The consequences of poor seating
Research has revealed that backache is one of the major health factors influencing a person's work performance and is responsible for a large percentage of lost working days. It is commonly known that pain makes a person tired and can significantly interfere with a person's quality of life and general functioning. Experts estimate that we spend up to 80 000 hours seated the consequence of which can be: tension, headaches, backache, impaired digestion and concentration. Poor posture places tension in various parts of the body and reduces ones breathing capacity significantly.
Research by Dauphin shows that a seat tilt of up to -12° (claimed to be a unique synchro feature in Dauphin's chairs) is ideal as it allows the position of the pelvis, when sitting, to be similar to its position when standing and this helps to minimise strain on the user's spinal column, thus creating the healthiest posture. Furthermore, this posture allows room for the lungs to expand to full capacity, which allows oxygen to flow freely to the brain and increase energy. Therefore, one way to potentially conquer tiredness is to address bad seating habits and ensure that you have a chair that is ergonomically sound.
1. Traditional type office chairs were not designed with the human body's movements in mind whereas ergonomic chairs are designed to work with the human body and give support where needed. The Dat-O chair which is claimed to be the first chair ever to be certified by ESSA is unique in that it can adjust to accommodate the user's specific height and weight and was praised by ESSA for taking into the account the human factor.
2. An ergonomic chair has multifunctional, height adjustable armrests that can be set to ensure your shoulders are completely relaxed when your arms are resting on the desk, taking the strain off your neck and shoulders. This ensures that there is no pain in these areas of the body and that you are well supported. Choosing an ergonomic office chair that supports your own posture can help to prevent injuries to the back and neck whilst improving your overall productivity and energy levels at the same time.
1. Always place your feet flat on the floor.
2. Always maintain contact with the backrest.
3. Correct your bearing if you slide forwards on the seat.
4. Avoid extreme bending to one side whilst seated.
5. Only reach down to objects near the floor by bending forwards over the legs.
6. Do not cross your legs when sitting forwards.
7. Practise active, dynamic sitting as often as possible.
8. Train an upright posture without backrest every now and then, provided the chair has an automatic seat tilt adjustment.
9. When standing up and sitting down, always bring the centre of gravity for the extended upper part of the body over your knees.
10. Perform regular exercise at your workplace.
How many hours did you spend sitting today? Even if you have an active lifestyle, sitting down is how most of us spend a good part of our day. Between driving, working at the computer and watching TV, experts estimate that we spend in excess of nine hours in the seated position. The consequences? Backache, headaches and neck pain.
People in the office environment are especially at risk. A new study by the Division of Physiotherapy at Stellenbosch University reveals that academics are exposed to up to 12 hours of computer work a day and that computer-related musculoskeletal pain is on the rise. Neck pain prevalence is as high as 77% and low back pain is roughly 45% among academic workers. The study found that the strongest predictors of musculoskeletal related pain among office workers include the duration and frequency of computer work, little variation between academic tasks, job strain, female gender, poor ergonomic workstation design and comfort of computer workstation.
While workstation design is one key area that can be addressed, investigations into people's sitting habits during workstation assessments have repeatedly shown that people do not sit in the ideal way. Yes, researchers have spent a great deal of time determining what the most healthy sitting positions are, but the recommended 'sitting norms' are unfortunately static, making it impossible for people to stick to them throughout the day.
Furthermore, according to one of Europe's leading ergonomic experts, Malte Lenkeit of the Dauphin HumanDesign Group, although any healthy person could claim that they sit correctly, the fact is that no two people sit the same way. A recent study that looked at the way people used office chairs confirms this.
It showed that a person's sitting habits are adopted during childhood as part of a formative process in much the same way that we learn to walk. Just as comfortable shoes play an important role in preventing fatigue when walking, a carefully adjusted chair plays an important role in ensuring employees have the freedom to sit in their own specific way.
So what is the best way to sit? Experts all agree that a 'dynamic seated posture' is desirable as it prevents one-sided strain being placed on the muscles. A recent field study carried out by Dr Fritz Andreas Scion and Dr Dieter Preim from the RWTH Aachen, Germany, shows that a dynamic seated posture requires both a specific degree of freedom and limits. They found that in addition to sweeping movements and changes in a seating position, which affect the strain on the spinal column, micro-movements play an important role too. If micro-movements are restricted, a balanced physical posture when sitting becomes impossible.
Another prerequisite for a balanced seated posture is a slight forward tilt of the pelvis, which takes the strain off it. Contrary to popular belief, the laid-back, slouched seat position is actually anatomically incorrect as it puts pressure on the spine. The ideal is a forward seat tilt of -12º because this mimics the position of the pelvis when standing and minimises strain on the spinal column.
One mechanism that allows dynamic movements is the Dauphin HumanDesign Group's Dat-O ergonomic chair. It enables regular spinal adjustments when in the seated position. With this in mind, the Division of Physiotherapy at Stellenbosch University conducted a study to determine the effectiveness of an individually-fitted Dauphin HumanDesign ergonomic chair on low back pain, neck pain, muscle tension as well as chair comfort among academic staff.
The subject was a 51-year-old professor who had chronic neck and low back pain. He perceived his spinal symptoms to be related to computer usage. The chair was individually adjusted to the subject using standard ergonomic criteria for matching a chair to the individual's anthropometry. The study was conducted over a period of seven weeks. It consisted of two phases - the baseline phase when the subject sat on his usual office chair and an intervention phase where the subject was required to use the ergonomic chair.
The findings showed that the chair had a positive effect on all symptoms except for neck pain intensity. Low back pain intensity and frequency decreased, neck pain frequency decreased, neck muscle tension frequency and intensity decreased and chair comfort increased. Although this study was conducted on only one subject, the initial findings are important and demonstrate that further research in this area would be useful. Currently Rhodes University together with Dauphin are working on a project to demonstrate not only the health benefits to the user of ergonomically sound chairs but also to demonstrate the financial benefits that are gained through improved productivity.
'Dynamic movement is key,' says Debbie Arnoldi-Radford, MD of Dauphin HumanDesign Group (South Africa). Our bodies are better designed to be on the move, than to spend long periods of time in the same position. Movement is therefore a decisive factor in the fight against the typical complaints for seated employees.'
Arnoldi-Radford also points out that in addition to having the right chair, anyone can achieve noticeable improvement simply by changing certain habits at their desks.
Andrew Todd, Lecturer at Rhodes University Department of Human Kinetics and Ergonomics and chairman of the Ergonomics Society of South Africa (ESSA) agrees.
'In addition to finding the right match between chair and desk and their own physical characteristics, workers should incorporate appropriate rest breaks. These breaks should be short and frequent and involve movement, for example alternating between sitting (60% of your day), standing (30%) and walking (10%) two to four times and hour. This will relieve the contraction of the back and neck muscles, stimulate activity in the extremities, the heart and improve blood circulation. As a rule, five minutes of active stretching and training of the back musculature each day is better than half an hour once a week.'
Ensuring comfort in the seated work environments requires two important factors to which one should adhere. Firstly that the office environment is ergonomically sound, with compatibility between the anthropometric characteristics of the user and the office environment. However, the maintenance of a static posture (no matter how ergonomically sound) will ultimately lead to fatigue. Consequently the inclusion of a chair that has adjustability as a key feature coupled with frequent changes in position is imperative for optimal workspace design. This will hopefully ensure not only that the user is more comfortable and healthy but also that they are more productive, thereby helping not only the individual but also the business they work for.
Visitors to the Dauphin HumanDesign Group's Johannesburg and Cape Town showrooms can get the low-down on their seating habits from the group's two technologically advanced measuring tools - ErgoMouse and the Eyeseat. Pioneered by their European parent company, the tools extract data relating to employee's seating habits and help individuals make smart seating choices.
For more advice and information on sitting correctly, call the Dauphin HumanDesign Group on +27 (0) 11 447 9888 or +27 (0) 21 448 3682.
The ErgoMouse is a measuring device for optically displaying seated-posture profiles. The small, inconspicuous device is used within the workplace in conjunction with a PC and a printer.
What is an Eyeseat - the Intelligent Seat-Analysis System?
An Eyeseat has four pressure sensors in the seat and two pressure sensors in the backrest that show the way in which the user is sitting on the chair and their various postures. For example, if the worker spends a relatively long period of time sitting on the front edge of the seat, or without making contact with the backrest, a message reminding them of the need to correct their posture is shown on their PC monitor. Electronic operating instructions round off this option.
The eyeseat registers the workers' seated postures and documents them. Their behavioural patterns are shown on the monitor and suggestions for improvements are given where necessary, ultimately with a view to achieving a change in seated behaviour.
The key functions of this system are to ensure that the user achieves a balanced seated posture by alternating between movement and rest and that the chair is adjusted correctly and full use is made of its features.
