Physical risk factors include those pertaining to the person and
those pertaining to the job. Person-related risk factors include
age, sex, and conditioning. Most studies of the work force have
shown an increased incidence of back injury with age. An equal incidence
of back pain for men and women has been found. The one exception
here is the postmenopausal osteoporotic woman, whose incidence of
back pain and back injury is higher than that of men of the same
age. Recent studies, with careful strength measurement,
indicate that proportionate strength and conditioning of the back,
abdomen, arms, and legs may be protective against back injury.
Job-related physical risk factors for back injury include frequent
lifting of weights of more than 10 kilograms, frequent bending and
stooping, truck driving, and exposure to whole-body vibrations.
Each of these risk factors has been shown, in certain studies, to
increase the risk of low back pain. However, other studies have
found that these factors did not appear to increase the incidence
of low back pain. The search for physical risk factors for low back
injury in the work place has indeed been confusing.
Many newer studies indicate that psychosocial factors may have
more predictive value than physical factors in determining who is
at risk for back injuries in the work place. These psychosocial
risk factors for low back pain include job dissatisfaction, incompatibility
with colleagues and supervisors, and poor sense of self worth.
Interventional training programs can decrease the number of reported
back injuries in the work place as well as the number of days lost
to such injuries. This effect has been seen in controlled studies
that have found that employees in training programs had fewer injuries
and missed far fewer work days than their colleagues who had no
such training. These training episodes consisted of 20 minutes of
instruction in exercise and in proper body mechanics. The most effective
programs occurred during normal working hours once or twice a week.
In the end, the study group ended up with improved lumbar muscle
strength, significantly fewer episodes of back pain, and fewer work
Studies that include the use of lumbosacral corsets have suggested
that these devices are beneficial in addition to training but that
they have less effect if they are the only intervention used. Detrimental
effects of the use of these corsets have not been found. There is
no evidence to suggest loss of strength as the result of the intermittent
use of a lumbosacral corset.
Intervention in the form of training programs and corsets has been
shown to be cost efficient. When compared to control groups, the
exercise groups have shown a significantly lower number of days
lost to back injury. The savings from a decreased number of days
lost has far offset the expense of instituting the program.
The perceived benefits of these training programs are many. Training
programs have been shown to increase lumbar and abdominal strength.
They also improve lifting technique and heighten the awareness of
the need for using proper lifting technique. All of these are positive
physical changes that would appear to naturally decrease the risk
There are other less easily measured effects that may be more significant.
These training programs let employees know that someone "finally"
cares about them. These programs help foster a camaraderie among
employees and possibly even between employee and supervisor. They
may help the workers take more pride in themselves because of their
improved physical fitness. All of these factors can combine to improve
the employees' sense of self worth.
Some straightforward recommendations for avoiding the physical
risk factors for low back pain are listed in the table below. Eradicating
the psychosocial risk factors poses a more formidable challenge
for both employers and health care professionals.
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