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What is ergonomic office chair?

why do you need ergonomic chairs?

How to choose an ergonomic office chair for you?

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.

Ergonomics, it  first entered the public eye in 1976, when Herman Miller and designer Stumpf designed the chair Ergon Chair, which formally applied ergonomics to the product.

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.

Because there were few people who needed to sit for a long time at that time in which there was an outbreak of the internet industry in the United States.

The soaring demand for workplaces and the continued increase in purchasing power at that time have made it to be the most successful ergonomic 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.

Have talked a lot on this,then what on earth is an ergonomic chair?

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 and the abdominal core muscles that maintain this form of vertebrae. And there is no excessive stretch and contraction.

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.

For example, the back and waist muscles are stretched due to lack of support, and the abdominal muscles contract, which is equivalent to a continuous passive state of muscle exertion. 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 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.

Let's take a look at the force on the spine, assuming that the weight on the spine is 100kg in the standard standing posture (it is definitely not that large, for explanation only), and when we sit in the standard sitting position, the pressure on the spine will reach 150kg.

If it is the above posture of stooping and working at a desk, the pressure on the spine can be as high as 180-270kg. Can you imagine what it would be like to have a person with a heavier upper body than you when you are working at a desk?

Secondly, under normal conditions, the nucleus pulposus of the lumbar vertebrae  is evenly loaded in the middle of the intervertebral disc; when leaning forward, the great pressure on the spine squeezes the nucleus pulposus backward.

After continually accumulated extrusion, lumbar intervertebral disc fiber is destroyed,  it will gradually bulge, protruding, the formation of well-known lumbar intervertebral disc herniation, more serious and even prolapse, it is not just pain.

From the above analysis, there is no doubt that the most comfortable posture is lying down, but working lying down is obviously impractical, so if you want to avoid problems such as lumbar disc herniation, you need an ergonomic chair with an adjustable back angle. to help us maintain a slightly backward posture and reduce spinal pressure.

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. According to the body pressure distribution curve, these two small ischial bones bear more than 75% of the weight of the upper body, with the rest on the buttocks and thighs.

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, and there are a large number of blood vessels and nervous system at the bottom of the thigh, which will affect blood circulation and nerve conduction, leading to numbness, edema and other problems.

At the same time, if the sitting surface is too soft and sinks a lot, the inappropriate height of the armrest will increase the pressure on the elbows and shoulders, resulting in shoulder and neck pain.

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.

Therefore, for sedentary people, a suitable ergonomic chair is very necessary.

However, The biggest difficulty in buying an ergonomic chair 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?

The more comfortable a chair is, the more complex it is in engineering. Today's ergonomic chairs include at least eight modules: castor, five-star feet, gaslift, mechenism, seat, armrest, and headrest. So now  we will start with these 8 modules.

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 foundation is not solid, the earth shakes", the force on the buttocks is uneven, the pelvis is not correct, and the curvature of the sacrum is not correct. the curvature of the lumbar, thoracic and cervical vertebrae above the sacrum is even less likely to be correct, and there is no comfort to speak of.

The seat needs to pay attention to two properties: the material and the seat area.

(1) material.

The material is related to the elasticity (comfort), durability, and cost of the chair surface: the greater the elasticity, the stronger the support, the more comfortable the sitting feeling; the stronger the durability, the longer the service life; the better the material, especially the imported special mesh , the more expensive.
The material can be divided into two kinds: mesh c and sponge, among which, the mesh material is more breathable and is commonly used all the year round, and the sponge cushion will be very uncomfortable in summer.

(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 , such as the most expensive matrex mesh  in the United States and wintex mesh in South Korea. 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. 

However, although some ergonomic chairs use the same kind of mesh, the elasticity and sitting feeling of the feedback are still slightly different.
This involves another key factor in the seat-zoning.

(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.

In view of this imbalance of pressure distribution, 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. the tension of the front-end and back-end partial pressure area should be the largest.

2. Chair back: spine Guardian

The back of the ergonomic 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.

At present, the mainstream chair back in the market is divided into single-back design and double-back design, if further subdivided according to the waist, can be divided into: no waist or fixed waist single back, independently adjustable waist single back, adaptive waist double back, lumbar sacrum double support waist chair back, these four kinds.

(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.

It should be noted that the single back of the advanced class and the double back of the middle and high end are not absolutely good or bad, and you need to consider your weight and spinal health when choosing.

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).

But it should be noted that the partition interval between the upper back and the lower back should not be too large.

In addition, as long as you are not overweight, there is no problem with the lumbar spine, you can use a single back + independent adjustable waist support, it is easier to find a suitable waist support position when sitting.

(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 °. If you need a lunch break, the larger the back angle, the better, generally 126 °~ 130 °, with a maximum of 160 °.

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 chairs must provide back adjustment.

There are two kinds of adjustment, one is adaptive elasticity according to the user's weight, the advantage is low failure rate, and the disadvantage is that the actual experience of small weight people is not friendly, so it is more recommended to adjust the elasticity of the chair through the knob on the mechanism.

3. Mechanism: adapt to the change of sitting posture.

Under normal circumstances, our sitting posture cannot remain the same. In order to adapt to the change of sitting posture and play a supporting role all the time, all parts of the ergonomic chair need to respond quickly, so the faster the adjustment, the better, and the simpler the operation, the better.

The adjustment operation of the ergonomic chair is integrated on the mechanism, and the quality and type of the mechanism directly determine the ergonomic characteristics, which is also the most test part of the manufacturer's manufacturing ability.

(entry level)the entry-level mechanism is a single torsion spring design, which belongs to the public model, that is, there is no independent design, and the same mechanism is used at the same level. It is mostly used in cheap ergonomic chairs, and can only adjust the gaslift and locking angle. Leaning back and sitting all depends on the strength of your own abdominal muscles.

(Middle level) the mechanism of the middle level is a single spring design, which also belongs to the public model. Compare to the entry level, it can adjust the strength of the back of the chair, which is mostly used in middle level ergonomic chairs  but because of the characteristics of the spring itself, the strength of leaning back is small at first and then big, and people with less weight may not be able to hold it down behind.

(middle to high level) the middle to high level mechanism is a double-spring design, and the design of each brand is different. Compare to the middle level mechanism, it can provide more operations, such as adjusting the backward strength of the rocker, adjusting the seat depth, and integrating more operations on the same knob, but the disadvantages are the same as the middle level

[high-end] the top mechanism  adopts double glass fiber design, which solves the problem of uneven spring adjustment and is more durable.

4. 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.

5. 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.

6. Gaslift, five-star foot, castor

Many articles writing about gaslift and chair feet separately, it is true that they may do not know much about ergonomic chair industry, and these three parts of technology are already too mature, not to mention ergonomic chairs, which are very basic, the more basic it is, the harder it is to go wrong.

Factors that can not be ignored: height and weight.

If you choose the top ergonomic chair within your budget according to the above selection and purchase method, will everything be fine and you can place an order directly?
Of course not!

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.

 weight.

If you are overweight, obese, weight 80kg or above, first consider the ergonomic chair with high-density sponge cushion. If you are afraid of boredom, you should at least choose the ergonomic chair with American matrex or South Korean wintex mesh , but it may press your legs a little bit. In this case, do not buy a chair with cheap nylon mesh , which will not take long to fall into shape.

For low-weight people (below 50kg) and overweight and obese people, don't buy an ergonomic chair with a lean back, that is, a chair with a single torsion spring mechanism, because you probably can't lean back or lie down and get up.

Height.

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, and the legs will go numb over a long time. 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:

In other words, male compatriots with height 169cm should choose ergonomic 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.