Why Does My Knee Hurt When I Run? (And What It Actually Means)

If you’re a runner in Seattle, there’s a good chance you’ve asked this question at some point: “Why does my knee hurt when I run?”

Maybe it started during a run around Green Lake. Maybe it showed up after increasing your mileage. Or maybe it’s that nagging ache that only appears going downhill or walking downstairs after a run.

Knee pain is one of the most common reasons runners seek care at Seattle Rehab Specialists. The good news is that most running-related knee pain is highly treatable when you understand what’s actually causing it.

What Type of Knee Pain Do Runners Usually Have?

Most runners experience patellofemoral pain syndrome (runner’s knee).

Common symptoms include:
• Dull, aching pain around or behind the kneecap 
• Pain during or after running 
• Pain with stairs or hills 
• Stiffness after sitting  

The key concept: the knee is often not the root problem—it’s where stress shows up.

Why Knee Pain Happens: Load vs Capacity

Load = what you ask your body to do 
Capacity = what your body can handle  

When load exceeds capacity, pain develops.

This often happens when runners:
• Increase mileage too quickly 
• Add hills or speed work 
• Return after time off  

Your knee isn’t “broken” it’s overloaded relative to its current capacity.

Why the Knee Takes the Stress

The knee sits between the hip and the foot/ankle.

If either area isn’t doing its job:
• Weak hips → poor control 
• Limited ankle mobility → poor shock absorption  

The knee compensates and takes on more load than it should.

Why It Hurts More Going Downhill or Stairs

These movements require the quadriceps to control your body weight.

This creates:
• Higher joint stress 
• Greater muscle demand  

If strength or control is lacking, pain appears quickly.

Common Mistakes Runners Make

• Resting without fixing the problem 
• Only stretching 
• Ignoring early symptoms 
• Returning too quickly  

These lead to the cycle of pain → rest → return → pain.

What Actually Works

1. Load Management 
Modify running not eliminate it  

2. Strength Training 
Focus on hips, quads, and calves  

3. Movement Control 
Improve how your body absorbs force  

4. Gradual Progression 
Allow the body to adapt over time

The Role of Running Mechanics

Small changes in:
• Cadence 
• Stride length 
• Posture  

Can significantly reduce stress on the knee and improve efficiency.

Why This Keeps Coming Back

Because most runners never improve:
• Strength 
• Capacity 
• Movement patterns  

Without addressing these, symptoms will return.

How We Treat Knee Pain at Seattle Rehab Specialists

At SRS we take a full-system approach:

• Strength testing (dynamometry) 
• Movement assessment 
• Running analysis 
• Progressive return-to-run plans  

This allows us to treat the root cause not just symptoms.

Why Physical Therapy + Running Analysis Work Best

Physical Therapy:
Builds strength and capacity  

Running Analysis:
Improves mechanics and reduces load  

Together:
Create long-term solutions and better performance

When Should You Get Help?

• Pain lasting more than 1–2 weeks 
• Pain that changes your running 
• Recurring symptoms 
• Difficulty progressing training

Final Thoughts

Knee pain while running is common but not something you have to live with.

When addressed correctly, runners return:
• Stronger 
• More efficient 
• More resilient

Get Help from Seattle Rehab Specialists

If knee pain is limiting your running, our team at Seattle Rehab Specialists can help.

We combine:
• Physical therapy 
• Strength testing 
• Running analysis  

To help you understand your body and build a plan to stay active long-term.

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