What are work-related
musculoskeletal disorders (WRMSDs)?
Work-related
musculoskeletal disorders (WRMSDs) are a group of painful disorders of muscles,
tendons, and nerves. Carpal tunnel syndrome, tendonitis, thoracic outlet
syndrome, and tension neck syndrome are examples.
For
the purpose of developing injury prevention strategies, many health and safety
agencies include only disorders that develop gradually and are caused by the
overuse of the above constituents of the musculoskeletal system. The traumatic
injuries of the muscles, tendons and nerves due to accidents are not considered
to be WRMSDs or are considered separately. However, there are organizations,
such as the European Agency for Safety and Health at Work, that include acute
traumas and fractures within in the WRMSD group.
This
document will discuss those injuries resulting from overuse and those that
develop over time. Work activities which are frequent and repetitive, or
activities with awkward postures cause these disorders which may be painful
during work or at rest.
Almost
all work requires the use of the arms and hands. Therefore, most WRMSD affect
the hands, wrists, elbows, neck, and shoulders. Work using the legs can lead to
WRMSD of the legs, hips, ankles, and feet. Some back problems also result from
repetitive activities.
Are there
other names for WRMSDs?
WMSDs are very difficult to define within traditional disease
classifications. These disorders have received many names, such as:
- Repetitive motion injuries.
- Repetitive strain injuries.
- Cumulative trauma disorders.
- Occupational cervicobrachial disorders.
- Overuse syndrome.
- Regional musculoskeletal disorders.
- Soft tissue disorders.
Most of the names do not accurately describe the disorders. For example,
the term "repetitive strain injuries" suggests that repetition causes
these disorders, but awkward postures also contribute. These terms are used
synonymously. In the absence of an agreement, WRMSD term is used in this
document.
What are the risk factors for WRMSDs?
WRMSDs arise from arm and hand movements such as bending, straightening,
gripping, and holding, twisting, clenching and reaching. These common movements
are not particularly harmful in the ordinary activities of daily life. What
makes them hazardous in work situations is the continual repetition, often in a
forceful manner, and most of all, the speed of the movements and the lack of
time for recovery between them. WRMSDs are associated with work patterns that
include:
- Fixed or constrained body positions.
- Continual repetition of movements.
- Force concentrated on small parts of the body,
such as the hand or wrist.
- A pace of work that does not allow sufficient
recovery between movements.
Generally, none of these factors acts separately to cause WRMSD. WRMSDs
commonly occur as a result of a combination and interaction among them.
Heat, cold and vibration also contribute to the development of WRMSD.
How do WRMSDs occur?
WRMSDs that develop gradually as a result of repeated trauma.
WRMSDs include three types of injuries:
- Muscle injury.
- Tendon injury.
- Nerve injury.
What are the symptoms of WRMSDs?
Pain is the most common symptom associated with WRMSDs. In some cases
there may be joint stiffness, muscle tightness, redness and swelling of the
affected area. Some workers may also experience sensations of "pins and
needles," numbness, skin colour changes, and decreased sweating of the
hands.
WRMSDs may progress in stages from mild to severe.
Early stage: Aching and tiredness of the affected limb occur during the work
shift but disappear at night and during days off work. No reduction of work
performance.
Intermediate stage: Aching and tiredness occur early in the work
shift and persist at night. Reduced capacity for repetitive work.
Late stage: Aching, fatigue, and weakness persist at rest. Inability to sleep
and to perform light duties.
Not everyone goes through these stages in the same way. In fact, it may
be difficult to say exactly when one stage ends and the next begins. The first
pain is a signal that the muscles and tendons should rest and recover.
Otherwise, an injury can become longstanding, and sometimes, irreversible. The
earlier people recognize symptoms, the quicker they should respond to them.
How are WRMSDs recognized?
The evaluation of WRMSDs includes identifying workplace risks.
Evaluation begins with a discussion of the person's employment and requires a
detailed description of all the processes involved in a typical workday.
Consideration is given to the frequency, intensity, duration, and regularity of
each task performed at work.
Diagnosis of WRMSDs is confirmed by performing laboratory and electronic
tests that determine nerve or muscle damage. One such test,
electroneuromyography (ENMG), encompasses two areas: electromyography (EMG) and
nerve conduction velocity (NCV). Magnetic resonance imaging (MRI), an
alternative to x-rays, provides images of tendons, ligaments, and muscles and
improves the quality of the diagnostic information.
How are WRMSDs treated?
The treatment of WRMSDs involves several approaches including the
following:
- Restriction of movement.
- Application of heat or cold.
- Exercise.
- Medication and surgery.
How can we prevent WRMSDs?
Hazards are best eliminated at the source; this
is a fundamental principle of occupational health and safety. In the case of WRMSDs,
the prime source of hazard is the repetitiveness of work. Other components of
work such as the applied force, fixed body positions, and the pace of work are
also contributing factors. Therefore the main effort to protect workers from WRMSDs
should focus on avoiding repetitive patterns of work through job design which
may include mechanization, job rotation, job enlargement and enrichment or
teamwork. Where elimination of the repetitive patterns of work is not possible
or practical, prevention strategies involving workplace layout, tool and
equipment design, and work practices should be considered.
Job Design
Mechanization
One
way to eliminate repetitive tasks is to mechanize the job. Where mechanization
is not feasible or appropriate, other alternatives are available.
Job Rotation
Job
rotation is one possible approach. It requires workers to move between
different tasks, at fixed or irregular periods of time. But it must be a
rotation where workers do something completely different. Different tasks must
engage different muscle groups in order to allow recovery for those already
strained.
However,
job rotation alone will not be effective in reducing WMSDs if not combined with
the proper design of workstations. And it will not be effective while the high
pace of work persists.
Job Enlargement and Enrichment
Another
approach is job enlargement. This increases the variety of tasks built into the
job. It breaks the monotony of the job and avoids overloading one part of the
body. Job enrichment involves more autonomy and control for the worker.
Team Work
Team
work can provide greater variety and more evenly distributed muscular work. The
whole team is involved in the planning and allocation of the work. Each team
member carries out a set of operations to complete the whole product, allowing
the worker to alternate between tasks, hence, reducing the risk of WRMSDs.
Workplace
Design
The
guiding principle in workplace design is to fit the workplace to the worker.
Evaluation of the workplace can identify the source or sources of WRMSD. Proper
design of the workstation decreases the effort required of the worker to
maintain a working position. Ideally, the workstation should be fully
adjustable, providing a worker with the options to work in standing, sitting or
sitting-standing positions, as well as fitting the worker's body size and
shape.
Tools
and Equipment Design
Proper
design of tools and equipment significantly decreases the force needed to
complete the task.
Providing
the worker with the proper jigs or fixtures for tasks that require holding
elements saves a lot of muscular effort in awkward positions.
Good
tools, maintained carefully and where necessary frequently changed, can also
save a lot of muscle strain
Work
Practices
A
well-designed job, supported by a well-designed workplace and proper tools,
allows the worker to avoid unnecessary motion of the neck, shoulders and upper
limbs. However, the actual performance of the tasks depends on individuals.
Training
should be provided for workers who are involved in jobs that include repetitive
tasks. Workers need to know how to adjust workstations to fit the tasks and
their individual needs. Training should also emphasize the importance of rest
periods and teach how to take advantage of short periods of time between tasks
to relax the muscles, and how to consciously control muscle tension throughout
the whole work shift.
Increased
communication and support together with an increased ability of the worker to
control his job (where possible) are work practices that improve worker’s
satisfaction and have a positive impact on reducing the risk of WRMSDs.
Posted by Indian Safety Association
www.doshti.com
No comments:
Post a Comment