Do you work behind computer and you would like to sit correctly, better and especially more healthy so that your spine wouldn’t suffer so much? We would like to convey you the best advices for which your body will only thank you.
Human being was created for movement and physical burden, in order to withstand the forces of the external environment and take care of his/her family or himself/herself. That implies that man had to climb on the trees, run, swim and much more. In most cases man remained keeping straight body posture. But in nowadays world, static working position is prevailing, whether it is in office or car, instead of developing the movement abilities. We are not “built” for such lifestyle. That is accompanied by slouched back in an incorrect position for our vertebral discs. We won’t time travel, but we can remind ourselves of the basic principles and rules how to minimize the impact and damage on our spine, resulting from incorrectly set environment in which we work in a static position.
WHY IS LONG-TERM SITTING SO DANGEROUS?
Long-term activation of the muscles decreases nutritioning needed for their function and consequently also for nutritioning of the vertebral discs. The condition of the vertebral discs is determined by whether it has sufficient blood supply and nutritioned by bodily fluids. Determining factor for movement of the spine are sufficiently nutritioned and blood supplied vertebral discs and muscles. Sitting in an incorrect static position, during which the muscles are permanently stretched leads to their lower blood supply and shortening, muscle spasms and back pains. Blood vessels going through the muscles get restricted when the muscles are clenched. Permanent pressure on the vertebral discs squeezes out the inner fluid of the vertebral disc (red on the picture), which loses the ideal shape after the liquid is squeezed out as well as flexibility. The effect of excessive muscle spasms leads to activation of other muscles, which can by a sudden or abrupt movement and burden creates significant pressure on the vertebral discs, and that can lead to even bigger damage. Herniated discs are then pushing on the nerve fibres which results in pain - back immobility. And that starts a vicious cycle.
HOW TO HELP YOUR SPINE AND YOUR WHOLE BODY IN AN INCORRECTLY BURDENED POSITION AT WORK?
Let’s start with the place where it all starts, and from which most problems ignite. That place is your working desk. Its dimensions are derived from anthropometry and optimal body posture during work. The height of the working surface should be between 60-82 cm (23-32 inches), according to the height of the person. The size of the working desk should secure comfortable and correct arrangement of all objects needed for work. Nowadays it is especially monitor, keyboard and mouse.
IMPORTANT DIMENSIONS FOR SITTING IN FRONT OF PC
Monitor and keyboard should be placed in the axis of your seat. Monitor should be in the level of your eyes. It is very inconvenient when you have to turn your head in order to look into the monitor. It is important to eliminate the reflections from monitor or display on a notebook. All the needed tools and objects supporting the working performance should be correctly placed so that there would be no unwanted curving in the spine. The keyboard and mouse should be ergonomical and close to each other. If we work mainly with monitor, it should be directly facing us, and paperwork should be next to the keyboard. If we work mainly with documentation, the paperwork should be done in the middle. When we do a transcript, we should use a paper holder. The monitor should have an option of height regulation, as well as tilting option. When we work with two monitors we should keep in mind which one will we use as the main one, according to that we determine the position on our desk.
It can be simply said that the upper edge of the monitor should be in the level of our eyes, and the distance of the monitor from our eyes should be on about the 1-2 diagonal size of the monitor, or ti should be determined by the height of the monitor and the distance between your eyes which means 1 : 2, but at least 500 mm (19.68 inches). It is said that 50-70 cm is optimal and the angle of view should be between 0-60 degrees.
If you are using phone often, it is better to use a headset
Choosing a chair
Just as it is to pick an ideal table, it is just as important to decide to go for a good chair ideal for healthy sitting, and you should pay close attention to which chair you will pick. Choosing an ideal chair for sitting is usually a difficult task. The basic principle is that it should support straight back posture. The height of the backrest should range between 38 - 52 cm, according to the height of the person. The height of the seat should be around 401 - 52 cm, again that is determined according to the height of the person. Here are few basic types with different functions and mechanisms:
- Permanent contact - the backrest is in constant contact with the back of the person. The backrest can be tilted. Often times you can also set a height of the backrest and seat by this kind of chair. Its advantage is low price.
- Rocking mechanism - the angle of the seat doesn’t change by these chairs. The sitting comfort is secured by a turning point, which can be moved forwards. We can also set how smooth force of resistance we want and move the chair into several positions. We can of course also regulate the height of the seat.
- Asynchronous mechanism - it enables you to configure the tilt of the backrest and seat independently on each other. It is usually controlled by three handles, which regulate the angle of title of the backrest, tilt of the seat and height of the seat. The mechanics will enable you to sit in many positions.
- Synchronous mechanism - you can regulate the movement of the backrest and seat simultaneously, and you constantly adapt the shape of the chair to your movements. It is also possible to configure the force of pressure and height of the seat.
CORRECT BODY SETTING
Apart from correctly adjusted working environment, it is also important to realize the correct body posture. We should remember that:
- Elbows should be in a 90 degree angle, and the forearms should be in horizontal position to the desk.
- Legs should be in a right angle as well. In case it’s needed we can use a special pad.
Healthy back is a foundation of every movement and joy from movement. Therefore let’s give it a chance and don’t damage your back with incorrect sitting.
Author: FYZIOklinika physiotherapy Ltd., Prague, Czech Republic
Source: Clinical experieince in private practice and physioteherapeutic field, FYZIOklinika