Running Injuries Series: Bone Stress Injuries in Distance Runners
Lately, my caseload has been filling up with women who are experiencing bone health issues, often in the form of osteoporosis. While osteoporosis primarily affects postmenopausal women, it got me thinking — what if women in their 20s, 30s, and 40s knew more about bone health earlier?
Would we see fewer stress fractures now?
Would we decrease osteoporosis risk later?
Over the next few months, I’m diving deep into bone health — specifically as it relates to distance runners. I might be slightly biased (I am a runner myself), but I also regularly treat runners dealing with bone stress injuries (BSIs) or who have had one in the past.
And here’s the thing: BSIs are incredibly common.
Research suggests that somewhere between ⅓ to ⅔ of competitive runners will experience a bone stress injury at some point. That’s a lot of runners. I can personally name several teammates from high school and college who had BSIs — and I’m sure there were plenty that went undiagnosed.
So let’s start with the basics.
What Is a Bone Stress Injury?
A bone stress injury (BSI) exists on a continuum:
Stress reaction
Stress fracture
Full bone fracture
These distinctions are typically identified on MRI and each stage requires different management strategies (which we’ll get into in future posts).
For today, we’re focusing on risk factors — but first, a little background on what’s actually happening inside the bone.
How Bone Stress Injuries Happen (The Simple Version)
When we run, our skeleton absorbs load. That load creates tiny microfractures (microtrauma) in bone tissue.
This is normal.
This is healthy.
This is how bones get stronger.
Bone is living, responsive tissue. Specialized cells — osteoclasts (which remove damaged tissue) and osteoblasts (which build new tissue) — work together to remodel and strengthen bone after loading.
Problems arise when:
The damage accumulates faster than the bone can repair
The remodeling process gets disrupted
The bone’s ability to tolerate load is compromised
That’s when a bone stress injury develops.
Risk Factors for Bone Stress Injuries in Runners
Bone stress injuries are multifactorial. They typically involve a combination of mechanical loading factors and bone health factors.
Let’s break them down.
1. Mechanical Risk Factors
These influence how load is applied to the body:
Biomechanics
Ground reaction forces (GRF)
Acceleration and shock absorption
Alignment and anthropometry
Running gait kinematics
Training Load & Programming
One of the biggest contributors to BSIs is rapid change.
Large increases in mileage
Increased running speed
Increased training frequency
Longer duration runs
Bones adapt well — but they need time. Sudden increases in workload can overwhelm the remodeling process.
Muscle Strength & Endurance
Muscle is protective, not causative.
Strong, well-conditioned muscle:
Absorbs shock
Reduces strain on bone
Improves running mechanics
However, muscle fatigue can:
Alter running kinematics
Increase load on specific bony structures
Increase injury risk
This is why strength training matters for runners.
Training Surface & Terrain
It’s less about the specific surface and more about abrupt changes in surface.
Harder surfaces may increase load
Downhill running increases stress on certain bones
Sudden terrain changes increase risk
Consistency and gradual progression are key.
Shoes & Inserts: older, worn-out shoes might contribute to increased risk — though evidence here is mixed. Shoes alone rarely cause a BSI, but they can be one piece of the puzzle.
2. The Bone’s Ability to Resist Load
The second major factor is how well your bone can tolerate stress.
This is influenced by:
Bone Mass & Structure: some aspects we can’t change, but we can influence:
Physical Activity History (particularly what type and how much PA was done through childhood/teenage years)
Energy Availability (especially for female runners!)
Low energy availability is one of the most important risk factors for bone stress injuries in women, and occurs when dietary intake does not adequately support energy expenditure.
Calcium & Vitamin D Intake
Why This Matters
If you’re a runner in your 20s, 30s, or 40s, bone health isn’t just a “later in life” concern.
The habits you build now:
Influence your risk of stress fractures
Affect long-term bone density
Impact osteoporosis risk decades down the road
Bone stress injuries aren’t random. They’re usually the result of load, recovery, nutrition, and physiology interacting over time.
And the good news?
Many risk factors are modifiable.
What’s Next in This Series?
In future posts, I’ll cover:
How to identify early signs of a bone stress injury
The role of low energy availability in runners
Return-to-run considerations
How strength training supports bone health
If you’re a runner dealing with persistent shin, foot, or hip pain — or you’ve had a stress fracture before — this series is for you.
If you’re local to Arlington Heights and looking for guidance on running injuries or bone health, I’d love to help. Bone health is something we can proactively support — not just react to after injury.
