That lever on the bottom of your adjustable task chair at your desk? Despite what your childish intuitions will tell you, it's not just for pranks. Take a moment to step away from your chair and make this one easy adjustment to improve your workspace ergonomics.
According to the American Chiropractic Association, giving your chair the proper height adjustment can spare you from a load of problems. A chair that's too low can cause lower-back pain, carpal-tunnel syndrome and rotator-cuff strain in the shoulder. A chair that's too high can lead to what's called Golfer's Elbow—pain and inflammation on the inner side of the elbow.
So if you're going to do just one thing to imrpove your office chair ergnomics, make it a height adjustment. It's as easy as standing up.
As you stand in front of your chair, adjust the height so the highest point of the seat (when in the horizontal position) is just below the knee cap. When you sit down, your feet should be flat on the floor, with your knees at a 90° angle, the ideal lower body position for sitting down at a desk.

Adjusting your chair height is also a great way to check up on the ergonomics of the rest of your workstation.
If you can't fit your legs under the desktop (you should have enough room to comfortably cross your legs at the knees) or there is not enough space to move them freely, your desk is too low for you. Put it on risers, or invest in a desk that's the proper height.
If you can sit comfortably but you have to raise your arms to reach the keyboard or work surface, your workstation is too high. Find a way to lower your worksurface (a keyboard tray might help). Alternatively, you can adjust the chair height so your elbows are the same height as your desk and use a footrest high enough so you can lay your feet flat.
(Images: Shutterstock, Taryn Fiol)

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This is all well and good for normal persons of normal height. If I adjust my chair to the "proper" height, the desk is too tall and my have to scrunch up my shoulders to type. And adjusting the height of my desk at work is not an option. Nothing is designed with shorter people in mind.
theonlynikki
adjust your chair to the height that allows appropriate reach to your keyboard and use a footrest, or get a keyboard tray that is height adjustable mounted to the underside of your worksurface.
Does the "feet flat on the floor" rule still apply when you wear pumps every day to work?
A footrest is key to comfort, in my experience.
I use an exercise ball. I love it!
FYI, typo in 3rd paragraph. ImpPRove.
Nothing is designed with taller people in mind either - this is why I had to crawl under my desk and unscrew the keyboard tray, because I can't fit under my desk with it on. Also why my sleeves are too short, button-up shirts often stop buttoning above my navel, and why I have difficulty seeing traffic lights from my car unless I slouch. The only time I can see my head in the mirror of a public washroom is when I'm standing in the stall. Things are designed for "average" users - while that shifts in one direction or another from time to time, us outliers will always be screwed. I'm also "plus-sized", wide of foot, and have a 24 3/8" head. I just expect that nothing will be adjusted for my needs, and go from there.
Meanwhile, I am going to see if this chair is correctly adjusted...I suspect it's a bit too low.
Women may need to re-adjust daily depending on your heel height.
Anyone in the shorter range who doesnt have an adjustable height desk OR adjustable height keyboard tray may need a footrest. It's not just about the height of the seat of your chair but also the height of your keyboard, the reach to your keyboard, the height of your monitor etc...
http://www.ergonomics-info.com/ergonomic-pictures.html
Hi everyone. I recently bought a standing craft table and I love it! But I'm trying to purchase the perfect chair and I don't know what height size to look for.
The craft table is about 37 in high. I want a comfortable drafting chair and I've never purchased one so I don't know what is the perfect height.
Help please!
When you are seated, your knees should be squared, firmly planted on the ground. i.e. lower legs and thighs forms a 90 degree angle.
I don't believe in using exercise ball. From an NYT article, it says that it only burns 4 more calories per hour and no evidence that it improves posture. Better off stand up and walk around every hour or so.