's long bone (proximal fifth metatarsal).

Many low-risk stress fractures, such as the inner back edge of the shin bone, the fibula, or the shaft of a long foot bone (metatarsal), settle over roughly 6 to 8 weeks of protected loading, with a graduated return to running over the following 4 to 8 weeks. High-risk sites often need longer periods of offloading and formal medical review. Healing timelines also depend on age, nutrition, hormonal health, and whether the original training load and any underlying drivers are addressed.

Running through a stress fracture usually makes it worse. Pain that is focal over bone, worsens through a run, and lingers afterward is a signal to stop running and get it assessed. Once diagnosed, the general approach is to offload enough that daily walking is pain-free, maintain fitness with non-impact work like cycling or pool running, and rebuild running volume gradually once bony tenderness resolves.

The dominant cause is a mismatch between training load and recovery. Rapid increases in weekly mileage, sudden additions of hills or speed work, changes in surface or footwear, and inadequate recovery between sessions all concentrate load on bone faster than it can adapt. Not eating enough for the training you do (low energy availability), menstrual irregularity, low bone mineral density, and low vitamin D or calcium status add to the risk. Relative Energy Deficiency in Sport (REDs), described in the 2023 IOC consensus statement (Mountjoy and colleagues), is a recognised driver in endurance athletes and in sports judged partly on appearance (aesthetic sports).

MRI is the most sensitive scan for bone stress injury and shows fluid inside the bone (marrow oedema) before any crack appears in the bone's hard outer layer (the cortex). Plain X-rays often look normal for the first two to three weeks and can still be normal even with a confirmed stress fracture. When the clinical picture is clear and the site is low-risk, treatment can start without imaging. When a high-risk site is suspected, or recovery is stalling, MRI is worth pursuing. When imaging would change the plan, I flag it to your family doctor or specialist and refer you.

High-risk sites are places where the fracture sits on the side of the bone that is pulled apart under load (the tension side), or in an area with a poorer blood supply, so the risk of the bone not healing (non-union), shifting out of place (displacement), or breaking completely is higher. The neck of the thigh bone at the hip (femoral neck), the front of the shin bone (anterior tibial cortex), the navicular in the midfoot, and the base of the fifth metatarsal are the classic examples. These need prompt orthopaedic involvement rather than conservative rehab alone.

If your intake is low, correcting calcium and vitamin D is reasonable and often recommended. The bigger question is total energy availability. In endurance and aesthetic sports, undereating relative to training volume quietly undermines bone health, menstrual function, and tissue repair. A conversation with your physician or a sports dietitian to review blood tests, intake, and training is often more useful than supplements alone.

Return to running is part of the rehab, not the finish line. Recurrences often trace back to returning to previous mileage too fast or not addressing what caused the first one. I work with you on a graded return, usually starting with walk-run intervals once pain-free on daily walks, limiting weekly increases, adding strength work for the relevant area, and reviewing how training is planned across the season (periodisation), footwear, nutrition, and sleep. For athletes with repeated stress injuries, screening for bone health and energy availability is important.