Finding the right "ergonomic" chair is a common problem especially for people who want to purchase new equipment to make workstations safer and healthier places.
Ergonomic chairs are designed to suit a range of people; however, there is no guarantee that they will suit any one person in particular. For example, a chair could be too high and the arm rests too far apart for a short, slim person. In addition, chairs may not suit every task or arrangement at the workstation. A chair becomes ergonomic only when it specifically suits a worker's size (body dimensions), his or her particular workstation, and the tasks that must be performed there.
Today, in industrialized countries, many people sit for most of the time that they are awake. They sit while having breakfast, while going to work in cars or buses, in school classrooms, in meetings, in offices, during dinner, and at home while watching television. Many people also sit at work operating machines which new technology has developed to replace manual work. Although sitting requires less physical effort than standing or walking it puts a lot of stress on lumbar area. Combined effects of a sedentary lifestyle and a job that requires sitting can lead to many health problems.
The selection of a suitable chair is a critical step in preventing health problems in people who work in a sitting position. With the ergonomics approach, sitting is viewed as a specific, specialized activity which is influenced by the way that a sitting person interacts with the working environment.
Several basic concepts should be considered:
One chair does not fit everyone. The users' body dimensions must be used when selecting a chair so that it does not strain one part of the body while fitting another.
Collect data about the user's body height. The optimal seat height is about one quarter of the body height. This is only a rule of thumb since the torso-to-leg ratio can vary widely.
There is no chair suitable for every activity. For example, dentists require a different chair than do industrial workers or computer operators.
Consider maintenance and repair costs. Check with the manufacturer for items to inspect for and how often inspection should be done.
Some features are mandatory for a good chair regardless of how you intend to use it:
Adjustability - Check to see that seat height is adjustable.
Seat height range - Check whether the seat height can be adjusted to the height recommended for the worker(s) who will use it. Other chairs may have to be selected for very short or tall workers.
Backrest - Check to see that the backrest is adjustable both vertically and in the frontward and backward direction and has a firm lumbar support.
Seat depth - Select the seats that suit the tallest and the shortest users.
Stability - Check for the stability of the chair; a five-point base is recommended.
Other features to consider:
See if the selected chair has features that will help someone do their job better. Arm rests with adjustable heights are good for computer operators. Wider or narrower arm rests may also be required depending on the worker's dimensions and tasks they do.
See if the selected chair has features that will make doing a job more difficult. An example may be that someone may be using a chair with casters or wheels when a stable and stationary work position would be better. If chairs with casters are needed, choose ones that match the type of flooring you have (nylon casters for carpeting or urethane casters for hard floors).
A well-designed chair allows the user to sit in a balanced position. Buying an ergonomic chair is a good beginning but it may not bring the benefits expected. It is still important to sit properly. Also, remember that the chair is only one of the components to be considered in workstation design. All the elements such as the chair, footrest (if needed), work surface, document holders, task lighting and so on need to have flexibility and adjustability to be "designed in".
Many sources of information can indicate that your workplace can benefit from a good ergonomics program. Some 'triggers' that suggest that your workplace would benefit from an ergonomist’s services include the following:
Employees in your workplace, or in certain specific work areas, are experiencing soft-tissue injuries (STI), also known as Work-related Musculoskeletal Disorders or (WMSDs) such as tendonitis, back injuries, sore muscles, etc. These are all indicators that the job demands are excessive due to one or a combination of risk factors (i.e. force levels, work postures, repetitive actions, long durations, and/or psychosocial stressors).
High rates of general absenteeism and/or worker turnover. These can be indicators of high levels of physical or mental demand, poor workplace design, and/or poor organizational design.
High number of mistakes, and/or rework due to poor quality. These are often the result of difficult work processes, high workloads and fatigue, inadequate communication/information, poor visibility, etc. Poor, or declining, productivity over the course of a shift or over a series of shifts. This can also mean that the work is not well designed for workers.
Aside from detecting these triggers, you should consider the benefits to be gained from applying ergonomics proactively in order to prevent problems before they occur. This is the most effective and resource-efficient way to incorporate ergonomics into your workplace!
The goals of a comprehensive workplace ergonomics strategy include:
Improve individual and organizational productivity
Reduce errors and improve quality
Reduce systematic waste
Improve human and organizational performance, sustainability and well-being
An effective ergonomics process produces significant returns on investment across multiple business functions and metrics.
A general term for ergonomics in product and equipment design is usability. The more “usable” a product, the more “ergonomic” that product is. But it’s never that simple, and what may be ergonomic for one person, may not be for another. That’s why ergonomists apply a systematic, human-centered approach to design that considers at least three primary perspectives:
Who is the target user population, and what are the characteristics of that population? Depending on the product, those population characteristics might include age, experience, size (height, reach length, weight, etc.), strength, cognitive abilities, sensory abilities (vision, hearing, etc.), or any number of characteristics important to the particular design.
What is the intended use, as well as foreseeable uses and mis-uses, for the product? In other words, what tasks or activities will it be used in, and how will this product enhance performance, and protect the user from harm, while performing those tasks?
What is the intended environment of use, as well as other foreseeable environments of use? Will the product be operated indoors or out? Will it be wet or dry? What will the lighting be like? Will there be dirt, dust or other contaminants? And so on.
Ergonomists take a holistic design approach that balances product form and function to provide a fit that optimizes performance, under well understood usage scenarios, by a well understood population of target users. Products that undergo this human-centered, ergonomic design approach, are far more likely to achieve a positive user experience. Companies that deploy products that enhance user experience and performance are likely to meet with greater market success.
At the center of your office chair is the mechanism which interacts with you through different seating functions. Each individual has a unique, optimal comfort level when seated. Chair mechanisms are offered in a variety of designs which all provide a different degree of manual or automatic adjustment. The user should consider a pneumatic cylinder which gives you "finger-tip" seat height adjustment. Your daily work routine will help you to decide which style of mechanism is best suited to your needs.
There are three seating positions in the workplace pertaining to proper ergonomics.
Forward/Recline position – Dedicated tasks
Upright position – Dedicated tasks and multi-task
Backward/Recline position – Relaxed position
To Adjust An Ergonomic Chair
Stand in front of the chair.
Adjust the height so the highest point of the seat is just below the knee cap.
Your thighs should be parallel to the floor, when you sit.
This allows you to place your feet on the floor insuring good circulation in the legs.
Use a footrest if the feet cannot rest flat on the floor or if there is pressure underneath the thighs. The footrest should be adjustable and support the whole foot.
Sit so that the clearance between the front edge of the seat and the upper part of the legs behind the knee, is at least one finger width.
Adjust the back height to provide support to the lumbar or lower back area. This will help you to maintain correct posture and reduce back pain.
Adjust the seat angle by unlocking the mechanism to tilt the seat forward or rearward when working for extended periods of time. This minimizes pressure on the underside of the thighs and reduces tension on back muscles.
Adjust the back angle to provide firm support and help reduce back fatigue.
Adjust the optional armrest height to your comfort.
If using a fixed height work surface, raise the chair to obtain the proper arm and upper body position.
Adjust chair height so elbows are about the same height as the work surface.
Always follow the assembly directions completely. Make sure all the pieces are placed in proper order so that the chair stays tight and together.
Pay special attention to making sure the casters or wheels are fully inserted into the base of the unit.
Look for office chairs that have a 5-legged base.
Every 6 months or so, make sure all the parts of the chair are tightened to ensure stability.
Always keep the base of the chair completely on the floor.
Most office chairs are equipped with casters for use on carpeted surfaces. For other surfaces, speak to your retailer or manufacturer for appropriate custom selection.
Many office chairs are equipped with a tension control on the mechanism to compensate for different body weights. Always ensure that the control is properly adjusted, resulting in a smooth and controlled tilt motion.
Don't lean so far back in your chair that the wheels or legs lift up off the floor. Leaning can cause the chair to slip out from under you, cause structural damage, or can loosen important connections that can cause the chair to fall apart.
Never put all your weight at the very front edge of the chair. If you sit too far forward, the chair can tip over. Use a chair with a forward tilt mechanism if the task requires sitting in a forward position.
Don't leave electrical appliances on upholstered chairs. Fire can result if they overheat. Be careful when smoking cigarettes or carrying lighted material around upholstered chairs.
Don't overwork your chair. Chairs in medical institutions or in other locations that are used 24 hours a day, get three times the use of a normal office chair. Inspect and maintain those chairs at least every 60 days.