Why Does Sitting Cause Knee Pain?

You would think sitting gives your legs a break. You’re not using your leg muscles to walk, or even stand. But if you aren’t using your legs while sitting, why is knee pain such a common computer-related injury?

Sitting Posture blog shares why does sitting cause knee pain - in photo: person holding his one knee in pain
Why does sitting cause knee pain? Photo by Chernetskaya via Megapixl.

This article will explain how a sedentary lifestyle caused knee problems in both of my legs.

When sitting for long periods of time, our knees are often at a 90 degree angle or less. Our knee is designed to get in this position, but it’s not designed to stay in this position. For example, jumping and squatting are other positions where it’s helpful to get our knees at a 90 degree angle.

But when our knees are at this same angle for long periods of time, that’s when it becomes a problem. It doesn’t matter that we’re sitting in a chair, it can still be causing knee pain. When we sit, the hamstring muscles on the back of our legs are activated, overused, and shortened. The quadricep muscles on the front of our legs are stretched, underused, and lengthened. These 2 muscle groups are supposed to work together evenly. Instead, the hamstrings are constantly contracted when we’re sitting, while the quadriceps are doing the exact opposite. And the more we pull our feet under our desk chair, the more destructive this position becomes.

This article is not professional medical advice. It’s based off my personal experience and opinions. For years, my poor computer posture caused muscle tension, inflammation, and chronic pain. Bad posture also decreased my mental clarity, energy level, and work productivity.

All the office wellness tips I write about are directly related to improving posture at a computer. We are our own primary caretakers. Do your research. Make good decisions. And be the best advocate possible for your own healthcare.

My ebook “3 Ways” is always free. It talks about the 3 most painful, poor posture mistakes I used to make while sitting at a computer for long periods of time. Then, it tells you how to fix those posture mistakes, immediately! You can download my ebook here.

Why does sitting cause knee pain?

I mentioned earlier how holding my knees at a 90 degree angle (or less) while sitting was one of my biggest knee pain causes. To make matters even worse, I would pull my feet underneath my desk chair. This was caused by a couple different computer posture mistakes. One of them, my chair was too low. The other variable, I worked high-stress jobs that I hated. This stress would cause my whole body to tense up. In this case, my hamstrings would contract even more. This would naturally pull my feet underneath my chair. When my hamstrings were hyper-contracted for long periods of time, they got shorter and tighter. Each of these 3 hamstring muscles was pulling on a different tendon located on the sides of the knee. A tight muscle puts pressure on its tendons. This caused pain, inflammation, and dysfunction in both of my knees.

The most confusing thing about my desk job knee pain, it wasn’t caused in my knees. My knees were just the area where the effect of different computer posture mistakes lived. My knee wasn’t the cause of the problem. I’d go to doctors who wanted to give me painkillers. I’d go to physical therapists who were solely focused on my knee. But that wasn’t the cause of the pain. The cause was located in the muscles. To learn more about the general cause of computer-related injuries, check out my article titled, Poor Computer Posture: The Cause and Effect Relationship Between Muscle Tension and Chronic Pain. That article is not strictly about knee pain, while the remainder of this article is.

What is the term for knee pain from sitting too long?

Now that we’ve learned knee pain and dysfunction often starts in the hamstring, what is the actual term for the pain that’s in the knee? Here are 2 common possibilities.

Tendonitis vs tendinosis
tendonitis

It is short-term pain in a tendon. The pain is caused by inflammation. This inflammation is usually caused by overuse of the muscle that’s directly connected to that tendon. Muscles are connected to tendons. Tendons are then connected to bone on the other end. When a muscle is overused, it pulls on the tendon. Once the tendon gets too overloaded, it gets inflamed.

Many people try to treat the tendon at the knee when it hurts. This can help decrease the pain, but this knee pain relief is temporary. It’s not getting to the root cause of the posture mistake. Which in my case, was caused by the overused hamstrings. Tight hamstrings are one of the most overlooked computer-related injuries. This is mainly because our hamstrings probably don’t hurt. We don’t even know they’re tight. But they’re having a large impact on our knee discomfort after prolonged sitting.

Tendinosis

Tendinosis is similar to tendonitis. It’s pain in a tendon that’s caused by overuse and inflammation. The difference with tendinosis is that it’s a more chronic, long-term pain. Another difference of tendinosis is the collagen in said tendon is starting to degenerate. Tendinosis is a more progressed, more extreme injury than tendonitis. And the longer I had knee pain, the harder it was to relieve my knee discomfort after prolonged sitting.

How to Improve Computer Posture Newsletter

Sitting posture and knee pain

Sitting Posture blog shares why does sitting cause knee pain - in photo: illustration of a person using the computer and sitting on his office chair with poor posture
Notice how this user has his feet pulled under his office chair. I used to sit in this exact poor posture. His hamstrings are constantly contracted and overused. This causes his knees to be bent at less than a 90 degree angle. Prolonged sitting in this position can lead to pain, inflammation, and dysfunction of the knees. Image by Inegvin via Megapixl.
Sitting Posture blog shares why does sitting cause knee pain - in photo: illustration of a person using the computer and sitting on his office chair with good posture
This image is a great example of how to prevent knee pain when sitting. His feet are not pulled underneath his desk chair, so his hamstrings have minimal contraction right now. His ankles are either directly below, or slightly ahead of his knees. Working in this good computer posture may not prevent all knee pain from sitting too long, but it has definitely reduced the risk for me. Image by Inegvin via Megapixl.

How to prevent knee pain when sitting

Keeping the knees at a 90 degree angle, or slightly more, is a great start to relieving knee pain from sitting. But there are more ergonomics variables involved. If you’d like to learn more ways, check out my article titled How to Prevent Knee Pain When Sitting.


THANKS FOR YOUR INTEREST IN COMPUTER POSTURE. 

If you’ve read this far, congratulations! You’re taking valuable steps to reduce computer-related injuries by improving your posture. That’s something to be very proud of!

If you liked this article on why sitting causes knee pain, check out my free ebook titled 3 Ways to Improve Computer Posture Immediately!

>>> Click here to download your free copy

3 Ways to Improve Computer Posture Immediately! by Todd Bowen

This ebook is a great supplement to the article you just read. In this ebook, you’ll learn 3 of the most painful, poor computer posture mistakes. Then, you’ll learn how to fix those mistakes immediately with 3 simple changes to your ergonomic computer desk setup.

Go to SittingPosture.com/ebook to learn more.

Take care,

Todd Bowen

How to Improve Computer Posture Newsletter

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.