Adjusting Office Chair

Adjusting an office chair involves aspects such as seat height, recline angle, headrest, armrest height, and lumbar support to enhance comfort and health protection.

1. Seat Height Adjustment
   Seat height is a core factor affecting sitting posture. When adjusting, ensure both feet are flat on the ground, with the thighs and lower legs forming a natural bend of 95°-100°. If the chair is too high, causing the feet to hang, a footrest can be used to fill the height difference; if the chair is too low, the knee joints will bear extra pressure due to excessive bending, which may lead to joint pain over time. Adjustments can be made using the gas lift or knob beneath the seat, and a brief test sit is necessary after adjustment to confirm comfort.

2. Recline Angle Adjustment
   The recline function can relieve back muscle fatigue, but the angle should be chosen according to the usage scenario.

• Lever Adjustment System: The lever beneath the seat releases the recline lock, allowing angle adjustment through body leaning, and remains stable when locked.
• Knob Adjustment System: Usually located at the center of the lower seat, turning clockwise increases recline resistance (suitable for heavier individuals), while turning counterclockwise decreases resistance (suitable for lighter individuals). Some models allow separate angle adjustment.
• Pneumatic Adjustment System: Shares the lever with height adjustment, enabling smooth recline through pushing in different directions.
  Usage Suggestions: Choose a slight recline of 5°-10° for focused work; adjust to 15°-20° for relaxation or thinking; and recline to 25°-30° for short breaks, but avoid lying completely flat to prevent affecting blood circulation.

3. Headrest Adjustment
   The headrest should fit the neck curve to support the head's weight. When adjusting:

• Height Adjustment: Move the headrest up or down by pulling or pressing buttons, ensuring its top is level with or slightly lower than the top of the head.
• Angle Adjustment: Some headrests support forward and backward movement, adjusting to maximize the contact area between the neck and headrest, avoiding suspension or excessive pressure.

4. Armrest Height Adjustment
   Armrest height should match the position of the elbows when hanging naturally. The adjustment standard is that when the forearms are flat on the armrests or desk, the upper arms and forearms form an angle of about 100°. If the armrests are too high, the shoulders will hunch; if too low, the elbows will be forced outward, both potentially causing shoulder and neck pain. Some armrests also support width adjustment, which should be adjusted according to body type to fit snugly against the sides of the body.

5. Lumbar Support Adjustment
   Lumbar support is a key component for supporting the lumbar spine. When adjusting, position it at the 3rd-5th lumbar vertebrae (the most concave part of the back), and use a rotating or sliding mechanism to make the lumbar support protrude forward, creating a "lifting" sensation rather than a "pressing" sensation. If the lumbar support is too high, it may press on the ribs; if too low, it will fail to support the lumbar spine, potentially leading to lumbar spine deformation over time.

Precautions: After adjustment, maintain the "three 90°" principle—feet to the ground, thighs to lower legs, and upper arms to forearms all forming angles close to 90°, while keeping the back against the chair back and the neck in a neutral position. Regularly check the fixation of all components to prevent loosening and loss of support.