A guide to office chair ergonomics.
Office equipment is expensive. Office chairs, computers, keyboards, mice, desks, and lights. They all add up. At times it may seem as though the term ‘ergonomic’ can make the price of an item jump by 20% (if you have ever bought women’s clothing or women’s specific athletic equipment, you know what I mean). At times, the term ergonomic seems to be synonymous with more expensive. However, proper office equipment’s payoff or return on investment is worth the cost.
If you are a small business owner or self-employed spending thousands of dollars on office equipment may not be an option. However, you also want to get the most out of your employees, or yourself as a worker without having to be responsible for additional medical bills, or a workers’ compensation claim. So what do you do? Spend the bare minimum on a bunch of inexpensive, and cheaply made items? What if they start to fall apart within months of someone using them? Do you instead spend the money on one piece of equipment that is of good quality? If so, which piece of equipment do you purchase?
The answer: a chair
Spend the money on a good chair. Why? Office chair ergonomics is important. The majority of desk workers do their jobs while sitting. Even workers who alternate between sitting and standing tend to spend more time in a sitting position as opposed to a standing one. A good office chair will support the user’s back, and decrease the risk of suffering from back issues. A good chair will also allow for adequate support of the legs, and decrease the risk of leg strain from sitting.
Compared to other office equipment, a chair can be the most expensive. However, the cost of a good office chair is an investment in employees and their work. A good office chair is often one that is adjustable. Being able to adjust an office chair is crucial, especially if employees are working from a fixed height surface. The ability to adjust a chair is also key if different employees share the same chair.
What makes a perfect chair?
When selecting an office chair, there are certain characteristics to keep in mind. While adjustability is key, one should also consider the user’s work tasks.
One should be able to adjust the height of the chair, as well as the depth of the seat pan. The chair should also be wide enough so that the user’s hips fit comfortably in the chair. The backrest of the chair should be high enough to support the user as they perform their work tasks. The need for additional features such as the ability to adjust the tilt of the chair, and armrests may depend on the user’s work tasks. Let’s take a look at office chair ergonomics.
Height
The chair height should be so that the angle between the user’s hips and torso is between 90-110 degrees. The exact angle between the torso and hips within that range depends on the user’s comfort.
Having a height-adjustable chair allows the user to adjust the chair to a height that is the most comfortable for them. Additionally, a chair can be raised so that smaller users can work at a fixed-height desk with their arms in a more neutral position. A footrest can help to support the user’s feet if the feet do not touch the floor in a higher position.
Seat pan depth
The seat pan depth is the measurement from the front of the seat pan (the part of the chair that you sit on) to the back of the seat pan. When sitting with the hip all the way in the back of the chair, there should be about 2-4 inches of space (or 2-3 finger widths) between the front of the seat pan and the back of the user’s legs.
Having some space between the front of the seat pan and the back of the user’s legs is crucial. Contact pressure on the back of the legs can affect the circulation of blood in the legs. If the circulation of blood to the legs is disrupted, the user may be at risk of developing an injury to the legs, or feet.
Seat tilt
Some office chairs have a feature that allows the chair to tilt forwards, and backward slightly. This feature may not be necessary for all users, but some people may find it more comfortable. Users who perform tasks where they are using the keyboard such as data entry, or writing reports may prefer to have the chair tilted forward slightly. Other users who perform tasks such as reading information on a computer screen, or talking in meetings may prefer to have the chair tilted back slightly. Users who perform both types of tasks may prefer to have a chair that is tilt adjustable as they can adjust the tilt depending on the task that they are performing.
Armrests
Whether or not to purchase a chair with armrests depends on the user’s work tasks. Armrests are intended to be used to rest one’s arms while they are meeting with others, speaking on the phone, or reading something on their computer screen. Armrests are not intended to be used to rest the arms while one is typing on the computer.
Casters
Casters are the wheels at the bottom of the chairs. While having a chair with casters may not be necessary for everyone, a chair with casters is easier to use. Casters allow the chair to roll. This can make moving the chair much easier (both on the user and the surface of the floor).
Some office chairs have the option of different-sized casters. In general, smaller casters tend to work better on hard surfaces such as tile or wood. Larger casters tend to work better on carpets, or rugs. Larger casters tend to work better on higher pile carpets than smaller casters. If the chair only has casters of a certain size that does not roll easily on a carpet, one may opt to use a plastic runner.
Chair material and upholstery
This may seem obvious, but the seat cushion of the chair should be comfortable to sit in. The material should also be breathable. If the user is performing work tasks in an area where infection control is a concern (such as a laboratory, or healthcare facility), the chair material should be easy to clean.
Other types of chairs
As an ergonomist and physical therapist, I get a lot of questions regarding chairs. One type of “chair” that I get asked about the most office is an exercise ball. While sitting on an exercise ball forces you to use more core muscles, it provides little in the way of postural support. An exercise ball is great to sit on for about 20 minutes before one starts to get tired and slouch. If one decides that they want to work while sitting on an exercise ball, I strongly suggest having another chair available.
There are also other types of office chairs. Some look like stools, but tilt. Others require the user to work in a kneeling position. There are others that allow the user to fully recline. These types of chairs may be great for some people but are probably not the right chair for most people.
The bottom line: a good base is important
Office chairs are important. A good base is everything. The pyramids weren’t built from the top down, they were built from the base up. A good office chair can provide one with a good base, or foundation for an ergonomic setup. A good ergonomic office chair is adjustable. Some chair features may depend on the user’s work tasks. Once you have a good foundation, many other things will fall into place. An excellent office chair can help to prevent injury.
Resources:
- A purchasing guide for office furniture from OSHA
- A guide to office chair components from OSHA
- A guide to selecting an ergonomic chair from the Canadian Centre for Occupational Health and Safety
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