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What are the parts of an ergonomic office chair?
Knowing the parts of an ergonomic office chair helps you better understand how it works, which adjustments you need and which component may be failing if the chair stops being comfortable.
An ergonomic chair is not set apart simply by having wheels, armrests or a high backrest. The key lies in how its parts combine to adapt to the body: seat height, lumbar support, backrest tilt, arm position, base stability and wheel mobility.
In this guide we review the main parts of an ergonomic chair, what each one is for and what you should check if you are comparing models. And if, beyond identifying each component, you want to know how to assess a complete purchase, you can find more information in our guide to choosing an ergonomic chair.
Article index
Head support, headrest or neck rest
The headrest is the upper part of the chair. Its main function is to support the cervical area, especially when you recline, take breaks or work for many hours in front of the computer.
Not all ergonomic chairs need a headrest, but if it includes one, it is advisable for this part to be adjustable. Ideally, it should be adjustable in height and, if possible, also in tilt.
This way, the support does not push the head forward or force the neck into an uncomfortable posture. When checking this part, make sure the headrest follows the natural movement of the head and does not sit too high or too low.
For users who tend to alternate work and rest in the same chair, it can be an interesting extra.
Backrest
The backrest is one of the most important parts of any ergonomic office chair. It is the part that supports the back and helps maintain a more stable posture throughout the day.
A good backrest should follow the natural curve of the spine, offer enough support in the dorsal area and allow some movement. In ergonomic chairs, it is common to find backrests made of breathable mesh, technical upholstery or mixed structures with reinforcement in the lumbar area.
It is also worth checking whether the backrest lets you adjust the tilt or secure different positions. It is not about always sitting completely upright, but about being able to change your posture slightly without losing support.
Within the backrest, the lumbar support deserves a special mention. This part helps hold the lower back and can make a big difference if you spend several hours seated. Ideally, it should be adjustable in height or depth to adapt to your body.
If you are looking for freshness and breathability, you can consider mesh office chair models, especially for warm spaces or long working days.
Armrests
Armrests help relieve tension in the shoulders, arms and neck. To do their job well, they should let the elbows rest naturally and keep the shoulders relaxed.
In an ergonomic chair, it is most advisable for the armrests to be height-adjustable. Some models also let you adjust the width, depth or rotation, which is known as 2D, 3D or 4D armrests.
A common mistake is to think that any armrest improves posture. If they sit too high, they can raise the shoulders. If they sit too low, they barely offer support. And if they hit the desk, they can force you to sit too far from it.
That is why, when comparing an office chair with armrests, it is not enough to check that it has them: it is worth reviewing what type of adjustment they offer and whether they adapt to your height and your desk.
Seat
The seat is the surface that bears the weight of the body, so it directly influences daily comfort. It should have enough width, firm padding and an appropriate depth.
A seat that is too short can leave part of the thighs unsupported. One that is too deep can press the back of the knees or prevent you from resting your back properly against the backrest.
As a reference, when you sit down there should be a small space between the edge of the seat and the back of the knees. The type of foam is also important. In higher-quality models, injected foam tends to offer greater resistance to continuous use and keeps its shape better over time.
If the chair is going to be used many hours a day, an adjustable seat depth is a very interesting point, especially when the chair will be used by people of different heights.
Lever mechanism
The mechanism located under the seat is the system that lets you adjust the chair. In the simplest models it usually controls the height. In more complete ergonomic chairs, it can also manage the backrest tilt, the rocking, the tension or the locking in different positions.
This part is key because it connects comfort with movement. An ergonomic chair should not force you to stay still, but rather allow small changes of posture during the day.
There are different types of mechanisms: tilting, synchronised, permanent contact or systems with tension adjustment. If you want to go deeper into this technical part, you can consult the guide on types of mechanisms for office chairs.
Before buying, check that the controls are accessible from the seated position and that the mechanism suits the use you are going to give the chair. For long working days, a system that lets you recline and secure the backrest comfortably is usually preferable.
Gas piston
The gas piston, also called a pneumatic cylinder, is the part that lets you raise or lower the chair. It sits between the seat mechanism and the base, and bears a good part of the user's weight.
When the piston works correctly, the chair holds the chosen height steadily. If it is damaged or worn, the chair may lower on its own little by little, even without operating the lever.
This component usually goes unnoticed until it fails, but it is essential for properly adjusting the height relative to the desk. If you cannot adjust the chair to the right height, it is easier to end up with raised shoulders, unsupported feet or a poorly placed back.
If you have this problem, you can review the article on why your chair lowers on its own before replacing the whole chair.
Base
The base is the lower structure that provides stability. In most office chairs it has the shape of a five-spoke star, because this distribution helps spread the weight better and reduces the risk of tipping over.
It can be made of polyamide, aluminium, steel or other resistant materials. The choice of material influences durability, the weight of the chair and the sense of stability.
A sturdy base is especially important in chairs used for many hours, in models with a reclining backrest or for users who need a chair with greater carrying capacity.
It is also worth checking that the base is compatible with the type of wheels of the chair and with the floor where it will be used. Moving on carpet is not the same as moving on parquet, tile or laminate flooring.
Wheels
The wheels let you move the chair without getting up and make small movements easier while working. Although they seem a simple part, they greatly influence comfort and the care of the floor.
The type of wheel should be chosen according to the surface. Some are more suitable for hard floors, while others work better on carpet. If the wheel is not suitable, it can slide too much, jam or even scratch the flooring.
It is also important to clean them from time to time, because they accumulate dust, hair and small particles that can hinder movement. To expand on this part, you can read the guide on types of wheels for office chairs.
Conclusion: which parts you should check before choosing an ergonomic chair
The most important parts of an ergonomic office chair are the backrest, the lumbar support, the seat, the armrests, the adjustment mechanism, the piston, the base and the wheels. They all fulfil a specific function, but the important thing is that they work together to adapt to your body and the way you work.
Before choosing a model, check these key points:
- ✓Adjustable height: check that the chair can be adjusted correctly relative to the desk.
- ✓Backrest with good support: check that it follows the back and helps maintain a stable posture.
- ✓Suitable seat: assess whether it has a comfortable depth to support the thighs well.
- ✓Adjustable armrests: make sure they do not raise the shoulders or hit the desk.
- ✓Stable base: confirm that it offers safety and strength for daily use.
- ✓Appropriate wheels: choose wheels compatible with the type of floor where you are going to use the chair.
If you already know which components you need and want to compare models designed to work, study or work from home more comfortably, you can see our selection of ergonomic chairs for working comfortably.
