Why Does Sitting at a Computer Cause Shoulder Pain?

When it comes to sitting posture ergonomics, back pain is the most common work-related injury. In my experience, this was definitely true. However, shoulder pain was in a close second place.

Why Does Sitting at a Computer Cause Shoulder Pain: person experiencing shoulder pain
Why Does Sitting at a Computer Cause Shoulder Pain? Photo by Andreypopov via Megapixl.

But why does sitting at a computer cause shoulder pain? It’s not like we’re doing overheard shoulder presses at our computer desk. We’re not using our arm to throw a fastball. We’re not even pushing open a heavy door. Also, we’re simply sitting at a computer, holding a keyboard and mouse for 8 hours a day.

But that’s the answer. Our bodies were made to move. They’re designed to be athletic, strong, and flexible. We weren’t made to hold the exact same position for 8 hours a day. Especially if it’s a compromised, poor posture position at a computer. This can cause repetitive stress injuries. These overuse injuries cause chronic muscle tension that is very stubborn and hard to relieve. It takes much longer to release this muscle tension. Longer than it would to relieve normal muscle tension you’d get from sports or exercise.

This article is not professional medical advice. It’s based off my personal experience and opinions. Years of my poor computer posture caused shoulder strain, muscle tension, inflammation, and pain. All the workplace ergonomic tips I write about are directly related to improving posture at a computer. Do your research. Make good decisions. And be the best advocate possible for your own healthcare.

How to Improve Computer Posture Newsletter

Why does sitting at a computer cause shoulder pain?

Elbow height is below desk level

Take a look at the below picture. The user’s chair is too low. I know this because his knees, and his elbows, are less than a 90-degree angle.

Why Does Sitting at a Computer Cause Shoulder Pain: illustration of a poor computer posture
This is an example of poor computer posture. The user has their elbow height below keyboard, mouse, and desk level. Photo by Burlesck via Megapixl.

I like to keep my knees and elbows at slightly more than a 90-degree angle. If the user would raise the chair height, he’d receive many good posture benefits immediately. We want to have a desk setup that is an asset to promote good computer posture. We don’t want our desk setup to be a liability that causes excessive muscle tension. By raising office chair height, it will bring this user’s elbow level slightly above the keyboard, mouse, and desk level. This will reduce overuse of the bicep muscles. Which will essentially reduce pain and inflammation of the shoulder tendons.

Side note: Raising office chair height would also reduce this user’s hamstring compression and quadricep overextension. To learn more, check out my article titled How to Position Feet When Sitting at a a Computer.

Okay, back to shoulder pain. Elbow height is probably the most important variable I practice to avoid shoulder pain at work. When our elbow is below the desk, we have to engage our bicep muscles in order to lift our hands and arms onto the keyboard and mouse. Even though this is only a very slight bicep contraction, it can cause a lot of neck and shoulder pain when it’s held for 8 hours a day. I like to keep my elbows at slightly more than a 90-degree angle. This will engage my tricep muscles more and take some of the burden off my biceps.

anatomy of the shoulder on how to Relieve Shoulder Pain
Notice how the biceps are directly connected to the shoulder by 2 tendons. Contracting and overusing the biceps used to be a common way for me to have shoulder pain at work. Photo by Stihii via Megapixl.

Each bicep has a tendon that connects to a bone in the front shoulder area. I usually feel pain in a joint or a tendon. I rarely feel pain in the muscle. However, that doesn’t mean the muscle isn’t the cause of the pain. When we overuse our biceps, it can handle it without giving me pain at work. But, it’s overextending the tendons connected to the shoulder. This is where I’m more likely to notice the pain. That said, keeping my elbow at slightly more than a 90-degree angle is my favorite way to prevent shoulder pain at work.

Take a look at the picture below. This is what happens when you raise your chair height. The desk setup turns into an asset that promotes good computer posture. Not a liability that creates more muscle tension.

Why Does Sitting at a Computer Cause Shoulder Pain: correct way to set chair height
When you raise your chair height to the correct position, this is what good sitting posture looks like. Photo by Burlesck via Megapixl.

Notice how the user’s knees and elbows are all slightly more than a 90-degree angle. His elbow height is also slightly above the keyboard, mouse, and desk level. This takes a lot of overuse off his biceps. Which will essentially reduce shoulder strain. You’ll also notice how the user isn’t slouching forward anymore, simply because he raised the chair height to the correct level.

3 Ways to Improve Computer Posture Immediately! ebook by Todd Bowen

Excessive internal shoulder rotation

As we place our hands and arms on a keyboard and mouse, we naturally tend to rotate our shoulders internally. Internal shoulder rotation can be a good thing when throwing a ball, lifting weights, even pushing a heavy door open. However, keeping my shoulders internally rotated for 8 hours a day is a very bad thing. It used to cause me a lot of shoulder strain and pain at work. Learning how to avoid excessive internal shoulder rotation is a key way to prevent shoulder pain. To learn about the 3 types of shoulder rotation, check out my article titled How to Avoid Shoulder Pain at a Computer.

Overextending arms and hands to reach the keyboard and mouse

I used to keep my mouse and keyboard far from the edge of my desk. This would cause me to overextend my hands and arms in order to use them. This would cause upper body pain in my back. I would start the day with my keyboard and mouse at the edge of my desk, in a comfortable position that was easy to reach. As the day went on, the stress of my day built up. Even though it was an incorrect position, it felt natural for me to extend my hands and arms forward. I would subconsciously move the keyboard and mouse forward as the day progressed.

By the time it was my lunch break, my keyboard and mouse would end up almost underneath my monitor. This would cause both neck and shoulder pain for me. To avoid overextending my arms and hands to reach the keyboard and mouse, I bring my monitor closer to me. This means that my keyboard and mouse don’t have anywhere to slide forward. This essentially keeps my keyboard and mouse within a comfortable arm’s reach at all times.


Now that we understand why sitting at a computer causes shoulder pain, we can take a more proactive approach towards healing shoulder pain and avoiding pain in the future. This article is long enough. So if you’d like to know more on how to heal shoulder pain at work, check out my article titled How to Sit at Your Desk to Relieve Shoulder Pain.


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 computer work causes shoulder strain and 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

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