What Is the Best Ergonomic Office Chair?
What Is the Ergonomic Office Chair?
The ergonomic office chair is created according to the theory of “ergonomics”. With various data of the using process of office chairs summarized and combined with the modern chair manufacturing technology, the ergonomic office chair is developed to fit for the correct sitting position of human body and adjust the comfort.
It can not only meet the sitting needs, but also enjoy the comfort and health of “sitting”. This is aligned with the “people-oriented” principle of industrial design. The design follows the principle that releases nature, adjusts for comfort, and is suitable for a variety of body types. What’s more, it’s mainly made of environmentally friendly materials.
The Main Design of Ergonomic Office Chair
How does the design of the ergonomic computer chair relieve human fatigue?
- Headrest: The height and angle of the headrest are adjustableaccording to the needs ofhuman body. Besides, corresponding adjustments can be made for different body types to fit the neck and guide the sitting posture to reduce fatigue.
- Chair back: Back with lumbar pillow or curved lumbar back. The best support position for the waist is the third and fourth spine. The height of the entire chair back is adjustable, which can easily meet the needs of users of different body types and reduce most of the body weight carried by the lumbar vertebrae.
- Seat cushion depth: For users of different heights, the seat cushion depth can be adjusted to an appropriate position to guidethe correct sitting posture. It has a natural release effect and thus improving thework efficiency.
- Armrest: Adjust the height and angle of the armrest to make the transition between the hand and the table smoother and prevent the carpal tunnel syndrome.
Angle free adjustment, reclining memory locking system, stepless locking, curved back design, bow frame strength and elastic treatment, armrest arc streamline treatment, etc.
Design Basis of Ergonomic Office Chair
Physiological characteristics of human sitting posture
The most natural posture of human is the upright standing posture, and the spine is basically in an S shape when standing upright. But compared with the upright standing posture, the sitting posture is conducive to the blood circulation in the lower part of the body and reduces muscle fatigue of the lower limbs. At the same time, the sitting posture is also conducive to keeping the body stable.
However, the pelvis will tilt backward when sitting, so the sacrum at the lower end of the back is also tilted, causing the spine to change from an S shape (normal shape) to an arch shape. And that puts a lot of pressure on the intervertebral discs of the spine, causing low back pain and other diseases. Improper design of the chair seat surface will cause compression of the thighs. And then hinder the blood circulation of the lower limbs, resulting in numbness of the lower limbs.
With the intervertebral discs of the spine under pressure, the incorrect sitting postures can not reduce the load on the waist, but will increase instead. Sitting with a straight waist is beneficial to reduce the pressure in the intervertebral disc, but the muscle load increases. While sitting with a bent waist is beneficial to the muscle relaxation, but it increases the internal pressure of the intervertebral disc. Therefore, the inclination and shape of the backrest can affect the intervertebral disc and back muscles.
Size basis of human sitting position
A. Sittingheight: Office chair 450-550mm. Sitting height generally takes the 5th percentile value of calf length plus foot height as the design basis. The front edge of the seat should be 30-50mm lower than the height of the human knee fossa, and be made into an arc with a radius of 25-50mm. The sitting surface cannot be too high or too low.
- H = calf popliteal height + shoe thickness (20-40mm)-appropriate clearance (10-20mm)
B. Sitting width: generally greater than 380mm. The armchair is not less than 460mm. Resting chairs such as sofas are larger than 480mm, generally 520~560.
- B = human shoulder width + winter clothing thickness + activity margin
C. Sitting depth: 400~440mm is adopted in the national standard. And the seat depth for rest chairs such as sofas can be larger, 480~600mm. Design with the 5th percentile value of sitting depth.
- T=Length of thigh in sitting posture -60mm (clearance)
D. The inclination angle of the sitting surface and the backrest: The inclination angle of the sitting surface (backrest) refers to the angle between the sitting surface and the horizontal plane. The rest chair is generally 19°~20°; 98°~112°. For the work chair, since the seated person needs to lean forward during work, the inclination angle should not be too large. It can be 4°~6°; 95°~100°.
E. The height of the backrest:Generally it is appropriate to be on the lower edge of the scapula. A waist pad should be set at the waist, preferably 250mm. The waist position varies with the inclination of the backrest.
F. Armrest height: The height of the armrest refers to the distance from the upper edge of the armrest to the sitting surface. The main function is to support the weight of the arm and reduce the burden on the shoulders. The height of the armrest is generally 200-300mm above the effective thickness of the cushion.
G. Chair cushion: When a person is sitting, about 75% of the body’s weight is supported by the parts around the ischial tuberosity of about 25c㎡. Sitting for a long time will produce stress fatigue, causing pain and numbness in the buttocks. If a soft and hard cushion is added to the sitting surface, the contact support area can be increased and the pressure can be dispersed.