Technical progress has transformed physical-dynamic work into static work. This has led to muscle-skeletal problems resulting from long periods with the same posture and lack of movement, very often in a seated position.
It has been demonstrated that different jobs require different seating positions. So we need to choose a chair that is as versatile as possible, to allow the body to take up different postures throughout the working day.
The most frequent postures used in a job station with a video display terminal (VDT) screen.
The lower back support must enable an angle of around 110º to 130º between the thigh and the trunk to reduce intradiscal pressure to a minimum.
In these postures, the lower back area and the top of the back are subject to high intradiscal pressure which causes a damaging overstrain for the vertebras. This in turn may lead to nerve compression and require great muscular strain.
Sitting badly is:
A series of problems arises as a consequence of one or more of the foregoing:
ERGONOMICS OF THE NECK REST
Problems
Over time, the lack of a neck rest leads to cervical discomfort.
Solutions
Whenever your work allows you to do so, adopt relaxing positions using the synchronised mechanism to stretch and relax the neck.
ERGONOMICS OF THE LOWER BACK SUPPORT
Problems
Over time, an incorrect lower back support leads to discomfort and muscular-skeletal pathologies in this area.
Solutions
Use a chair with a curved back in the lower back region and adjust the height of the back of the chair to suit your size.
ERGONOMICS OF THE ARMRESTS
Problems
The absence of armrests leads to muscular strain on the back, shoulders and neck.
An armrest that is too high can interfere with the work plane and prevent us from getting close enough.
Solutions
Use a chair with armrests that allow the height and angle to be adjusted to support the forearms when you are working with a keyboard.
By lowering the armrests you will be able to get closer to the work plane.
ERGONOMICS OF THE SEAT
Problems
A seat that is too deep prevents you from supporting your back properly and causes pressure on the popliteal fossa (back of the knee).
A seat that is too flat or excessively soft leads to poor distribution of pressure on the buttocks and thighs.
Solutions
Adjust the depth of your seat. Choose a chair with a rounded front edge.
Choose a seat with an anatomical shape and one that is cushioned, but not excessively soft. This will enable an even distribution of weight over the entire surface.
CHAIR HEIGHT
Problems
A chair that is too high causes excessive pressure on the lower part of the thigh, making correct blood flow difficult.
Solutions
Adjust the height of your seat until the sole of the foot is completely supported.
Adjust the angle of your seat until the sole of the foot is completely supported.
N.B.: This posture, with the pelvis inclined slightly forwards, is beneficial over a short period of time, as it allows the spine to turn harmoniously and maintain an optimum.
