Bone Stress Injuries in Athletes: Causes, Symptoms, and How to Prevent Them

Bone Stress Injuries

Bone stress injuries (BSIs) are overuse injuries caused by repetitive mechanical loading without adequate recovery. They often occur in the lead-up to competition and can progress to fractures, which are highly debilitating.

Bone Remodeling and Symptom Onset

Bones undergo continuous remodeling in response to microdamage. During this process, bone temporarily weakens before rebuilding, which explains why BSIs often take 3–4 weeks to show symptoms. Gradual increases in training load may delay symptom onset in athletes.

High-Risk Athletes

BSIs are common in endurance athletes, especially long-distance runners and cross-country athletes, due to repetitive high-impact loading.

Energy Deficiency and RED-S

Relative Energy Deficiency in Sport (RED-S) and the female athlete triad significantly increase BSI risk by up to 15 times. These conditions reduce bone mineral density and impair bone remodeling.

Key risk factors:

• Lean or aesthetic-focused sports

• Low bone density

• 12 hours of exercise per week

• BMI < 21

• Menstrual irregularities

• Restrictive eating

If RED-S is suspected, consult a doctor or dietitian. Adequate calcium and vitamin D intake is essential for bone health.

Sport Specialisation vs Sampling

Early sport specialisation increases overuse injury risk in junior athletes by up to 81%. Delaying this until high school is recommended. Sport sampling (playing a variation of sports) promotes balanced movement patterns and reduces injury risk during growth and development. 

Periodisation and Bone Adaptation

Planned recovery periods (periodisation) enhance bone adaptation more effectively than continuous loading. Puberty is a critical window for building bone strength — weight-bearing activity during this time leads to greater gains in bone density.

Building a Strong Skeleton

Bone size is fixed, but bone mass can be increased. High-impact, low-repetition movements stimulate bone growth and avoid desensitisation. These can be performed multiple times daily with ~4 hours between sessions. Multidirectional and novel loading (e.g. varied sports) with rest between sessions maximises adaptation.

Recognising Symptoms

Early BSI pain is vague and may not appear during activity. As the injury progresses, pain becomes sharp, localised, and movement-provoked — indicating structural bone involvement. Constant or night pain may suggest inflammation. Pain that doesn’t ease with warm-up is a red flag.

Common Triggers

BSIs often follow changes in training or environment within the past 1–2 months:

• Increased training volume or intensity

• New training types

• Equipment changes (e.g. footwear)

• Surface changes (e.g. road to trail)

Clinical Signs and Diagnosis

• Localised tenderness

• Pain reproduced by hopping or jumping

• High risk sites: femoral neck, tibia, talus, medial malleolus, navicular, metatarsals, sesamoids

• MRI is the preferred imaging modality for diagnosis; X-ray and CT may also be used

Load Management and Prevention

Managing training load is crucial. Pre-season is a high-risk period, so maintaining bone loading during the offseason (e.g. hopping drills) is recommended. Increase training volume before intensity, as intensity spikes raise BSI risk more sharply. When adding intensity, reduce volume to balance total load.

Biomechanical Factors

Running mechanics such as foot strike and cadence influence bone loading and affect BSI risk. Speak to us if you have a concern for a bone stress injury or are interested in their prevention.