Ergonomics follows a very simple basic
model that derives from physics: When you impact a body with a certain stress, the body will react with a
corresponding strain. Since a standard method causes a
stress that is typical for this standard method, the strain as a reaction to
this typical stress situation should be typical, too.
The intensity of the strain, however, is
not the same. It depends on the worker: his personal attributes, his abilities
and his skills (together they form the capability for work). And
it varies due to the actual disposition and motivation (together
called readiness for work), and his health.
If the strain overruns the permanent
work load, it may have two consequences: On one hand the body is pushed to
improve its capacities. We use this effect for active training and conditioning.
But on the other hand, acute or chronic damage can occur. Therefor breaks
for recovery are necessary and should actively be provided by the employer.