ERGONOMICS – INTRODUCTION
As a result of the computer technology and internet development, nowadays moreand more work is done by computer at home or in the office. Consequently, a working person of today is increasingly exposed to the negative effects of prolonged sitting.
A human body which is meant to move suffers due to its rigid posture in the process of mental work. Yet, the negative effects of prolonged sitting can be reduced by using ergonomic working/office chairs the proper lines of which help the body to maintain the relaxed and correct shape during intensive business situations.
PROLONGED STATIC SITTING
Prolonged static sitting is sitting in a hunched position and without the possibility of moving the body during work process. While sitting in this way we feel there is a shortage of support in the lumbar area of the spine while the pressure on the thoracic vertebrae is increased. Furthermore, a pain appears in the muscular area of the back, neck and shoulders, blood and lymphatic fluid circulation in this area is slowed down, which results in increased stress of the cardiovascular system in the body.
All of this does not only have an impact on diminished working abilities but causes serious health problems as well.
Spinal vertebrae are the largest system in a human body which does not contain blood vessels. Cartilage tissue is fed through the process of diffusion which depends on the pressure and moving. The absorption of fluids and nutrients, and excretion of harmful metabolites in spinal vertebrae depends on the degree of pressure on individual vertebrae. Static sitting in a hunched position increases this pressure, which inevitably leads to irregularities in their metabolism. Such sitting posture brings about an asymmetric increase of pressure on thoracic vertebrae, which in turn causes pains most frequently appearing in this area of the spine and injuries such as displacement of vertebrae or disc herniation.
ERGONOMIC OFFICE CHAIR
With its health-friendly parts, an ergonomic office chair enables the negative effects that prolonged static sitting has on health to be reduced.
Its shape and construction allow you to sit comfortably while working, it offers the necessary support to those parts of your body which are most exposed to the negative effects of prolonged sitting.
The back of the chair has been designed in such a way that it provides support in the lumbar area of the spine (areas 3 and 4 of the lumbar vertebrae); the latter are under most strain in the upright position and take over the majority of pressures when the position is changed: in this way it takes off the pressure of the spinal vertebrae and the lumbar area of the back.
The seating of the chair has been made in such a way that its shape enables a comfortable position of the lower part of the body and reduces to the highest degree the possibility of pains in the coccyx and hip area: these pains appear already after several hours of sitting.
The mechanism of the chair with its functions provides a solid support to the upper part of the body through the resistance the back of the chair offers to the chair user and thus prevents the feeling of the back of the chair/support giving; consequently, it makes the user decide to sit dynamically. Moreover, it enables the body to assume several positions during work: the former can be chosen by the user depending either on their wishes or on the nature of the work the user performs.
Arm-rests (arm supports) provide support to the arms during work process and take over a part of strain on the body thus relieving other parts of the body during work process. The additional option of adjusting the height, depth and rotation of the chair allows even a more remarkable adjustment to individual users and their respective work tasks; it prevents the hunched posture and enables the users to assume a correct posture behind their work table.
The adjustability of the height of the chair and the option of moving (casters) are just as important elements which a quality ergonomic chair cannot possibly go without.
CORRECT SITTING POSTURE
- Take advantage of anatomically shaped surface of the chair and define a constant contact between the back of the chair and your back so that you will be able to enjoy the ergonomic characteristics of the chair to the fullest.
- Do not fix the chair in a particular position. Leave it in a neutral position but adjust the resistance of the back of the chair taking into consideration your weight so that you can move/change the position of your body as easily as possible while working without, in doing so, losing concentration; what is most important, however, is that in this way you see to your healthy dynamic sitting posture.
- Adjust correctly the height of the chair and arm-rests, i.e., the 90° elbow angle and that the elbow bone (the ulna) is aligned with the plane of the working surface of the table. Also the angle of the legs under the seating should be 90° when the feet are flatly on the floor. If the working surface of the table is too high and cannot be lowered, a foot rest, adjustable by the height and the angle, will be needed.
- Regardless of how good and qualitative ergonomic chair you have you have to follow the rules of healthy and correct sitting. Failing this, the advantages of a good chair will not be enjoyed to the fullest. This is the only way of protecting your body to the largest possible extent, and maintaining your health by using a good ergonomic chair. Never forget that your health is priceless!
Part 1: ERGONOMICS
The word ergonomics derives from the Greek stems “ergon” meaning human work and strength “nomos” meaning laws or rules.
ERGONOMICS stands for the shaping and understanding of human work.
Contents-related definition of the concept:
ERGONOMICS is a scientific discipline concerned with the understanding of human physical and mental capabilities with respect to work, working environment and workloads. It studies the adaptability of work (tools, work tasks, workplace layouts) to the users and their needs and not vice versa, i.e., the users adapting to the needs of their work.
MYTHS AND FALLACIES ABOUT WORKPLACE
Many generally recognised rules on correct sitting and posture while working with a computer are actually fallacies. If we apply them consistently they can lead to unpleasant and costly mistakes.
Here are some of these myths and fallacies:
Correct posture while working with a computer prevents discomfort and the possibility of injuries. “Perfectly correct” posture can be explicitly strenuous and tiring. If you commute to work and sit for the larger part of your working hours, you spend 10 to 12 hours a day sitting. When you are sitting the upper part of your body carries the entire weight of gravitation, which ultimately leads to the fatigue that brings about the tension in your muscles and pains in your joints. The strain intensifies even more if you are sitting upright and do not use the back of the chair as a support.
Users should be sitting upright in front of their computers. If it is possible, 4 out of 5 workers will bend slightly while working since this is how they reduce muscular activity which is indispensable to keep the upright position.
The chairs with adjustable height allow work behind tables of various heights. In many cases the adjustment of the height of the chair does not have an impact on the correct posture while working at the table. If the working surface of the table is low, lowering the height of the chair will reduce the space for the knees and legs. This may lead to an uncomfortable position which increases even more the strain on the back. Persons who are small in stature working at a table of a standard height have problems frequently while working. If the seating is lifted to make the work more comfortable, the feet will hang loose above the floor. In such cases feet-rests provide a support; however, they cannot meet fully the requirements of the work. The best solution to avoiding incorrect postures is to adjust the table or change work tasks.
Ergonomic chairs have been shaped so that they can be adapted to all users. We are all different in stature; women have a somewhat wider pelvic area than men and need a chair with a higher lumbar support and larger seating. Men frequently have longer legs and they need deeper seating. When choosing a chair you need to follow your individual needs.
Do not be misled by similar rules at your workplace. Find out for yourself which position suits you best. Choose furniture and a chair which meet your needs and embrace good working habits. While working, often change your posture and take short breaks. Health at work? Simple logic can help you a great deal in pursuing this goal.
Part 2: THE PROBLEM
Frequent and prolonged periods we spend sitting at our working tables can have a sustainable harmful effect on our physical and mental health, which in turn brings about a negative effect on the quality of work.
Here are some statistical data:
During our lives, we spend sitting on average 80,000 hours – learning, studying as well as working.
The time we spend at our working tables is getting longer and longer, which means that the risk of the negative effects of prolonged sitting is getting more alarming as well.
If we take into consideration that over 65% of persons in offices assume incorrect sitting posture while working, it is obvious that something needs to be done. Urgently.
In order to solve the problems, it is not important only where we sit but mainly how we sit. One of the most critical discoveries in examining the ergonomics of work is a surprising, yet a clear fact that sitting requires a significant muscular activity. The sitting itself is not the problem; the problem is the activity of the muscular system which is under a lot of strain while we are sitting.
Dorsal muscles are primarily intended for the upright position of the spine. When the spine is in the normal upright position they can stand a considerable effort. However, under strain, when we bend (owing to weak muscles and incorrect posture), the spinal vertebrae and the spine itself undergo considerable wear and tear and get damaged. This leads to sustainable back pains and chronic degenerative injuries.
The supporting role of dorsal muscles is thus if immense importance. Unfortunately, the conditions of everyday work, the prolonged periods we spend sitting, lead to a permanent unhealthy strain on dorsal muscles, which can in turn cause muscle cramps. Other muscle groups are also under strain: for instance, when we lift our shoulders for an inch or two while typing, tensions may arise in the area of the neck and shoulders.
The result of the tension in dorsal muscles over a long period of time renders the support to the spine impossible. The spine is no longer shaped correctly, to wit, upright, it bends, which causes numerous negative effects such as pains in the back and in the loins, tensions in the area of the neck and shoulders, general feeling of not being well, diminished concentration and indigestion.
Part 3: ERGONOMIC SOLUTIONSS
The requirements related to dynamic sitting are only met by ergonomic office chairs which offer everything that is needed for healthy and tireless sitting. Ergonomic office chairs do not make their users to assume rigid and stiff postures, they enable them dynamic sitting and an excellent balance of the body. While we are sitting in an ergonomic office chair our bodies automatically assume the best possible position and at the same time take the strain off of the spine to the largest possible extent. Thus, not only do they prevent major injuries but increase the possibility of concentrated work without being tired as a consequence of sitting.
Specific, functional and anatomic requirements of a user at work can be attained by means of various technologies and areas of operation. Which design is the best and most adaptable depends on the user. Nevertheless, even the best ergonomic chair comprising the best technical solutions will not help you if your sitting posture is not correct. REMEBER: The pains in your back keep you company every minute of your work.
HOW TO SIT?
Sitting puts a lot of strain on out back and causes a certain strain on the spine and dorsal muscles. A modern office chair will help you to reduce the effects of the strain and improve your overall state of body and mind.
The purpose is not to sit IN the chair but WITH the chair.
The most important rules of healthy sitting are:
- Always sit in your chair IN THE UPRIGHT POSITION and LEAN against the back of the chair.
- While sitting change your position by moving the upper part of your body as frequently as possible. Thus you will avoid muscle cramps – dynamic sitting.
- Make sure that the angle under your knees, in the area of hips and ulna is at least 90°, if at all possible, lean the seating forward when you are bent over the table – negative pitch.
- Make use of all the advantages of your ergonomic office chair.
Changing the position and active movement at the working table has a positive impact on our well-being and increases working ability. Sitting has to become dynamic and must by no means be static. Physical exercises at your workplace are the best way to help you to maintain correct sitting posture while working.