Is Your Winter “Base Mile” Training Masking a Stress Fracture or Bone Stress Injury?

Is Your Winter “Base Mile” Training Masking a Stress Fracture or Bone Stress Injury?

January. New shoes. Big plans. Bigger mileage – Bone Stress Injury .

For many runners, January isn’t just the start of a new year; it’s the start of Marathon Season.

With the London and Brighton marathons looming in April, the ‘base mile’ phase is in full swing. The goal is simple; build an aerobic engine by stacking up the miles.

But unfortunately, for some runners the excitement of a new training block, combined with the unique physiological challenges of a British winter can hides the early warning signs of a Bone Stress Injury (BSI), more commonly known as a stress fracture.

At Wandsworth Physiotherapy, we see a familiar pattern every winter – runners who believe they have a “achy foot”, “grumpy shin”, or “hip niggle that will settle”â€Ļ when in fact, they’re running straight through the early stages of a bone stress injury.

This blog isn’t about panic or stopping training unnecessarily. It’s about knowing when your body is adapting, and when it’s quietly waving a red flag.

bone stress injury

Why Winter Running Is Harder on Your Bones Than You Think for Bone Stress Injury

Bone is a living tissue. It remodels constantly in response to load; a process known as Wolff’s Law. In simple terms: the right amount of impact makes bone stronger. Too much, too soon? That’s where problems start.

Winter changes the equation in several ways:

Harder, Less Forgiving Surfaces

Frozen pavements, compacted paths, and cambered roads increase ground reaction forces. Unlike summer trails or grass, these surfaces don’t absorb much shock, instead, your bones do!

Mileage Goes Up, Intensity Sneaks In

“Easy miles” often aren’t as easy as we think. Fatigue alters running mechanics, subtly increasing load through the tibia, metatarsals, femoral neck, and pelvis.

Vitamin D Takes a Hit

During UK winters, sunlight exposure drops dramatically, and with it, Vitamin D synthesis, which is essential for calcium absorption and bone health. Studies consistently show high rates of Vitamin D insufficiency in endurance athletes during winter months.

Strength Training Gets Forgotten

Shorter days, busier schedules, and more running often means that runners skip their resistance training sessions – removing a key protective factor for bone density.

Bone stress injury in runners

Bone Stress Injury: Stress Reaction vs Stress Fracture: The Spectrum Many Runners Miss

Bone stress injuries sit on a continuum, not a switch.

  • Stress reaction: Bone is overloaded but not cracked
  • Stress fracture: Micro-cracks develop
  • Complete fracture: Structural failure (thankfully rare in runners)

The problem? Pain doesn’t always escalate linearly.

Many runners can train through early stress injuries, especially during base mileage, often masking the seriousness of what’s happening underneath.

Common Stress Fractures in Runners (And Why They Matter)

Not all stress fractures are created equal.

Low-Risk Sites

These usually heal well with appropriate load management:

  • Tibial shaft
  • Metatarsals (2nd–4th most common)
  • Fibula
  • Calcaneus

High-Risk Sites

These require early diagnosis and specialist input:

  • Femoral neck
  • Anterior tibial cortex
  • Navicular
  • Pelvis / sacrum

At Wandsworth Physiotherapy, we make sure that we identify where your pain sits, anatomically and biomechanically, so that we can manage your injury properly.

Some injuries tolerate modified loading; others absolutely don’t, and need to be completely offloaded.

Symptoms That Should Make You Pause (Not Push Through)

Stress fractures rarely arrive with fireworks. Instead, they grumble for a few weeks:

  • Pain that starts later in a run, then gradually appears earlier
  • Localised, pinpoint tenderness over bone
  • Pain that persists after running or lingers the next morning
  • Reduced performance despite consistent training
  • Pain that worsens on hard surfaces but eases on grass or treadmill

A key giveaway? Bone pain is often very specific – you can point to it with one finger.

RED-S – When Training Load Outpaces Recovery

Relative Energy Deficiency in Sport (RED-S) is increasingly recognised as a major risk factor for bone stress injuries, in both female and male runners.

RED-S occurs when energy intake doesn’t meet training demands, affecting:

  • Bone density
  • Hormonal health
  • Recovery and immunity

Warning signs include:

  • Recurrent injuries
  • Fatigue and poor performance
  • Menstrual irregularities (in women)
  • Low libido or low testosterone (in men)

Bone doesn’t just respond to load, it responds to availability of fuel. Without it, even sensible training can tip into Bone Stress Injury.

At Wandsworth Physiotherapy we have a sports nutrition service, to ensure that you are fuelling properly to meet your training needs.

Diagnosis – Why Guessing Is a Dangerous Game

X-rays are often normal in early bone stress injury. MRI remains the gold standard, in order to grade the severity of the injury and guide safe return-to-run decisions.

If you require an MRI scan, we can refer you to an orthopaedic or sports medicine specialist – we work closely, with some of the best consultants in London, and will ensure you are well looked after throughout your rehab journey

At Wandsworth Physiotherapy, we don’t just look at scans, we also assess:

Because stress fractures are rarely “bad luck”. They’re usually predictable, and preventable.

Treatment for Bone Stress Injury – More Than Just “Rest”

Successful recovery isn’t about stopping everything. It’s about strategic unloading and i reloading.

Your rehab may include:

  • Load modification (not blanket rest)
  • Cross-training to maintain fitness
  • Strength training to improve bone stimulus
  • Gait and footwear assessment
  • Running biomechanics assessment
  • Gradual return-to-run programming

Most importantly, we help runners return stronger than before, not just symptom-free.

Why Runners Choose Wandsworth Physiotherapy

We specialise in runners, from first-time marathoners to seasoned ultra athletes. What sets us apart?

  • Expert MSK diagnosis – no guesswork
  • Running-specific rehab built around your goals
  • Bone health-ed approach, not just pain management
  • Data driven rehab – using equipment such as force decks and muscle dynamometry
  • Close links with imaging clinics, orthopaedic and sports medicine consultants
  • Clear, confident guidance on when to train, and when not to train

We don’t just get you back running. We reduce the chance of this happening again.

If your “niggle” isn’t behaving like normal muscle soreness, Wandsworth Physiotherapy is here to help – before a small problem becomes a season-ending one.

5 Common Questions Runners Ask for Bone Stress Injury

1. Can I run through a stress fracture or bone stress injury ?
Running through pain may be possible early on — but it significantly increases injury severity and time off.

2. Are treadmills safer than roads in winter?
Often yes — treadmills reduce impact variability and surface hardness.

3. Do cushioned shoes prevent stress fractures or bone stress injury ?
Not alone. Strength, mechanics, load management, and nutrition matter more.

4. How long does a stress fracture take to heal?
Anywhere from 6–12+ weeks depending on location and severity.

5. Should all runners supplement Vitamin D in winter?
Many UK runners benefit — but testing and medical advice are recommended.

References

Bennell, K.L. et al. (1996) Risk factors for stress fractures in track and field athletes. American Journal of Sports Medicine, 24(6), pp.810–818.

Nattiv, A. et al. (2013) Stress fracture risk factors, incidence, and distribution: a systematic review. British Journal of Sports Medicine, 47(4), pp.172–176.

Tenforde, A.S. et al. (2016) Association of the Female Athlete Triad risk assessment stratification with bone stress injuries. American Journal of Sports Medicine, 44(2), pp.393–401.

Heaney, R.P. (2003) Vitamin D and calcium interactions: functional outcomes. American Journal of Clinical Nutrition, 88(2), pp.541S–544S.

Mountjoy, M. et al. (2018) IOC consensus statement on RED-S. British Journal of Sports Medicine, 52(11), pp.687–697.