Office Chairs: A Two-Part Series on What Makes Them Tick

office chair 3Office chairs are a curious thing, aren’t they?

We rely on them every day, but you rarely think about how they’re constructed until something goes wrong.

That annoying pneumatic lift breaks and you sit about a foot lower than you should. Or maybe there’s an endless string of squeaks and creaks every time you lean back or move from side to side. The old saying, “Out of sight, out of mind,” is definitely appropriate here.

Serving as an office chair in the workplace is a thankless job, and perhaps it’s in the name of these faithful pieces of furniture that we decided to learn more about how they’re built, how they work and which ones are best suited for your specific work situation.

The Pneumatic Lift: How It Keeps You Propped Up From 8-5

You can thank compressed air for the way your chair rises and falls when you reach down and adjust your seat height.

Just like drills and nail guns hooked up to an air compressor, your chair relies on highly pressurized air to alter the height of your seat.

The cylinder that connects your chair’s star-shaped wheel structure and the bottom of your seat is where most of the compressed-air magic takes place.

That cylinder is filled with the compressed air, and the lever you use to raise and lower yourself activates a piston that moves up and down in the cylinder. When you want to move your seat up and you push the lever a few times, you increase the pressure in the chamber. As that pressure increases, it forces your seat upward.

If you’re up a little too high and you want to low the chair, you move the lever in the opposite direction. In this situation, you’re easing off the piston in the cylinder, which means the air inside is less pressurized and the seat falls. Simple stuff, right?

How an Office Chair Supports Your Back

We’ve all felt the ache of sitting in our office chair after a long, 10-12-hour day at work. When you stand up, there’s that familiar tight feeling near the base of your spine and it takes about 20 or 30 seconds of walking for things to warm up and loosen. says if your goal is to keep your back comfortable, your office chair should have two important features: lumbar support and a solid backrest.

Lumbar Support

Don’t get your backrest and lumbar support confused. The backrest is the main structure you lean back on when you sit, and the lumbar support is that bump at the bottom of the backrest that supports the base of your spine when you sit down.

“An ergonomic chair should have a lumbar adjustment (both height and depth) so each user can get the proper fit to support the inward curve of the lower back,” chiropractor Rodney K. Lefler wrote for Spine Health.

If you don’t find a chair with good lumbar support, your tendency to slouch in your chair will put stress on your lower spine and flatten out structures in your back that should be curved.

Back Rest

There are two important factors here: seat width and adjustability. Your backrest should be between 12 and 19 inches in width, Spine Health says. In other words, the seat’s backrest should span the width of your back so it can provide a full support profile.

Second, the chair needs to have a way for you to adjust the angle and height of the backrest. Having this ability means you can customize your back rest to the unique angles and structures of your back. This is usually a feature you’ll find in chairs that have a separate seat and back rest.

If the seat and backrest are connected, Spine Health says, “the backrest should be adjustable in forward and back angles, with a locking mechanism to secure it from going too far backward once the user has determined the appropriate angle.”


Looking Ahead: How to Decipher Office Chair Levers and Ratings


While most of us have a pretty good sense of what our office chair needs in the way of back support, all those little levers as well as ratings given by office-supply stores can be confusing.


In our second post of this series, we’ve examined some of the popular levers and what they do, as well as unpacked chair ratings and what they mean for your particular situation.


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