Low
back pain is a common occupational health problem. The National
Safety Council's 1991 Accident Facts reports that back injuries
are the most frequent of all disabling work injuries in the
United States. Statistics reveal that about 31% of all workers'
compensation cases are related to back injuries. Farmers are
especially vulnerable to developing back problems, because
their work frequently incorporates activities that are thought
to be risk factors for developing low back pain.
- Lifting
objects heavier than 25 pounds or repeatedly lifting lighter
objects;
- Awkward
body posture while working;
- Prolonged
driving of such vehicles as tractors, trucks, and other
farm equipment that cause whole body vibration;
- Slips
and falls and other traumatic injuries associated with adverse
working conditions;
Men
and women are both prone to work-related back pain and the
first episode usually occurs between the ages of 20 and 40
(4). Activities that put excessive stress on the spine seem
to play a role in developing low back pain (2).
Manual
lifting of heavy objects is the most commonly cited risk factor
causing low back pain. Agricultural workers commonly lift
heavy objects such as bales of hay, sacks of feed, or even
animals, during the course of a work day. They may also be
subject to stresses associated with repetitive lifting, such
as moving bulky equipment during milking or loading and unloading
trucks and wagons. Additionally, whole body vibration delivered
by way of the buttocks and spine from vibrating vehicles such
as tractors, is thought to play a role in the development
of low back pain.
Most
low back pain associated with overexertion is short-lived.
Half of those who seek medical attention improve in the first
week and over 90% of them improve within two months, regardless
of treatment(1). Nevertheless, because people may experience
multiple episodes of back pain that may be incapacitating,
(a person suffering a low back incident appears to have about
a 2 to 4% chance of it becoming a permanent disability), low
back pain remains a significant cause of missed work days
and worker discomfort (2).
The
severity of symptoms associated with a low back disorder can
vary, ranging from relatively mild and short in duration to
pronounced and incapacitating. A low back problem can result
in stiffness and pain, along with inability to move. These
symptoms may not appear until 12 to 36 hours after the incident
occurs. Sciaticatype back pain is associated with a pain down
one or both legs and frequently numbness or tingling in the
foot and toes. Normal walking may become difficult.
Fortunately,
most sufferers from lower back pain respond to the conservative
medical management prescribed by their doctors. Therapy frequently
includes bed rest, controlled physical activity, physical
therapy, and medication. For those receiving conservative
medical therapy, follow-up evaluation is very important (1).
Once
high risk activities are recognized, then prevention and control
come into play. A combination of the following strategies
will help reduce the occurrence and severity of back disorders
in agriculture.
Although
no single lifting technique is best for all situations, the
following guidelines will be helpful in most instances:
- The
load should be as compact and light as possible.
- Lift
only loads that can be handled safely. Test the weight of
the load before trying to lift it; if it is unmanageable,
get help.
- When
lifting and lowering, get a good grip on the object and
keep it close to the body. Place your feet close to the
load and lift slowly, smoothly, and mostly by straightening
the legs. Even relatively light loads lifted away from the
body can create injurious stress levels on the spine.
- Lifting
and lowering should be restricted to the range between the
level of the hands, when standing with the arms hanging
in a relaxed position, and shoulder height.
- Do
not lift or lower with the arms extended.
- Minimize
reaching forward for an object. Move objects out of the
way first to get to the needed items.
- While
lifting, always rotate the body by moving the feet, rather
than twisting or bending the trunk.
- Avoid
repetitive lifting--alternate the task with other tasks.
- Use
mechanical assistance--lift tables, hoists, and conveyors--whenever
possible.
- Reduce
whole body vibration by driving vehicles with suspension
seats that have appropriate vibration-damping characteristics.
- Use
motor vehicles with good seat positioning and lumbar support.
- Maintain
flexibility in the workplace to accommodate people of different
sizes and shapes.
Education and training
- Consult
your doctor about safe lifting techniques.
- Strength
and fitness conditioning--Evidence suggests back strength
and overall fitness may be associated with a lower risk
for developing acute back pain.
- Back
schools teach spinal mechanics, exercise, and fitness to
individuals with back pain-- contact your doctor or local
hospital for information.
Job placement
- Job
placement is an attempt to identify appropriate jobs for
people with various physical capabilities. People exhibit
a large variation in lifting capability.
- The
goal is to obtain a good match between workers and tasks
so people can be productive in their jobs. This approach
appears promising, but its effectiveness is as yet unproven
(3).
Professional medical
care
- Medical
evaluation is especially important for anyone who is at
increased risk for developing low back pain or who already
experiences back pain.
- Medical
treatment and rehabilitation, along with job modification,
may enable people with mild back pain to continue working.
References
- Borenstein
D: "Low Back Pain," in Barker LR, Burton JR (eds): Principles
of Ambulatory Medicine. Baltimore, Williams and Wilkins,
1991.
- Chaffin
DB: "Biomechanics of Manual Materials Handling and Low Back
Pain," in Zenz C (ed): Occupational Medicine Principles
and Practical Applications. Chicago, Year Book Medical Publ.,
1988.
- Snook
SH, Fine LJ, Silverstein BA: "Musculo-skeletal Disorders,"
in Levy BS, Wegman DH (eds): Occupational Health Recognizing
and Preventing Work-Related Disease. Boston, Little Brown,
1988.
- Young
BB, Rock A, Kraus J: "Musculoskeletal Injuries: Impact on
Quality of Life and Productivity," in Holland WH, Detels
R, Knox G (eds): Oxford Textbook of Public Health. Oxford,
Oxford Publ., 1991.
Additional References
- American
Public Health Association: "Low Back Pain Syndrome," in
Weeks JL, Levy BS, Wagner GR (eds): Preventing Occupational
Disease and Injury. Washington D.C.: 1991
- Keyserling
WM: "Occupational Ergonomics: Designing the Job to Match
the Worker," in Levy BS, Wegman DH (eds): Occupational Health
Recognizing and Preventing Work-Related Disease. Boston,
Little Brown, 1988.
- Kroemer
KH: "Ergonomics," in Plog (ed): Fundamental of Industrial
Hygiene. Chicago, National Safety Council, 1988.
Publication #: 500-0992
Developed
by Wei Zhao, Project Director of Agricultural Safety and Health
Program, in consultation with Ann L. Kersting.
The
publication was made possible in part by a grant from the
National Institute for Occupational Safety and Health Program
on Agricultural Health Promotion Systems for New Jersey.
Produced by the Cook College/NJAES Office of Communications
and Public Relations
Disclaimer and Reproduction Information: Information in
NASD does not represent NIOSH policy. Information included in
NASD appears by permission of the author and/or copyright holder.
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