Read this guide on what you need to know before spending $500 or more on an ergonomic chair.

Buying an ergonomic chair can be confusing, but it doesn't have to be. Knowing what to look for makes the difference between getting a chair that will make an instant, dramatic improvement in your energy levels and just getting an expensive chair.

This guide will teach you the key to choosing the right ergonomic chair--understanding how sitting works. Sitting is such a basic task that it seems like it ought to be self evident. However, very few people, even among professional ergonomists, really understand the mechanics of sitting and how a chair should fit to your body. After learning the keys to great sitting you will be able to confidently purchase a chair knowing that lasting comfort and pain relief are just a few moments away.

How Marketing is Misleading

Seating marketers have learned through studies that on average a person will sit in a chair for only eight minutes before making a purchasing decision. Unfortunately, how a chair feels after eight minutes and how it feels after a full day of sitting are often very different. Cushy seats that feel like sitting on a cloud lose their shape as you sink deeper and deeper into them. After a day on that chair with the awesome lumbar support, you find that your hips are stiff and sometimes your tail bone hurts. You may even find that you gravitate towards the front of the chair and don't even use the lumbar support. You simply can't rely on a brief sit test alone.

Another one of the easiest traps to fall into is what I call "The Ergonomic Chair Back Fallacy." Ergo chairs are often marketed for the latest and greatest chair back. These claims range from a new super fabric to the best lumbar system ever. However, the most important factor in buying an ergonomic chair is not the chair back. Avoid this trap. Buying a chair based on comparing the backs is a recipe for failure.

How Sitting Works

Before we get into the details of sitting, let's consider that the human body was designed for motion rather than static sitting. Despite being scolded as a child for fidgeting in your chair, moving around while seated is good for you. Many ergonomic brands, such as Varier and Humanscale, have caught onto this with "Active Movement" collections that encourage movement while sitting.

The single most important factor to consider when sitting is your hip angle. Likely as a result of being built to stand and run, the human body naturally prefers a 130 degree hip angle--close to what you would experience with your front leg while in full stride. Astronauts also float into a 130 degree hip angle in zero gravity.

This creates a natural conflict when we try to jam our bodies into a 90 degree chair. You wind up sliding your bottom forward in your chair and tilting your pelvis back as your hips constantly try to open up. The upright chair back then forces your upper back up rather than leaning back in line with your pelvis. Your head then sags forward as your chest collapses towards your stomach. Stop and check yourself right now, you are probably in this position. This is the classic "C" shaped spine with a flattened out lower back.

You may also find yourself doing "the chair dance" throughout the day without even realizing it. You start off with good intentions and good posture, but eventually you get uncomfortable and your bottom slides forward as you sag into the chair. Being in the "C" shape for too long is also very uncomfortable, so you sit up straight again for a time and then repeat the cycle.

Correcting your hip angle automatically fixes the flattened out lower back problem that most ergonomic chairs try to fix with lumbar support. The best way to get a tried and true sense of this feeling is to sit in a kneeling chair. If you've never done it, you will notice a tremendous difference. Your body naturally and effortlessly lifts into an upright seated position with a perfect "S" curve in your spine. While there may still be some value in having a chair back, it is actually not necessary at all for sitting with good posture.

Standard ergo sitting advice advocates planting your feet flat on the floor, legs parallel to the floor, and sitting upright or leaning slightly back. Already we have violated the 130 degree hip angle if we follow this advice. Leaning slightly back acknowledges the need for a wider hip angle, but when you lean back it becomes impossible to keep your head in line with your spine. It is extremely uncomfortable to hold your head back for a long period of time, so you wind up stooping it forward. Stooping for a long period of time also hurts your neck and ruins your posture.

The second most important rule in good sitting is to support weight with bones, not flesh. Just like the support beams of a building, your skeleton was designed as the load-bearing structure for your body. The two main contact points for sitting are your bottom and your feet.

Your hips come down through your bottom in two points referred to as the "sit bones." Whenever you sit, your weight should be firmly centered over those bones. This is where many super cushy chairs fail because they are so amorphous that they don't allow your bones to properly support your body. Chair seats that have excessive grooves for your bottom and thighs also generally violate this rule.

Your feet, obviously, come in contact with the floor. The body balances itself around the feet, so having them planted firmly on the floor helps maintain good seated posture. Your feet actually have two main contact points with the floor, through the ball of the foot and the heel. You want to keep your weight balanced evenly from front to back on these two points. There is, however, one exception to the feet rule. For kneeling chairs, weight should be balanced on the kneeling pads through your shin bones. It's generally not a good idea to put the weight directly on your knees as the name might imply.

The Ideal Sitting Position

To summarize the last section, this is the ideal sitting position we are trying to create:

1. Hips open to a 130 degree angle.
2. Weight centered solidly over sit bones.
3. Feet flat on floor (or shins if a kneeling chair) with weight distributed evenly between the heel and ball of the foot.
4. Upper body straight up, head in line with spine.

With these conditions in place it's all but impossible not to sit upright and feel the relief of pain-free, great posture.

Ergonomic Factors to Look for in a Chair

Now that we know how sitting works and the ideal sitting position, all we have to do is find a chair that let's us do it. Here are the features to look for when choosing a great ergonomic chair that will deliver lasting comfort and pain relief:

Purpose-built 130 Degree Hip Angle or Adjustable Seat Tilt

Specialty chairs that come purpose built for a 130 degree hip angle are few and far between, but excellent chairs well worth seeking out. At the very least your chair should have adjustable seat tilt. You want to make sure that it tilts forward. Many chairs only go back, which is useless.

Ball chairs have also become popular recently, but they fail the hip angle criteria since you have to sit so far towards the front of them to get the right angle that they shoot out from underneath you.

Seat tilt is the most important part to get right for an all-day comfort chair.

Firm, Planar Seat Pan

In order for your sit bones to do their job correctly, you need a firm seat that will not collapse after a day of sitting. A little cushion is still okay and probably desirable. Avoid ball chairs and chairs with excessive grooves for your bottom. Remember, we want to support weight with bones, not flesh.

Front Edge of Seat Pan Curves Down

The worst thing is to have a chair that curves up and digs into the back of your thighs. The front edge of the seat pan should always curve down. Aside from overtly upward curving seats, many chairs are built with a hard frame around the edge and a minimally supported seat that sags down in the middle. Also avoid seat pans that are too long since they will dig into your legs as well.

Firm Chair back

Similar to the seat pan, the chair back should be firm. Sinking into an over cushy seat back tends to round your back and push your shoulders forward, which causes pain over time. You want to feel your back expanding upwards and outwards when you are resting against the chair back.

But What About Lumbar Support?

If we got the first part right and our hip angle is correct, lumbar support is largely a non-issue. You can't help but maintain a pain-free, comfortable "S" curve in your spine when your hip angle is correct. Avoid chairs with excessively curvy lower backs. You can also pass up expensive chairs that try to sell you on their amazing adjustable lumbar system.

Monitor Height Also Affects Sitting Ergonomics

If you plan on using your chair in front of a computer, it is critical to have your monitor at the right height. If your monitor is not at the right height you will experience pain and discomfort no matter how good your chair is. Your head naturally tries to position itself so that your eyes are in the middle of your screen. However, you can use this to your advantage. Your eyes seek the middle of the screen so unconsciously and strongly that you will drift into great, pain-free posture without even thinking about it. Simply get your chair set up in comfortably good posture and then position your monitor so it is centered in front of your eyes. Monitor arms and laptop stands are great adjustable tools for this.

Conclusion and the Bottom Line

Congratulations on taking this step in learning more about your health and how to take care of your body with a great chair. A good ergonomic chair is the single most important investment you can make in relieving discomfort from a day of sitting and giving you more energy for your life.

Equipped with the rare knowledge of how sitting actually works and what to look for in an ergonomic chair, you can now confidently evaluate and choose from the best ergonomic chairs. Even without sitting in a particular chair, you will be able to look at it and have an intuitive sense of whether it will provide you with all-day comfort and pain relief.

Even if you just do these three things it will be difficult to go wrong in picking a chair:

1. Look for capability of 130 degree hip angle.
2. Look for firm seat pan that curves down at the front edge.
3. Avoid getting trapped in competitive hype over the latest, greatest chair back.

You can browse some of my favorite ergonomic office chairs here.

Good luck and happy sitting!

Luanne Perrera

Body Correct Living