So you’ve bought an ergonomic chair…now what? In this post we will be discussing the multiple factors and variables to consider when setting up your ergonomic chair to ensure you are in the most comfortable, ergonomic position possible.
1) Seat pan should allow the thighs to be parallel to the floor. Feet should be resting FLAT on the floor. If the feet are not resting flat on the floor circulation to the lower leg and foot will be impaired.
2) Seat pan depth. Ask the staff member to sit with their back supported by the chair back. Adjust the seat pan so the front edge of the seat pan be positioned so you can place 2 fingers behind the back of the knee. If the seat pan edge is compressing the back of the knee it will impairing the nerves and circulation in the leg.
3) Adjust the seat back to provide the best low back (lumbar) comfort. Adjust the chair back to between 100 and 105 degrees (slightly reclined). Being slightly reclined this decreases the pressure on the low back.
4) Armrests – if you choose to have armrests on your chair, they should be adjusted to provide support to the FOREARMs when at rest. If your forearms are pressing down on to the armrests it will drive up your shoulders up causing shoulder and neck pain. If you rest your elbows on the armrests you can compress the nerves of your forearms.
5) Adjust the workstation to allow forearms to be parallel to for floor or tilted down slightly from the elbows. Additional note. Having the keyboard above the elbow will increase muscle tension to constantly lift and maintain wrists and forearms above the keyboard.
When the seat pan is raised up adjust the following:
Angle Seat pan down BUT keep feet FLAT on the ground.
Increase the seat back angle to keep the back supported.
Armrests may also need to be adjusted.
NOW that the chair is adjusted correctly, raise the desk up to place forearms parallel to the floor or with elbows
slightly above the keyboard tray. If the desk cannot be adjusted, raise the chair up and provide a footrest to
provide support for the feet.
If you have staff with injuries to knees, hips, or low back OR if Obese. To reduce pressure on those body parts, do the following.
• Adjust the seat pan down (slightly more than above) raise the seat height up BUT be sure to keep feet flat on the floor.
• Increase the angle between the seat pan and the seat back
• Train the injured employee to push the chair back away from the workstation. Next rock their body in the chair, forward, back, and then forward again and while exiting the chair press down on the armrests and step out on to the Uninjured leg. By rocking back and forth while exiting the chair this decreased pressure and because their body is in motion and while pressing down on the armrests it makes it easier for them to exit the chair.
Next –A fixed posture is never a good thing to maintain throughout the day. I recommend adjust the chair height, seat pan angle and chair back angle often. Stand up and then sit once every 15-20 minutes. Ideally, if a sit stand electric desk is available, suggest staff stand 10-15 minutes per hour. If they are sitting at a Crank up desk, crank the desk to standing height just before going to breaks and lunch, on return to stand 10-15 minutes then lower the desk back to sitting height. Also, their monitor may also need to be adjusted. Position the monitor so that the eyes positioned slightly above monitor height. IF they are wearing Bifocals or graduated lenses, monitor should be adjusted 3-4 inches BELOW eye height to prevent angling head back to view the monitor clearly.
The above OSHA web site has illustrations you can view. Things I like about the illustrations. Angled down seat pan feet flat on the floor or supported by a footrest. Good upright posture.
What I DON’T like – elbows grounded to armrests and keyboard tray is above the elbows.