Correct Sitting Posture on an Office Chair

To maintain the body's natural curves and reduce musculoskeletal strain, the following points should be followed for a correct sitting posture on an office chair:

1. Adjust the Seat Height
   The seat height should ensure that both feet are flat on the ground, with the thighs and lower legs forming an angle of 95°-100°, or the thighs parallel to the ground and the knees bent at 90°. If the chair is too high and causes the feet to hang, a footrest should be used; if the chair is too low, it increases pressure on the knees and should be adjusted to the appropriate height.

2. Maintain the Correct Sitting Angle
   Lean back slightly, with the backrest and torso forming an angle of 100°-110°, allowing the back, especially the lower back, to fit snugly against the backrest. If the chair is equipped with lumbar support, adjust it to support the natural curve of the lumbar spine (between the third and fifth lumbar vertebrae), with a thickness that maintains a slight forward convexity of the lower back. Additional support can also be provided by adding a lumbar cushion or memory foam pad.

3. Properly Support the Arms
   The armrest height should be adjusted so that when the elbows hang naturally, the forearms can rest easily on the armrests or desktop, with the upper and lower arms forming an angle close to 100°. This position reduces tension in the shoulder and neck muscles and upper limbs, preventing fatigue caused by hanging arms.

4. Optimize Screen Viewing
   The monitor should be raised so that the line of sight is level with the top edge of the screen, with the top of the computer screen level with or slightly lower (10-15 cm) than the eyes, and the distance maintained at 50-70 cm, with the centerline of the screen aligned with the bridge of the nose. Laptop users are advised to use a stand to elevate the screen and connect an external keyboard to maintain the correct sitting posture.

5. Standardize Foot Position
   Both feet should be fully in contact with the ground, shoulder-width apart, avoiding crossing the legs or sitting with legs crossed, and keeping the ankles at a 90° angle. If height is insufficient and causes the feet to hang, a footrest should be used for support; women wearing high heels are advised to keep a pair of flat shoes for changing to reduce pressure on the feet and lumbar spine.

6. Take Regular Breaks
   Stand up and move around for 1-2 minutes every 30-40 minutes, performing micro-movements such as tilting the head back or contracting the shoulder blades, or engaging in intermittent activities like getting water or using the restroom to relieve static muscle load and prevent health risks associated with prolonged sitting.

The correct sitting posture should be adjusted according to individual body characteristics. If chronic lower back pain or discomfort persists, it is advisable to consult a professional doctor or physiotherapist for further evaluation.