Ergonomics: Your Work Chair

Ergonomics: Your Work Chair

Proper workspace ergonomics can lessen the risk of musculoskeletal (MSK) problems and help improve the symptoms (e.g. discomfort, pain, and muscle fatigue) of problems that may be present. 

Your work chair, and how you use it, impact the health of your MSK system including your neck, shoulders, and back and even your wrists, hands, and ankles.

Since you spend a large part of your workday in a chair, you should understand and implement good chair ergonomics.

A Word About Ergonomic Recommendations

We provide instructions about adjusting your chair and workstation in a certain way, however, keep the following in mind:

Although it may seem that we want you to stay in a certain position, once you adjust your chair, it is most important to change your position throughout the day. This means you may make minor changes to your chair settings, change your body position in the chair, or go from sitting to standing and to sitting again.

You may see different recommendations for ergonomic positioning, depending on the expert, as well as the chair manufacturer.

The Ergonomics Center At North Carolina State University: “Alternating postures throughout the day can be instrumental in preventing musculoskeletal disorders by giving the body postural breaks and improving blood circulation. Industry research suggests that sitting should be combined with standing and/or moving throughout the day.” As an example: 

  1. Sit in an ergonomically correct position for 20 minutes, then;

  2. Stand for 8 minutes, and then;

  3. Move - do some light stretching or walk for 2 minutes. 

Ergonomic Office Chair

An ergonomic office chair can be adjusted to fit your body, create an optimal desk-sitting position, allow for efficient completion of tasks, while protecting your musculoskeletal system.

Your chair is critical to your overall ergonomic workspace which also includes your computer/laptop, keyboard, monitor/s, lighting, and accessories, and time for breaks and stretching.

When your chair is properly adjusted, your spine should be straight (ears above shoulders) with your:

  • Feet resting comfortably on the floor or on a small footrest

  • Thighs resting evenly on the seat pan, the top surface of the seat

  • Lower back supported by the curve of the chair

Some experts say: 

Although your spine should be straight - i.e. ears above shoulders, slightly reclining your chair lessens the stress on your back. 

Ergonomic Chair Features

When selecting a chair, there are some basic features, all of which should be adjustable. They are the seat and seat pan, back, and armrests

Small adjustments can make a big difference in your comfort. Adjust your chair so it fits YOU, then move on to make changes to the rest of your workstation. 

Some experts say: 

Adjust the height of your chair based on the position of your keyboard and monitor. Your forearms and hands should be aligned and your elbows bent at a 90-degree angle. Then add a footrest, if needed, to support your feet.

Seat And Seat Pan

Seat Height

Goal: Your thighs should be parallel with the floor and your feet should also rest comfortably on the floor or a footrest.

When standing in front of the chair, the seat pan should be level with the top of your calves, just below your knees.

To Change Seat Height

Lift the chair paddle, while you are off of the seat to raise the height; Lift the paddle while seated, to lower it.

Seat Pan Depth

Goal: There should be adequate space (a few inches/centimeters) between the back of your calves and the front of the seat pan. Your back should be comfortable against the backrest.

The front edge of the seat pan should also be curved. You should be able to angle the seat pan up or down and keep it in a fixed position, if desired. It should also be a comfortable and breathable surface.

To Change Seat Pan Depth

Adjusting the seat pan depth depends on the manufacturer and model. You may have to:

  • Pull up on the paddle located under the seat

  • Pull up on the bar that is under the front of the seat

  • Pull up on 2 levers, one on each side of the seat

  • Turn the knob on the side of the seat

Seat Pan And Backrest Angles

Since the seat pan and backrest angles work together, they’re both discussed here. There are three postures based on the seat pan and backrest.

Goal: There should be proper alignment with an angle between the back and thighs of 90° or more.

  1. Reclined posture: level seat pan or very slight backward tilt to seat pan + slightly reclined backrest

  2. Standard posture: level seat pan + backrest straight up 

  3. Forward posture: seat pan tilted very slightly forward (5-10°) + backrest straight up (Note: may need to adjust backrest until you feel upright)

To Change Seat Pan and Backrest

Chair tilt mechanisms are located under the seat pan.

Types of seat pan/backrest tilt mechanisms

  • Multi-function (also called synchronous): backrest and seat pan tilt independently

  • Forward tilt: adjusts the front of the seat pan up and down (usually part of a multi-function tilt mechanism)

  • Forward glide: backrest reclines and seat pan adjusts forward and down 

  • Single point: backrest and chair pan tilt together 

Back

Back Or Backrest Height

Goal The lumbar support of the backrest should fit your lower back - i.e the small of your back. 

The backrest should also recline separately (and stay in a fixed position if desired) from the seat.

To Change Back/Backrest Height

To adjust the backrest height follow these steps: 

  1. Raise it to its highest position

  2. Lower it to its lowest position

  3. Raise it notch-by-notch, so the lumbar support fits comfortably into the curve of your lower back

Backrest Angle

Since the seat pan angle and backrest angles work together, see Seat Pan And Backrest Angles above.

Armrests

Armrest Height

Goal: When using your keyboard, the armrests should be just below your elbows. Your elbows should be off of the armrests and at right angles to allow your shoulders to be in a relaxed position.

To adjust one of the armrests, bend your arm so your elbow is at a right angle. Raise the armrest so your forearm rests on it. Do the same with the other side. The armrests should be raised evenly, just below your elbows, and in line with your work surface. The front part of the armrests should also be curved.

To Change Armrest Height

Depending on the manufacturer and model of the chair, there may be a button, ratchet or notch system, lever on the chair back, or a bolt system to adjust the armrests.

Armrest Width and Angle

Goal: Each armrest’s width and angle (pivot) should properly support the wrists, forearms, and elbows.

When adjusting the width, you should be able to relax your shoulders with your forearms resting on the armrests - you shouldn’t need to reach for the armrests. 

Angle the front of each armrest so that you can easily reach your keyboard - your forearms should be on the armrests. Make sure the armrests aren’t in the way when sitting down or getting up from your chair.

To Change Armrest Width and Angle

The adjustment mechanism depends on the manufacturer and model of the chair. It may be with: the armrest itself; a knob under the armrest, or a lever or button underneath the seat.

Chair Base

Although not for ergonomic purposes, the base should be stable to avoid tipping over - most have a five-point base.

The Rest Of Your Workstation

While this information focuses on your work chair, the rest of your workstation should be arranged in such a way that it enhances the ergonomics of your chair.

Keyboard

Your wrists should be straight while using your keyboard. Use a wrist rest, if needed. 

Some Experts Say:

Avoid using a wrist rest because it may not keep your wrists straight. Instead, use a palm wrist rest.

  • You can float your wrists and hands over your desk, but only for short periods of time as it leads to fatigue

  • A low-profile keyboard is a good choice - when you use one, your wrists are straight and it allows your desk to support your forearms

Laptop Setup

Use a laptop stand or docking station so the monitor is at eye level (see next section for details). Use an external keyboard (see Keyboard above).

Monitor

Your eyes should be aligned with the top one-third of the monitor screen with your neck straight (some experts say your eyes should be level with the top line of text).

The monitor should be positioned so that there are between 20-40 inches (51- 102 centimeters) between your eyes and the screen. That means about an arm’s length away, using your middle finger and with your back resting on the chair back. 

You should be able to easily view the screen. If it’s hard to view text, you can increase the font size or zoom in. You should also have proper lighting with as little glare as possible.

Footrest

Use a footrest if you are unable to rest your feet comfortably on the floor. Make sure your thighs are parallel to the floor.

Ergonomics: Stretching and Breaks

Stretching and taking breaks are critical to proper ergonomics. No matter how well you adjust your chair and arrange your workspace, you need to get up and move around.

Stretching

Regular stretching exercises help to increase flexibility and strength and decrease pain and fatigue. You should take stretch breaks throughout the day - before your muscles are tired and you feel discomfort.

Breaks

Break periods are very beneficial to prevent and lessen musculoskeletal pain. They give you a chance to rest tired muscles. They also allow time for you to stretch and change positions. You might use the time to do stretching exercises or go for a short walk, even if it’s inside your office or home.