What Causes Bad Sitting Posture?

A common phrase among office workers is, “Sitting is the new smoking.” We all know it’s unhealthy. But what are the actual causes of poor sitting posture? We need to learn what computer posture mistakes to avoid first, before we can implement healthy habits of a sedentary lifestyle.

Causes Bad Sitting Posture - in photo: woman with bad posture using the computer
What causes bad sitting posture? Photo by Kuprevich via Megapixl

You would think our bodies are at rest when we sit. That’s true for a lot of our muscles. They are deactivated and underused when sitting at a computer. The rest of our muscles are constantly activated. This causes repetitive strain and overuse injuries to those muscles and their tendons.

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 desk worker health 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.

Benefits of Good Computer Posture
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.

What causes bad sitting posture?

This article will talk about the causes of poor sitting posture. It’ll also talk about common sitting posture mistakes, plus the health risks that come along with them.

Why is my posture so bad?

Our muscles and tendons are not designed to be constantly activated for long periods of time. As office workers, this means 8 hours a day. Over time, this repetitive strain and overuse causes health risks. Sitting with good computer posture can alleviate some of these risks, but not all of them. More importantly, poor sitting posture makes our computer-related pain much worse.

Health risks of poor sitting posture

Muscle tension

Our muscles are designed to be strong and durable. We can lift heavy things multiple times. But there’s always a limit to that durability. An old friend I’d lift weights with used to tell me, “The weight always wins in the end.” Meaning, you can try to lift as heavy as you want. And you may lift it successfully. But eventually, as you keep increasing the weight, the weight is eventually going to win.

The same goes for holding our posture in the same position at a computer desk. Even though these muscle holds are low impact and long duration, there is eventually a breaking point. The problem is, we often don’t notice it first when we’re sitting at a computer. Our muscles get tight at our office desk, which is often not painful. Then, we try to complete daily activities like sports, weightlifting, or running. That’s when we’re more susceptible to injury, because our muscles are tighter from sitting at a computer desk. After sitting at a computer for a couple years, our muscles can no longer compete (in exercise or sports) at the level we’re used to. But we still try to, which leads to chronic pain caused by computer-related muscle tension.

Chronic pain

As stated in the previous paragraph, we often don’t notice muscle tension when we’re working at a computer. And the muscle tension was rarely the spot of my chronic pain.

Muscles are connected to tendons. And tendons attach muscles to bones, usually at a major joint. This is where I’d always feel most of my computer-related pain. Muscles get tighter and shorter due to repetitive strain from poor computer posture. These shorter muscles pull harder on their tendons as time goes on. This causes overuse and inflammation of the tendons.

Tendons are meant to be durable. But they have much less blood flow than muscles. So tendons typically experience pain before muscles. Especially when it’s a low intensity, long duration muscle hold causing the computer-related injury.

To learn more, check out my article titled, Poor Computer Posture: The Cause and Effect Relationship Between Muscle Tension and Chronic Pain.

Decreased blood flow

Decreased blood flow is a dangerous effect of bad sitting posture. We basically have 2 categories of muscles when sitting at a computer. Muscles that are underused, and muscles that are overused. Both underuse and overuse (for long periods of time) can cause decreased blood flow. This means our muscles, tendons, ligaments, even our brains, share the same decreased blood flow. This affects us both physically and mentally.

Decreased range of motion

As if our tight muscles, chronic pain, and decreased blood flow weren’t enough negative effects of bad sitting posture, one of the first signs we notice is decreased range of motion. This is because our overused muscles can get tighter, shorter, and compressed. Sometimes, they get overextended and lengthened. It depends on the muscle and the angle its closest joint is held in for long periods of time. I like to refer to this as muscle confusion. Muscle confusion causes joint dysfunction, which leads to decreased range of motion.

Mental fatigue

We’re only allotted a certain amount of energy each day. This energy is divided up between our mental and physical energy. The more physical energy I would use, the less mental energy I had available to give.

It also applied to the opposite scenario. If I had a lot of mental stress on my plate, my physical energy would suffer. When that would happen, my muscles would tighten up quicker. This would cause my computer posture to suffer earlier in the day, compared to if it was a lower stress workday.

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Common sitting posture mistakes

Monitor is too low

I used to have my eye level much higher than the top of my monitor screen. This caused me to tilt my head downward to look at my monitor screen. It put my neck in an overextended, compromised position. Our necks are made to get in this position. But they aren’t meant to hold this position for long periods of time. This caused spinal disc degeneration in my neck. I learned this from x-rays my chiropractor took.

What is the correct monitor height for sitting at a computer?

I couldn’t reverse my spinal disc degeneration, but I could stop the future damage by raising my monitor height. I like to keep the top of my monitor screen even with my eye level. Also, I make sure I’m sitting with good computer posture, not slouching forward, when I raise my monitor to the correct eye level.

Elbow level is too low

I used to sit with my chair too low and my elbows below my desk level. This caused constant activation and overuse of my bicep muscles (to lift my hands up onto the keyboard and mouse). This caused short, tight biceps. The shorter my biceps got, the more they pulled on the bicep tendons that attach to bone in my elbows and shoulders. This caused chronic shoulder pain. For more info, read my article titled, Why Does Sitting at a Computer Cause Shoulder Pain?

What is the correct elbow level for sitting at a computer desk?

I fixed this computer posture mistake by raising my office chair. The correct elbow height for me is when my elbows are slightly higher than my office desk. This allows my biceps to relax, not being constantly activated for long periods of time. My forearms are at a slight downward angle, while my hands are resting on my keyboard and mouse.

Feet are not flat on the floor

Believe it or not, foot positioning at a computer definitely matters. I used to sit with my hamstrings constantly activated. This would pull my feet underneath my office chair, and under my body. My feet rested on my toes and my heels were up in the air. This caused a lot of knee dysfunction. It also led to 3 ankle surgeries for me. I sprained my ankle playing basketball. But I sprained it because of the ankle dysfunction caused by not having my feet flat on the floor (while sitting at a computer for long periods of time).

What is the correct foot position for sitting at a computer?

The correct foot position for sitting at a computer is simply having your feet flat on the floor (or a footrest). If you have to raise your chair to get the correct elbow level compared to desk level, it sometimes will raise office workers’ feet off the floor. If this happens, then a footrest would be necessary. In that case, the correct foot positioning would be flat on the footrest.

Keeping feet flat on the floor (or footrest) when sitting at a computer for long periods of time keeps the ankle in a neutral position. It also avoids repetitive strain in the muscles around the ankle.

Notice the signs of bad sitting posture in this image. The user’s elbow level is below desk level. This used to cause me chronic shoulder pain. Also, his hamstrings are constantly contracted so this pulls his feet underneath his chair. This caused me knee and ankle dysfunction. Image by Inegvin via Megapixl.
Notice the desk setup for good posture in this image. The user’s elbow level is slightly higher than desk level. His feet are flat on the floor. We want our computer desk setup to be an asset that promotes good sitting posture as soon as we sit down. This image is an example of that. Image by Inegvin via Megapixl.

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 what causes bad sitting posture, check out my book titled 45 Ways to Improve Computer Posture.

>>> Click here to learn more

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45 Ways to Improve Computer Posture by Todd Bowen

This book is a great supplement to the article you just read. It covers healthy ergonomic habits like posture, sleep, hydration, and breathing.

I wrote this book to be the resource I wish I had back in 2002, when I first started sitting at a computer for long periods of time.

Go to SittingPosture.com/book to learn more.

Take care,

Todd Bowen

To keep up with my latest desk posture tips, sign up for my Computer Posture Newsletter.

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