What is ergonomic office chair?

 Ergonomic mesh chair, the earliest application can be traced back to World War II, it is used to facilitate long-term flight operations which is needed for the pilot seat engineering transformation. In 1994, Aeron, an ergonomic mesh chair designed by Stumpf and Chadwik, was released. Their original design was to provide a breathable and comfortable chair for people who are unable to move and need to sit for a long time. 

The soaring demand for workplaces and the continued increase in purchasing power at that time have made it to be the most successful ergonomic office chair until today , and it marked the beginning of an era in which humans need to spend more time working at computers desks to make money. Ergonomic chair is a productivity tool designed to maintain a comfortable sitting position by scientifically considering a large number of human data samples and comprehensively considering life, work and other application scenarios, which aims to improve the efficiency of tool use or work efficiency.

Why do you need ergonomic chairs?

In recent years, the harm of being sitting for extended period time has been mentioned frequently in news, social medial and scientific research. For example, sitting for a long time leads to diseases such as obesity and high blood pressure; sitting for a long time can affect people's memory and cognitive ability; people who are sedentary have a 40% higher risk of death than those who are less sedentary; people who are sedentary are 2.5 times more likely to develop diabetes than those who are less sedentary. The above life-threatening diseases may be appalling to you, but it is more than that. The common problems such as lumbar muscle strain, protruding lumbar intervertebral disc, cervical pain and sciatica are all caused by sitting for a long time.

1. Improper  chair  back and lumbar support cause lumbar muscle strain.

First of all, from an anatomical point of view, look at the root cause of all these hazards-- the spine.

When a person is in a standard standing posture, the cervical vertebrae, thoracic vertebrae, lumbar vertebrae and sacrum show four normal physiological curvature, which makes the human body feel the most relaxed because of the force balance between the lumbar core muscles. But when we sit down, without proper seat back and lumbar support, the pelvis tends to lean backward, the cervical and lumbar vertebrae change from kyphosis to kyphosis, the thoracic kyphosis is more curved, and the force balance of the lumbar and abdominal core muscles is broken. After a long time, you will naturally feel sore and tired. This is how the lumbar muscle strain comes from. The back and lumbar of the ergonomic office chair are designed according to the normal curvature of the human spine. You only need to lean on the back of the chair, which can support the spine properly and help you maintain the normal curvature of the spine easily.

Improper angle of chair back causes lumbar disc herniation.

2. Inappropriate headrest causes cervical spondylosis

The cause of cervical spondylosis is basically the same as lumbar disc herniation, long-term desk work, and bow head to play with mobile phones, cervical vertebrae bear far more weight than the head, cervical disc herniation, compression of nerves appear pain, numbness and other symptoms. Most computer chairs are not equipped with headrest, or headrest cannot be adjusted independently. The headrest of ergonomic chairs can independently adjust their height and angle to meet the needs of sitting, leaning back, for lunch break and so on. 

3.  inappropriate cushions and armrests which is difficult to maintain the correct sitting posture

There are two round bones at the lowest end of the human pelvis, referred to as ischial bones. If the sitting surface of the chair is too hard, the ischial bone will fully bear more than 75% of the body weight, and for a long time, problems such as sciatica may occur. But if the chair surface is too soft,  such as some boss chair and sofa, the person will sink in, which will make the femur rotate upward, the hip muscles will be oppressed, which will affect blood circulation and nerve conduction, leading to numbness, edema and other problems.

The sitting surface of the ergonomic chair can provide moderate elastic support for the buttocks and legs, avoid being too soft or too hard, and share the pressure to the maximum extent, coupled with the design of armrest  with adjustable height, it can solve this kind of problem very well. To sum up, ergonomic chairs provide necessary support for our neck, back, lumbar, buttocks, legs and arms, help our spine maintain normal physiological curvature, and make it easy for us to maintain the correct sitting posture. Avoid the harm of sitting to the maximum extent. However, The biggest difficulty in buying an ergonomic office chairs online is that you can't experience it first. Unlike in offline store, you can get feedback on whether it is appropriate and comfortable to sit for a while, but it is not appropriate to buy it online, and it is also troublesome to return and exchange goods.

How to  choose an ergonomic office chair for you?

1.  seat: the core secret of comfort (most important one)

 Chair seat is one of the core of the ergonomic chair, because it is the basis for you to maintain a good posture, the seat needs to pay attention to two properties: the material and the seat area.

(1) material.

Entry level- entry-level chair surfaces include ordinary sponges and nylon mesh , and the chairs are all stacked with ordinary sponges, which will collapse after sitting for a long time, stuffy and hard

Middle level- The middle level ergonomic desk chair  include high-density sponges and Taiwan Yixing, Yida and other mesh, which are generally used on the middle-level ergonomic mesh chairs.

Middle-to- high level- the middle to high ergonomic chair surfaces all use imported mesh. Their advantages are strong elasticity, good toughness, providing sufficient support, and at the same time, they are not easy to collapse. After 100000 stress tests, the elasticity loss is only 2.6%. The disadvantage is that the price is expensive, the supply is limited, and the ordering cycle is long. 

(2) Seat surface zoning.

As we have analyzed above, in the sitting position, the sitting bone is under the greatest pressure. The more you go to the front of the thigh, the less the pressure is. The best solution is to design different areas of the chair surface into different tension, and the ischial pressure is the highest, so the net surface tension of the pelvic support area should be the minimum, and the net surface tension of the leg area should be relatively large.

2. Chair back: spine Guardian

The back of the ergonomic office chair is specially designed for the thoracic and lumbar vertebrae, which can maintain the thoracic and lumbar vertebrae in natural curvature, so that the muscles of the back and waist can be relaxed and do not feel tired after sitting for a long time.The back of the chair also needs to pay attention to two properties: design and adjustment.

(1) Design.

Entry level - entry-level chair back does not have a waist rest, or only a fixed waist that cannot be adjusted independently, relying on the curvature of the chair back frame to provide support for the back and waist, because the waist is less stressed, so the muscle tension will be larger, sitting for a long time will still be tired.

Middle level- the seat back of the middle level can be adjusted independently, and the height of 3-4 lumbar vertebrae can be adjusted up and down or adjusted back and forth to change the curvature of the chair back. the sense of waist support is strong, which can meet the needs of people of different heights. The disadvantage is that overweight people may feel that the waist is compared, and the waist support position will run up when leaning back.

Middle to high level- most of the middle to high level seat backs use double-back design, which is also the current mainstream design, which avoids the problem of fixed waist and running waist, but people of different weight feel different, and people of small and medium size will feel strong support. people with large weights will feel soft.

Top level- Top lumbar support and sacral support can be taken into account at the same time. Sacrum is the foundation for lumbar vertebrae and thoracic vertebrae to maintain normal physiological curvature. If the sacrum can be easily straightened through lumbar support, then the curvature of lumbar vertebrae and thoracic vertebrae can be guaranteed naturally.

If you are overweight or have problems such as lumbar disc herniation, it is recommended that you first consider will be the double-back design of the seat back, which is safer for the lumbar spine and can also be used by small and medium-sized people who like the sense of the waist, and the function does not need to be too gaudy. You only need to be able to adjust the height up and down with the back of the chair (to adapt to different heights), and the front and rear elasticity is soft (to adapt to different weights).

(2) Adjustment

As analyzed earlier, the back of the ergonomic chair must be able to lean back so that the pressure on the seat and spine can be evenly distributed. If you want to sit more easily, the back angle of the ergonomic chair should reach at least 110 °. Of course, the back of the chair needs to have appropriate support, if the support is too small, people with large weight will fall down as soon as they lean on and cannot sit and work; if the support is too strong, people with small weight will not be able to lean back, so ergonomic office chairs must provide back adjustment.

3. Headrest: cervical vertebra guardian

The role of the headrest is the cervical vertebra, the main purpose is to remind you not to bow your head and provide support for the cervical vertebra when leaning back. Entry-level headrest can adjust height up and down, slightly better one can rotate angle, can adapt to people of different height, this is the basic requirement for headrest, but it is basic decoration when sitting, only a little back or lunch break can support to the cervical vertebra.

The headrest of the middle level can be adjusted not only up and down, but also back and forth. (special)the use scene is more comprehensive, in addition to up and down, front and rear adjustable, rotatable, but also can be turned backward into headless pillow, the adjustment range is very large.

4. Armrest

The purpose of the armrest  is to support the arm and reduce the fatigue of lifting the arm on the shoulder, because everyone's workbench height is different, so as long as the armrest l can adjust the height.

5. Gaslift, five-star foot, castor

We often receive such feedback, the same chair, some people say it is very comfortable, some people say it is uncomfortable, that is because everyone's height and weight is different, feedback about the strength and support position is not the same.Choosing an ergonomic chair is like buying clothes and shoes, you have to consider your height and weight. If you are overweight, obese, weight 80kg or above, first consider the ergonomic chair with high-density sponge cushion. In this case, do not buy a chair with cheap nylon mesh , which will not take long to fall into shape.

The main factor that different people have different feeling of sitting is height, to be exact, it is the sitting height when sitting. If the chair seat is too high than your sitting height, the thighs will be oppressed, affecting the blood circulation. If the seat height is too low, there will be more pressure on the sitting bones, affecting the foundation of sitting posture. So how high is the seat height suitable for you? 99% of the articles did not elaborate on this point.

According to the ISO table and chair standard, the national table and chair standard, the ergonomics data, and the data provided by the Ergonomics textbook, I will directly help you summarize a reference table. According to the latest official figures:

Conclusion

In other words, male compatriots with height 169cm should choose ergonomic office chairs with 42-44cm height adjustment range, and female compatriots with height 158cm should choose ergonomic chairs with 40-42cm height adjustment range. However, according to the ergonomic chairs on the market at present, the height of the lowest seat is about higher than 43cm, and it is very difficult for a considerable number of people to buy an ergonomic chair of suitable height. In this case, it is necessary to install a pedal to raise the foot.