London Marathon 2026: A Complete Guide to Bone Stress Injuries in Runners

With the London Marathon 2026 training cycle now building momentum, this is the period when we commonly see bone stress injuries emerging in runners across Earlsfield, Wandsworth and SW18.

Understanding the early signs can be the difference between finishing the race — or missing the season entirely.

What Is a Bone Stress Injury?

Bone stress injuries (BSIs) occur when repeated impact loading exceeds the bone’s ability to remodel and recover. They sit on a spectrum:

1. Stress reaction (early overload)

2. Stress fracture (structural crack)

During marathon training, runners may take 30,000–50,000 steps per long run. If recovery, nutrition and strength capacity don’t match the load, bone tissue begins to fail.

Common Locations in Marathon Runners

Tibia (shin) – the most common site

Metatarsals (forefoot) – pain during push-off

Calcaneus (heel) – deep heel ache

Femoral neck – deep groin pain (higher-risk and needs urgent assessment)

Early Warning Signs

Bone stress injuries rarely start dramatically. They build gradually.

Watch for:

• Localised pain (you can pinpoint it precisely)

• Pain that appears earlier in each run

• Pain on single-leg hopping

• Pain that persists after the run

• Pain that begins to hurt during walking

• Night pain (more concerning)

If pain is broad and diffuse, it may be shin splints. If it is sharp and focal, think bone.

Why They Increase During Marathon Training

Several risk factors stack up during London Marathon preparation:

1. Rapid Mileage Progression

Jumping from 15km to 25km long runs within weeks.

2. Hard Winter Surfaces

More pavement running, less terrain variation.

3. Inadequate Recovery

Busy professional schedules often compromise sleep and fuelling.

4. Low Energy Availability

Under-fuelling reduces bone turnover and resilience. This is particularly relevant in endurance athletes and female runners, but affects men too.

5. Lack of Strength Training

Bone responds to heavy load and varied force. Many marathon runners accumulate mileage but neglect progressive strength work.

Prevention: What Actually Works

Evidence supports:

• Gradual mileage increases (avoid >10% weekly spikes)

• Heavy calf raises (straight and bent knee)

• Split squats and single-leg strength

• Progressive plyometrics

• Adequate carbohydrate intake around training

• Sleep >7 hours per night

Bone health is influenced by both load and energy availability.

When to Stop Running

You should stop and seek assessment if:

• Pain is focal and worsening

• Walking becomes painful

• Hopping is painful

• Pain is deep in the groin

Continuing to train through a stress reaction often progresses it into a full stress fracture.

How We Help at Back to Back Osteopaths (SW18)

For runners in Earlsfield and Wandsworth training for London 2026, we assess:

• Load management and weekly mileage

• Strength capacity vs training demand

• Running mechanics

• Recovery strategies

• Nutrition risk factors

Early intervention often means modifying training rather than stopping completely.

If you are preparing for London 2026 and experiencing persistent, localised pain — don’t ignore it.

A small problem in February can become a season-ending injury by April.

By James Dodd BSc (hons) Ost. FAFS.

GOsC registered

Bone Stress Injury

A bone stress injury (BSI) is due to a bone’s inability to cope with repetitive mechanical loading.

This results in structural fatigue with localised bone pain and tenderness.

Essentially, BSI is an overuse injury and is normally multifactorial with a combination of biological, biomechanics and anatomical risk factors.

Lower limb stress factors are much more common than upper limb stress factors. Tibial stress fractures account for approximately half of all stress fractures, followed by the forefoot and then femoral shaft and neck.

It can be broken down into extrinsic and intrinsic factors:

Extrinsic factors:

Training errors

• Excessive volume

• Excessive intensity

• Sudden change in intensity

• Poor recovery

• Excessive fatigue

Surface

• Hard/soft/cambered

Shoes

• Poor shoes/worn shoes

Equipment

• Inappropriate kit

Poor nutrition

Psychological factors

Environmental conditions

Intrinsic factors:

Training errors

• Pes planus/cavus

• Hip anteversion

• Leg length

• Muscle weakness/imbalance

• Lack of flexibility

Genetic factors

Endocrine factors

Metabolic factors

• RED’s

Previous bone stress

Smoking

Family history

The management of BSI begins with off-loading the affected bone to reduce pain and assist healing. A holistic overview is taken to improve general wellness including sleep and nutrition. This is complemented with a gradual loading programme with physical therapy.

Rapid and clear diagnosis is essential in preventing the propagation of the fracture.

To assess the history of the BSI we will need to know:

• The type of impact sport/physical activity you’ve been doing

• Any changes in intensity, frequency, time, environment

• Changes in the recovery

• Any female REDs (relative energy deficiency)

• Your general nutrition

• Where the pain is, especially when loading, e.g. for a lower limb we’d look at where the pain is when running or hopping

The point you feel the pain will help decipher how long you have been suffering with that stress fracture. Early stress fractures often give pain towards the end of an activity, whereas with more well established BSI, pain comes on earlier on, or even at rest. It can also be more intense and linger for longer in more established BSI.

Examination

To examine a BSI we would look at a number of things, focal tenderness and swelling on palpation, percussion may reproduce the pain. We would look to run a tuning fork test and a fulcrum test. For lower limbs we’d look to see if you can stand on one leg and see if you can hop on the affected leg.

Imaging

Often an x-ray will suffice to view a stress fracture, although it can take 2-4 weeks for it to show on x-ray and sometimes cannot be seen at all. If it cannot be seen we can use a bone scan - the downsides of this is they are time-consuming and involve an injection and exposure to radiation. An MRI is sensitive and specific for BSI, it gives a very accurate correlation to the picture. It can be costly though.

Management for BSI

• Offload/stop participating in activity, especially high impact exercise

• Maintain fitness levels through cross training - swimming, cycling, pool running

• Consider immobilising your injury - e.g. using a brace

• See an Osteopath who can work with you to gradually strengthen and improve flexibility

• Address any dietary needs

• Ca and Vitamin D supplements will help improve any bone issues and deficiencies

• Look at hormonal balance for those who may suffer from a hormonal dysfunction

• Address REDs if necessary

If you are concerned about an injury, BSI or other, please give us a call today on 020 8605 2323.

Blog post by James Dodd