Ergonomics – What Works?
Dr Richard Graveling FIEHF
Principal Ergonomics Consultant
IOM, Edinburgh
INSTITUTE OF OCCUPATIONAL MEDICINE
www.iom-world.org
Ergonomics – What Works?
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Brief overview of Ergonomics
Comments on two Cochrane reviews
Exploration of what works in Ergonomics
Ergonomics – What Works?
Brief overview of ergonomics
• What ergonomics isn’t!
Ergonomics – What Works?
Brief overview of ergonomics
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There is a lot more to ergonomics than
office chairs (and computers).
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Ergonomics is about designing for people,
wherever they interact with other people,
products, systems or processes.
Ergonomics – What Works?
Brief overview of ergonomics
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The scientific discipline concerned with the
understanding of interactions among human
and other elements of a system, and the
profession that applies theory, principles,
data and methods to design in order to
optimise human well-being and overall
system performance. (ISO 26800)
Ergonomics – What Works?
Brief overview of ergonomics
• When a pilot misunderstands a poorly
designed control and a plane crashes into
the Atlantic – that’s ergonomics.
• When systems don’t prevent a patient from
being given ten times the safe dose - that’s
ergonomics.
• When a catalogue of design, system and
human mistakes result in the worst ever
offshore oil disaster – much of that is
ergonomics.
Ergonomics – What Works?
Two Cochran reviews:
• Hoe et al (2012) Ergonomic design and
training for preventing work-related
musculoskeletal disorders of the upper limb
and neck in adults.
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Verhagen et al (2013) Conservative
interventions for treating work-related
complaints of the arm, neck or shoulder in
adults.
Ergonomics – What Works?
Two Cochran reviews:
• Few, if any of the interventions appeared to
attempt to relate the nature of the problem
to the nature of the disorder.
• For example, one review finding was for
moderate evidence that providing a
different mouse didn’t prevent
neck/shoulder disorders. Why would you
expect it to?
Ergonomics – What Works?
Other evidence for prevention:
• There are a number of case studies in the
literature – but they don’t meet the rigours
of reviews such as Cochrane due to no
control group, no blinding, etc.
Ergonomics – What Works?
Other evidence for prevention:
• For example, Tesh (2014) identified a
problem with the design of a medical
equipment production process.
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A focussed intervention produced positive
benefits in a reduction in the incidence of
MSDs amongst the workforce and a financial
payback time within less than two years.
Ergonomics – What Works?
Other evidence for prevention:
Make the punishment fit the crime:
• In a similar vein, Anema et al (2004)
reported on a study of RTW interventions in
sufferers of chronic LBP.
• The interventions weren’t the same in each
case – but were tailored to the needs of the
individual.
• The outcome was a significant reduction in
sickness absence.
Ergonomics – What Works?
Make the punishment fit the crime:
• Not all MSDs are caused by work.
• Intervention must relate to nature of injury
and understanding of probable causal
mechanism.
• For example, where is the value in providing
new seats for sewing machine operators
suffering from neck and shoulder problems
(as was reported in one ineffective study)?
Ergonomics – What Works?
Problems stem
from prolonged
neck flexion
and/or shoulder
elevation
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Any solution must address these sources –
modifying the ‘offending’ posture.
Ergonomics – What Works?
Why fixate
on this?
When faced with this?
Ergonomics – What Works?
What does work?
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Understand aetiology
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Observe
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Apply ergonomic principles
Ergonomics – What Works?
Understand aetiology:
• Shoulder impingement reduces blood flow –
both mechanically and hydrostatically.
Ergonomics – What Works?
Observe
Ergonomics – What Works?
Provided new tool which was a
more appropriate shape.
Ergonomics – What Works?
Understand aetiology:
• Wrist flexion/extension increases pressure
in carpal tunnel (now part of PD A12)
Ergonomics – What Works?
Understand aetiology:
• Gripping (and lifting) increases pressure in
carpal tunnel (not part of PD A12)
From: Rempel et al, 1994
Ergonomics – What Works?
Understand aetiology:
• Work with computer keyboard or mouse can
increase carpal tunnel pressure.
From:
Rempel et
al, 1994
Ergonomics – What Works?
Understand aetiology:
• Epidemiology suggests relationship between
CTS symptoms and computer work NOT
causal. Supported by pressure studies
which suggest greater pressure required for
vascular effects in nerve.
Ergonomics – What Works?
Observe: Provocation not
causation – but still need
to address.
Make sure mouse fits
hand and enables a
straight wrist posture
Ergonomics – What Works?
Different keyboard or mouse can
be helpful – if it reduces gripping
(mouse) or improves wrist posture
when mousing or keying.
Ergonomics – What Works?
Different keyboard or mouse can be helpful – if
it reduces gripping (mouse) or improves wrist
posture when mousing or keying.
Ergonomics – What Works?
Observe
Ergonomics – What Works?
Observe: How do we deal with these?
Ergonomics – What Works?
Apply ergonomic principles:
• The human body is designed for movement.
• There is a growing body of evidence that
the absence of movement plays a significant
role in the causation of (office) MSDs.
• The effects of lack of movement are
exacerbated by (relatively) high muscle
forces.
• The further away a joint angle is from
neutral – the greater the potential strain.
Ergonomics – What Works?
Keep moving?
Ergonomics – What Works?
Questions or comments?
(thanks to Calman and the Royal College of Psychiatrists)