Office Chair Armrest Adjustment

The adjustment of office chair armrests should follow scientific principles, using the 'right-angle positioning method' to precisely adjust the three key dimensions of height, front-back position, and width, thereby avoiding shoulder, neck, and wrist strain caused by incorrect adjustments. Additionally, adjustments should be made according to the specific model of the chair.

I. Hazards of Incorrect Adjustment

Improper adjustment of armrests can directly lead to a chain reaction of injuries: High armrests force the shoulders to hunch up, keeping the shoulder muscles constantly tense and increasing the risk of frozen shoulder. Low armrests leave the elbows hanging, causing excessive wrist bending to touch the desktop, which can compress the median nerve in the carpal tunnel over time, leading to carpal tunnel syndrome. Armrests that are too far forward cause the angle between the upper arm and torso to exceed 45 degrees, resulting in an imbalance in muscle tension on both sides of the cervical spine, which can trigger dizziness and neck stiffness.

II. Adjustment Steps Using the 'Right-Angle Positioning Method'

1. Height Adjustment
   First, adjust the seat height to ensure that your feet are flat on the ground and your knees are bent at a 90-degree angle. Sit up straight and let your upper arms hang naturally close to your torso, with your elbows bent at a 90-degree angle. Measure the vertical distance from the tip of your elbow to the seat surface (standard height: 20-25 cm). While adjusting, support the tip of your elbow with your hand and slowly raise or lower the armrest until it fully supports the weight of your arm, without causing your shoulders to lift or sink. If the armrests are not adjustable and are too high, you can place a 3-5 cm cushion; if they are too low, remove them or use a footrest under the seat to level the height.

2. Front-Back Adjustment
   After adjusting the height, move the armrests forward or backward until the bend point of your elbow aligns vertically with the edge of the desktop, allowing your forearms to rest naturally on the armrests and your wrists to lie flat on the desktop while operating the mouse and keyboard. If the armrests cannot be adjusted front-back, compensate by adjusting the distance between the seat and the desktop: sit up straight and extend your arm so that your fingertips just touch the edge of the keyboard, which indicates the appropriate distance.

3. Width Adjustment
   When your arms hang naturally, the distance between your elbows is roughly the same as your shoulder width. Adjust the width of the armrests so that the inner sides are in contact with the outer sides of your upper arms, with a gap of no more than 2 cm. For individuals with a larger build, the width should be 3 cm wider than the shoulder width; for those with a smaller build, choose armrests with an inward-adjustment function to prevent shoulder abduction or restricted movement, which can lead to strain.

III. Adjustment Methods for Different Models

• Gaotian Massage Therapist Model: There is a button on the side of the armrests. Press and hold it to move the armrests up or down to adjust the height.
• Jinyexing A03 Computer Chair: The rebound of the backrest is controlled by four screws inside the armrests, which adjust the tension of the springs. If the backrest does not rebound, slowly adjust the tightness of the screws (if too tight, the springs cannot stretch; if too loose, there is no stretching force).
• C100 Premium Edition: No specific adjustment method is mentioned in the text. It is recommended to refer to the product manual or contact customer service for guidance.