Chapter 5 The Muscular System 185
What Research Tells Us
...about
Low Back Pain (LBP)
Low back pain (LBP) is a major
health problem. Approximately
80%–85% of people experience it
at some time during their lives.
In addition, back injuries
are the most common and
most expensive of all worker’s
compensation claims. Second only
to the common cold in causing
absences from work, the incidence
of LBP has steadily increased
in the US for the past 15 years.
This is likely due, in part, to the
increasing proportion of overweight
and obese individuals. LBP is
signifi cantly associated with excess
weight in both men and women of
all ages.
Nearly 30% of children in
the US also experience LBP.
The likelihood that children will
experience LBP increases with
age. By age 16, the percentage
of children with LBP is similar to
that of adults. Children who are
more physically active tend to incur
LBP more often than sedentary
children.
Athletes of all ages have a
much higher incidence of LBP
than nonathletes. In fact, more
than 9% of college athletes receive
treatment for LBP. Gymnasts
(particularly those who are female)
have much higher incidences of
LBP. Studies show that as many
as 85% of competitive gymnasts
experience this health problem
(Figure 5.25).
What causes LBP? Although
injuries and certain disorders
may cause LBP, 60% of LBP is of
unknown origin. Low back muscle
strains, resulting in soreness and
stiffness, can be one source of
LBP. In almost all cases of LBP,
the low back muscles are sore and
painful.
In some cases this pain
is caused by muscle injury. In
many cases, however, this pain
may be due to what is called a
sympathetic contraction of the low
back muscles. This means that
the muscles involuntarily contract
as the body attempts to stabilize
an underlying injury of the spinal
column.
Fortunately, most LBP is
self-limiting—75% of patients are
back to normal within three weeks.
Approximately 90% have recovered
within two months, with or without
medical treatment.
What can you do to avoid
developing LBP? Known risk
factors for LBP include the
following:
• sitting for prolonged periods;
• standing for long periods in an
unchanging position;
• working in an unnatural posture;
• working with one hand;
• encountering sudden or
unexpected motions; and
• performing heavy manual labor.
Taller and heavier individuals
are at increased risk for developing
LBP. Cigarette smoking is also
associated with increased risk
of LBP, most likely because
habitual smoking can contribute to
degeneration of the intervertebral
discs.
Taking It Further
1. Why do you think LBP is so
common? Based on what
you have read about LBP, do
you think a higher or lower
percentage of people will have
LBP in the future? Explain
your reasoning.
2. What do you think self-limiting
means? Do some research,
write a defi nition, and then
give some examples of self-
limiting behavior.
3. Conduct a survey among
people you know to fi nd out
who has and who has not
experienced LBP. Include
males and females, athletes
and nonathletes, and people
of various ages in your survey.
What conclusions can you
draw from your survey about
the occurrence of LBP?
Sergej Khakimullin/Shutterstock.com
Figure 5.25 Repeated, extreme
lumbar hyperextension increases
the likelihood that female gymnasts
will develop low back pain.
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