Ergonomic Principles
Almost a fourth of all work incapacity days is caused by problems with the musculoskeletal system.
| Disease of musculoskeletal system | 23,7% |
| Mental-health and behavioural disorders | 16,8% |
| Disease of respiratory system | 14,6% |
| Injuries and intoxication | 8,1% |
| Disease of digestive system | 6,5% |
| Disease of digestive system | 6,5% |
Source: Barmer Health Report 2008
According to estimations of the Federal Institute for Occupational Safety and Health (BAuA), diseases of the musculoskeletal system cause production losses of around 8,5 billion Euros per year.
Often the reason is physical inactivity.
The passive musculoskeletal system
Spine and intervertebral discs
In an upright posture when standing, the shape of the spine resembles a double “S”. In the region of the lumbar vertebra the spine bulges to the inside (lordosis), in the region of the vertebra of the chest it bulges to the outside (kyphosis) and within the neck it bulges back inside. The intervertebral discs located between the single vertebras are thereby equally incriminated.
If the trunk is moved, the respective ends of the vertebras are approaching and the intervertebral discs are squeezed in these regions. This also happens when sitting on a chair without back or cymbal rests. The cymbal overturns backwards and the so called hyperkyphosis is the result. Hence office chairs should always have an ergonomically designed seating surface and sufficient high back rest with lumbar support.
A suitable swivel chair should also have a synchronous mechanism, which allows for dynamic seating and relaxed settle back, as intervertebral discs also need physical movement. Their nutrient supply is raised by diffusion, which is the transport of nutrients via pressure drop or alternating squeezing and releasing of the intervertebral discs. Therefore frequent posture changes are ideal.
The active musculoskeletal system
Muscular system
As well as the intervertebral discs the muscular system needs movement. Static posture leads to tensions. Therefore it is even more important to integrate physical movement and variety in the work routine. Appropriate instruments are dynamic sitting and a stand-sit-dynamic.
Consequences of physical inactivity
- Reduction of muscle activity
- Exposure of intervertebral discs
- Impairment of blood circulation and oxygen supply of brain and organs
