Why Your Knee Hurts When You Squat, Run, or Go Down Stairs
- Dr. Andrew Frost
- Mar 17
- 4 min read
Updated: Mar 18
(And What It Actually Means)
If you’ve ever felt knee pain during a workout, on a run, or just walking down the stairs, you’re not alone.
It usually starts subtly.
A little discomfort during squats.
A tweak on a run.
An ache going downstairs that wasn’t there before.
So what do most people do?
They stretch their quads. Maybe rest for a few days. Or avoid the movements altogether. And sometimes that helps… temporarily. But then the pain comes back.
Here’s the truth:
Your knee is often not the problem. It’s the victim.
Why Knee Pain Is So Common
Your knee sits between two joints that are supposed to move a lot:
Your hips
Your ankles
Your knee, on the other hand, is primarily a hinge joint. It’s designed to bend and straighten—not absorb rotational stress or compensate for stiffness elsewhere.
So when:
your ankles don’t move well
your hips are stiff or weak
or your body can’t control movement under load
👉 the stress has to go somewhere.
And most of the time… it goes to your knee.
This is why so many people experience knee pain during everyday movements like squatting, running, and going downstairs.
The 3 Most Common Knee Pain Patterns
Let’s break this down into the exact situations most people notice pain.
1. Knee Pain When Squatting
If your knee hurts during squats, lunges, or workouts, it’s rarely just a “bad knee.”
More often, it’s a movement problem.
The most common culprits:
Limited ankle dorsiflexion (your knee can’t move forward properly)
Poor hip control (your knee collapses inward)
Overloading the patellar tendon
When your ankle doesn’t allow enough forward movement, your body compensates by shifting stress into the knee.
2. Knee Pain When Running
Runners often feel pain:
around or behind the kneecap
during or after runs
especially with increased mileage
This is commonly referred to as runner’s knee (patellofemoral pain).
But here’s the mistake most runners make:
They assume it’s a knee issue.
In reality, it’s often caused by:
poor hip stability
lack of control during foot strike
training load increasing faster than your body can handle
If your hips aren’t doing their job, your knee ends up absorbing more force than it should—step after step. Over time, that adds up.
3. Knee Pain Going Down Stairs
This is one of the biggest red flags.
If your knee hurts going down stairs (but not up), it usually points to:
poor eccentric control (your ability to absorb force)
weakness in the quads or hips
irritation around the kneecap
Going downstairs requires your body to control your weight—not just move it.
If you don’t have that control, your knee takes on more stress than it’s built for.
The Hidden Cause Most People Miss
Here’s where things start to click for most people.
Knee pain is usually a downstream problem.
The real issue is often:
something not moving enough (mobility problem)
or something not controlling movement well (stability problem)
Most commonly:
stiff ankles
restricted hips
poor coordination under load
This is exactly why stretching your knee or resting doesn’t fully solve the issue. You’re treating the symptom—not the cause.
What Actually Helps Knee Pain (Long-Term)
If you want knee pain to stay gone, you need to address the root cause.
That usually means a combination of:
1. Restoring Ankle Mobility
If your knee can’t travel forward, everything upstream changes.
2. Improving Hip Function
Your hips control where your knee goes.
If they aren’t doing their job, your knee pays for it.
3. Building Strength Through Full Range
Strength only works if you can access the positions.
That’s why mobility + strength go hand in hand.
4. Gradually Reloading the Knee
Avoiding movement doesn’t fix the problem.
You need to rebuild your capacity—strategically.
Why Your Knee Pain Keeps Coming Back
If you’ve tried:
stretching
foam rolling
resting
random exercises from Instagram
…and your knee pain still comes back…
It’s not because your body is broken.
It’s because you haven’t addressed the actual limitation yet.
Most programs skip:
proper assessment
identifying mobility restrictions
understanding how your body moves
And that’s the difference between temporary relief and real results.
What To Do Next
If you’re dealing with knee pain during:
squats
running
workouts
or even daily activities
The first step is figuring out what your body is missing.
That’s exactly why I put together a free guide.
Download Your Free 3 Step Guide To Knee Pain
If you want a clear plan to start fixing your knee pain, this is for you.
Inside the guide, you’ll learn:
The most common root causes of knee pain
Simple tests to identify your limitations
Mobility exercises to reduce stress on your knees
How to start rebuilding strength the right way
Final Thought
Knee pain doesn’t mean you need to stop training. It means your body is asking for something different.
When you improve how your body moves, you reduce stress on your knee—and get back to doing what you enjoy.
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