Fysisk variation och belastningsbesvär i arbetet

10. Physical variation at work
and musculoskeletal disorders –
summary in English
• More variation in physical workload is considered both by researchers
and practitioners to be an effective intervention against
fatigue and musculoskeletal disorders in jobs characterized by
repetitive movements and constrained postures.
• ”Variation” in physical workload can be defined as the change in
exposure across time.
• Three basic aspects of variation can be identified: how much load
changes across time, how often it changes, and to which extent similar
sequences of load occur during work. These three aspects can
change independent of one another.
• ”Diversity” can be defined as the extent to which exposure entities
differ. Entities may, for instance, refer to work tasks or individuals.
Combining work tasks will lead to increased variation only if the
tasks differ considerably in physical work load.
• Studies in work physiology clearly show that variation in physical
workload has a significant influence on fatigue and recovery.
• The time-line of changes between periods of ”high” workload and
periods of recovery is probably more important in determining the
development of fatigue and disorders than the load level per se.
• Physical variation in a job comprising several tasks can be manipulated
in three different ways: by changing the contents or conditions
in individual tasks, by changing the time-line and proportions
of tasks relative to each other, and by adding new tasks to the
job.
• Few studies are available of physical variation in individual tasks
and how it is affected by equipment, task contents, and conditions
when performing the task. Studies of the effectiveness of such
initiatives on fatigue and disorders are also few; they mainly deal
with the effects of breaks from productive work and very rarely
document whether anything actually happened to physical variation.
• There is a need for more knowledge on the level and variation of
physical workload in different jobs and tasks. This information is
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