Ergonomics, the study of people’s efficiency in their work environments, has become widely accepted as a way to prevent injury and discomfort in the workplace. Since many of us spend anywhere from 40 to 60 hours on average per week working, the science of ergonomics can help us modify the tools and equipment we use on a daily basis to ensure optimum comfort and maximum effectiveness.
To work in many business and office environments, it is necessary to sit at a desk or computer for long periods of time. Sitting in one position for any length of time stresses the spine, which can cause poor posture and back problems. Many companies are adopting ergonomic practices and purchasing ergonomic furniture, like office chairs, to prevent injury from occurring.
Because people not only come in all shapes and sizes, but also work in a variety of different ways, even when performing the same task, no one type of chair can be called the best ergonomically. However, there are certain features that should be included in order to make the chair adjustable for each person who will be using the chair.
Features of a Good Ergonomic Chair
The goal of an ergonomic office chair is to reduce fatigue, minimize repetitive strain and improve productivity. The simple rule of ergonomics is to make it comfortable and the more controls that are included, the more adjustable the chair will be to a specific person’s body shape and height. The height of the backrest, the depth and width of the seat, the seat’s angle and the armrests should all be adjustable to allow the individual user to modify the chair to his or her own ergonomic needs.
When a person sits in a low back office chair, he or she should be able to sit in a relaxed upright position with both feet flat on the floor, thighs horizontal and arms level with the desk. For a person of average height, this means that from the seat to the floor, the height of the seat pan will range from 16 to 21 inches. The seat lift makes the seat pan adjustable, so that the chair can be positioned correctly.
Ideally, the width of the seat will be wide enough to allow for a 1” space on either side while a person is sitting. This will mean that for a person of average height, the seat should be 17” to 20” wide. To ensure proper circulation, the seat should have a rounded or waterfall edge, which means that it will slope slightly downward to help relieve pressure on the back of the thighs.
The seat pan should be deep enough to allow 2” to 4” of space between the back of the knees and the edge of the chair when the torso rests against the backrest and the feet are flat on the floor. To be able to change the seat’s depth, purchase a leather office chair with a sliding seat pan control; this will allow you to adjust the depth of seat from front to back. For additional adjustability, the angle of the seat pan can be modified, reducing pressure on the spine and legs.
The chair tilt control shifts the angle of the entire seat pan in relation to the floor. A properly tilted chair will position the upper body properly against the chair’s backrest. Chair tilt can be one of two types, column tilt or knee tilt. A chair using column tilt pivots on the top of a post, while the user lifts their knees to make the backrest slant downward. A chair using knee tilt pivots from a point in front of the post near a person’s knees. The knee lift control is limited in comparison to a column tilt, but will slant the back of the seat down further than the column tilt style.
An office chair’s built-in lumbar support is designed to match the natural curves of the human back. Adjustable controls that manipulate the back of the chair into the proper position are important to maintaining the back’s center of gravity. Since the spine naturally curves inward, a high back ergonomic chair must support this part of the back. Sitting for long periods of time without supporting the lumbar curve can cause slouching or contribute to the flattening of the discs and other musculoskeletal disorders. The lumbar depth control changes the curve of chair so that it can be made to correspond to a particular person’s lumbar region.
The height of the backrest will determine how well your back is supported while sitting in the chair and should be 12” to 19” wide. It must support the person without pulling them forward or pushing them back when seated. The backrest of a mid-back ergonomic chair will have built-in or add-on lumbar support that can be adjusted, including a locking mechanism to prevent it from going too far back. Whether the backrest is separate from the seat or if the back and seat are joined together, the backrest should be adjustable.
A person sitting in an office chair where the arm rests are too high, might experience stress or discomfort in the back of the neck, elbows and forearms due to the shoulders being forced into a “shrugging” position. To sit in a chair with armrests that are too low, a person must lean over or to one side to get comfortable. Whether the chair arms are too high or too low, not sitting properly for extended periods of time will decrease personal comfort level and affect work efficiency. Height-adjustable armrests will let the user position the chair arms according to their requirements and/or the tasks being performed at any particular time. Width-adjustable armrests vary the distance between the armrests. If the chair arms are too far away from the torso, it can cause misalignment of the elbows, making the wrists bend to side in order to compensate.
What Else Should I Keep In Mind When Choosing an Ergonomic Chair?
While the number of adjustable controls is an important consideration, the quality of construction and the materials used should also be taken into account. Padding should be thick, “cushiony” and long-lasting. A fabric office chair that offers support and is comfortable at the same time promotes good posture.
A large number of office chairs are designed for the person of an average height and weight range. If a person cannot sit comfortably in the seat pan with space to spare on either side, even after the chair has been adjusted, they might need one designed specifically for larger body types such as a big & tall office chair.
If, after adjusting the height and angle of the ergonomic office chair as much as it can be, the user may still need to use a footrest in order to sit comfortably upright.
The chair’s controls should be easy to reach and use while the person sits in the chair. Adjustment controls are either mechanical or pneumatic: pneumatic office chairs, based on a system of springs and compressed air, are considered to be more user-friendly.
A 24-hour task office chair ergonomic chair is only half the story. To take full advantage of the benefits of ergonomic office chairs, ensure that workstations have been set up according to ergonomic principles.