Effects of Sitting
While most of us believe it to be relaxing, sitting is actually the opposite. It increases strain in our backs because it transfers the full weight of our upper body onto our buttocks and thighs.
Sitting, especially for long periods of time, can also cause increased pressure on our intervertebral discs, which are the springy, shock-absorbing parts of the spine. It can also put strain on our lower extremities, this is because gravity pools blood in the legs and feet, creating a sluggish return of blood to the heart.
As most of us do not adopt a good posture while sitting, we exacerbate the problems. Poor sitting posture can not only cause physical discomfort it also contributes to serious health problems, including (but not exclusively):
• Back pain
• Neck pain
• Eye strain
• Abdominal pain
• Leg pain
• Repetitive movement disorders
Good posture combined with a well-constructed ergonomic chair can help reduce fatigue and discomfort, increase blood flow, reduce the risk of injury, and even increase productivity.
What is an Ergonomic Chair?
Many chair manufacturers use the word “ergonomic” to describe their products, however you might need to look further than the label to see if it truly incorporates ergonomic guidelines.
Whether a chair is to be used at a computer workstation or in front of a machine on the factory floor, it must be appropriate for the task and must fit your size and needs.
The recommendations below can help you when selecting an ergonomic chair and its optional extras, to help improve your posture, increase your comfort and reduce your risk of injury:
Casters are the pivoting roller or wheel attached to the bottom of the chair. Using a chair with casters and a 5-point base can make movement easier and help to minimize the risk of tipping.
There are multiple types of casters:
Hard Floor Casters: These are usually standard, working best with many hard floor surfaces.
Soft Floor Casters: These are normally used with carpeted floors, e.g., offices or home use.
Weight/Brake Loaded Casters: These are used to prevent movement when in use. These castors will move around like standard castors, however when your body weight is applied, they will lock and stop movement.
Glides: These are usually blocks/feet which fit to the star base of your chair. They are stationary and do not have wheels, this means if you have a tall chair such as a draughtman’s chair, you are less likely to fall off.
The seat pad is the element of the chair which supports the majority of your weight. Choosing a seat pad with a cushion made from good quality foam and materials helps to ensure good support and lengthen the life of your chair. Inferior cushions can: loose shape, compress, can cause discomfort, imbalance, hip and back fatigue, leg pains or more.
The dimensions of the seat pad are also important. When thinking about the width, you should look for around 2.5cm wider than your hips and thighs on either side, but not going more than 5cm as the chair will then be too large. You should also consider the depth of the seat pad, the front part of the seat should not touch the back of your calf/knees, there should be a 4cm or 5cm space between the end of the seat pad and the back of your knee/calf. This space allows for added comfort and helps to reduce pressure on your legs.
Seat pad tilt adjustments, can allow you to achieve an improved working posture. A seat pad which can adjust to positive and negative angle, can help alleviate pressure on your hips, back and legs. If a sliding mechanism is also fitted to the seat pad, this allows small and tall users to adjust the distance of the seat pad from the backrest, when the chair is being used by more than one person.
Backrests are key for providing lumbar support. Inadequate lumbar support can place excess pressure on the spine. You should ensure the backrest is large enough to provide support for the relevant areas of your back, lumbar, mid-back and upper back are all important to consider.
The backrest should ideally curve with the back to provide adequate support. Many chairs come with additional built-in lumbar adjustment, these can have a range of working mechanisms, from tensioning to air support sells. Easily adjusted, these can be used to help fine tune the chair to your needs.
Adjustable height and width are great to help get a better fit when purchasing a chair with armrests. There are many styles of arm rests available with different support qualities. The main styles include:
• Fixed armrests
• Foldback armrests
• 3D armrests
• 4D armrests
• 5D (multi-dynamic) armrests
• Support armrests
Almost all ergonomic chairs will incorporate some type of seat height adjustment, it is frequently a gas stem operated by a lever. This is one of the most import adjustment mechanisms on your chair.
Height adjustment allows you to correctly adjust your chair to your workstation height. Sometimes your feet may not reach the floor after these adjustments, so to rest your feet correctly, a footrest could be needed.
Resting your feet flat on the floor or on a footrest, while your upper body is correctly aligned with your workstation equipment, such as a computer display monitor, or keyboard. Helps you to create a better posture at your workstation, while reducing the pressure on your legs.
While gas stems are often operated by a lever and increasing or reducing pressure to adjust the seat pad height, it is possible to have a chair fitted with electronic lifting systems if you need this support feature.
Chair Movement Mechanisms
The chair ‘synchro’ mechanisms can change the angle of the entire seat, relative to the floor, while not compromising your workstation comfort; the chair will move with you as you move and continue to provide continued support.
Footrests – in some cases you may need to use a footrest. If you need a footrest, be sure to choose one appropriate for your needs, there are fixed height, adjustable height, standing and seated footrests available. Using a footrest will help reduce pressure on the base of your legs.
Fabric– when choosing a chair, keep in mind cleaning and maintenance of your chair over time. Cloth upholstery is the most common covering but may not be the easiest to keep clean. Vinyl covers are easier to clean often providing a peace of mind to uses with incontinence or medical issues.
Foot ring – If you are seated at height, a foot ring is essential for helping you safely mount and dismount the chair.
Head rests – contrary to the suggestion of the name, head rests or neck rolls are not usually designed to be used for long period of time. They are often added to a chair if you have a medical need for them or to provide you with extra support when you are reclining in your chair. If you spend time sat back in your chair on the phone, a head rest or neck roll can help reduce strain on your neck.
Movement Lock – If you would prefer your chair to have the benefit of a brake to reduce movement but still have the benefits of castor movement, this is your answer. Using a movement lock will allow to control when the chair can move and when it is held in a stationary position.
In addition to using a chair which allows you to sit with good posture, there are other precautions you can take to help minimize your discomfort while sitting:
• Don’t stay in one position for prolonged periods of time. Alternate between sitting and standing, when possible.
• Make sure your feet are flat on the floor or a footrest.
• Sit upright with your back and shoulders against the backrest, not slouched or leaning forwards.
• Do not use the armrests to slouch. Elbows and lower arms should rest lightly to avoid circulatory problems or nerve pressure.
• Make sure your shoulders are relaxed and slightly dropped while typing. Maintain a “neutral” posture:
• Your hips should be slightly higher than your knees.
• Your back should be fully supported and straight.
• 3 to 5 centimetres between the edge of the chair and the back of the knees.
• Equal distribution of weight on the seat cushion.
• Keeping your chair in line with your workstation, to reduce twisting or misaligned working.
Be aware of your posture during your working/studying time, it is important to take frequent breaks, stand up, stretch, take a few deep breaths, have short walk; this can help increase your blood flow and reduce fatigue.
Reposition yourself if you find you are slouching or moving out of the correct position; small adjustments like these can go a long way to keeping yourself comfortable and healthy, they can also help you maintain a better posture for a longer period of time.