Back Problems

Ergonomics
 

Back Problems / Most frequent problems / How to make the right choice ...

Sitting should not be just comfortable, but more healthy.

With the gradually changing face of work, the time during which we are sitting is getting much longer. If we spend six or more hours sitting daily on the job and an additional five hours in the car, by watching TV, at the dinner table, in the cinema or theatre, we can get an unbelievable 80 thousand hours during our working lives. And what kind of sitting is this?

The answer can be obtained from recently conducted studies:
Almost 67% of all office workers sit incorrectly. What are the consequences of this? Health problems, reduced work efficiency and lower motivation to work.
 

Most frequent problems

The biggest problems we face to our health are caused mainly by stiff posture while sitting. Health difficulties may occur such as back pain, headache, improper blood circulation, varicose veins, digestive and respiratory complaints, muscular cramps and strain. Our spine holds the entire body in an upright posture and is involved in almost all our movements – from lifting a telephone receiver through walking. Its double S-shaped curve is essential for keeping our bodies well balanced. The largest curve consists of the five lower vertebrae therefore these must bear most of the weight and withstand the greatest load. Muscles play a substantial role in the development of back pain and spinal diseases. Incorrect muscle strain may cause an unbalanced action similar to a lever action.

Coordination of our muscles may be more or less affected in two ways: our muscles are often weak, but they are exposed to an increased tension equally often. Although back problems are mostly caused by muscles, they most often manifest themselves as damaged vertebral discs and worn-out cartilage in our joints.

The cartilage contains no blood vessels. Simply said, it receives nutrition by soaking up nutrients from its environs, while the waste substances such as products of metabolism travel in the opposite direction – as if a sponge is being squeezed. Soaking up and squeezing out must alternate in regular intervals, so that the metabolism in the cartilage could run at its optimum. During static load, as sitting actually is, the squeezing out is prevalent with only a few nutrients getting into the cartilage.

While sitting, the vertebral discs are constantly compressed and exposed to excessive stress that is up to 50% higher than during standing posture. Sitting causes strain in the body. Scandinavian studies have shown that the strain is even doubled during typewriting. Typing at a computer keyboard brings about twice as much strain as is caused by typewriting!
 

What is healthy?

We can find a healthy seating solution in so called dynamic sitting, enabling a person to change postures as needed. The upright sitting posture can be maintained by an appropriately shaped seat and backrest, with a special focus on the support of lumbar and pelvic areas. It is important that a work chair enables us forward movement (work posture) as well as backward movement of our body (relaxation posture), with continual back support. Simultaneous motion of the backrest and the seat – the so called synchronous mechanism – will enable us to lean back with the lower part of the body remaining even after repeatedly straightening up in the same position on the seat, thus the body on the chair can be seated in an optimum position. Due to the synchronous mechanism, our back is continually exposed to pressure from the backrest, which prevents the dorsal muscles from weakening. The synchronous mechanism ensures that the backrest and seat support can be adjusted to the movement of our body; we are talking about so called active sitting. The chair allows for adjustment of counter-pressure ranging between 50 and 125 kg body weight to suit different weight categories. The seat front edge should be rounded not to exert pressure on the blood vessels under the knees.
 

How to make the right choice?

What does it exactly mean to sit properly “in a healthy manner”, and especially, which furniture features help us to take a correct seating position? Chairs have several controlling elements which manufacturers try to minimise, offering thus easy control in combination with all-purpose shaping of the seat and backrest. Each set of chair models features a wide range of covers and surface finishes as well as caster types, materials and shapes of armrests.