|Ergonomic Chairs (Adjustable seating)
|To fit different workers, or different postures for the same worker.
To avoid back pain by supporting multiple postures and/or “good” postures; to reduce muscle effort required in sitting.
Seated work is generally easier than standing work, and provides more stability for precision work.
|Possible Drawbacks or Misuse:
||Adjustments can be confusing even with instructions.
No single chair will be preferred by all users; many chairs and chair features can be uncomfortable.
Size extremes (very small or large people) are not well served by the seating industry. There are few office chairs appropriate for these people.
Sitting, especially upright or bent forward, is generally considered harder on your back than standing
Too much sitting and prolonged static postures appear to be an independent risk factor for a group of metabolic disorders that some have labeled Sitting Disease.
|General End-user Instructions:
|All adjustments and their purpose should be explained to the end user and posted in a central place. Here are general adjustment guidelines:
- Adjust the seat height so the Knees and hips are nearly level and the feet can be supported on the floor or a footrest.
- Adjust the back cushion so that the curve in the pad fits into your low back.
- Set the chair to recline back and, if necessary, adjust the recline-tension knob for comfortable support when leaning back. (Adjust the back tension so that it requires some additional pressure to recline.)
- Don’t feel that you have to stay in a fixed “correct” ergonomic posture. Changing positions is good.
Your best posture is your next posture. You need to move and change positions regularly throughout the day. Flex, extend, and wiggle your legs. Contract and relax your leg muscles. Stand, march in place and shift around. Get up and move on your breaks. Suggested alternatives:
- Upright seated posture as described above
- Reclined seated posture
- Thighs declined (back of seat positioned higher and tilted downward in front)
- Standing posture (best if keyboard/ mouse/ monitor are also higher to prevent forward bending and bent wrists)
||Multitudinous. Many adjustments allow:
- Backrest up-down
- Backrest tilt/ angle forward or back
- Armrest up-down
- Armrest in-out
- Armrest pivot
- Seat height up-down
- Seat angle (including forward tilt on some models)
- Lumbar support depth (backrest forward/ back)
- Various seat height mechanisms
- Tilt lock, tilt tension
- Various recline mechanisms (knee tilt, column tilt, synchronous), etc.
- Each adjustment can have its own character: range, ease of adjustment, stiffness.
Basic Considerations- these are the minimum features an ergonomic chair should have
- Height- adjustable seat
- Height- adjustable back rest/ lumbar support
- Recline or rocking back rest mechanism
- Arm rests that adjust for support or remove for clearance
- Seat size that matches your leg-length, seat-width, and weight requirements
- Controls that are easily operated from a sitting position
- Stable 5-star base
- The chair should not feel uncomfortable to you
Some chairs offer more passive ergonomic features and controls where, for example, the individuals’ seat pressure (weight) modulates the back support pressure without requiring manual tension adjustments.