IS IT GOOD TO WEAR A BACK BELT TO
PROTECT YOUR BACK?
is often claimed that wearing a back belt will support your spine and prevent a
back injury. Workers at certain
companies are required to wear them. But
do these supports do what is claimed? Or
could they actually cause harm?
Lower back pain is an
enormously expensive problem and accounts for a quarter of all payments for
workers' compensation claims. Back
pain is the second most common reason for visiting a doctor, after flu and
colds. In order to deal with the
problem, many employers, and employees, have chosen back belts to provide
support to the lumbar region of the spine.
look at the scientific evidence about whether back belts might help to support
the back, whether there are any risks associated with wearing them, and whether
such belts should be recommended or not.
How might back belts help to support the back? They do not hold the back in, as many presume. Back belts function primarily to hold the stomach in, thus increasing intra-abdominal pressure. This has led some to refer to these belts as abdominal belts rather than as back belts. But how does increasing intra-abdominal pressure support the spine? We will briefly review the intra-abdominal balloon theory and a more modern theory.
Intra-Abdominal Balloon Mechanism
It was originally proposed
by Bartelink in 1957 that increased intra-abdominal pressure would decrease the
compressive load on the spine through the intra-abdominal balloon mechanism.(3)
To begin with, you must think of the abdominal cavity and the abdominal
organs as a squishy liquid. Then
realize that the abdominal cavity becomes a closed chamber when we bear down and
hold our breath, which we instinctively do when we lift heavy things.
This chamber is closed on the bottom by the anal sphincter and on the top
by the diaphragm. When bearing
down, the abdominal contents tend to push outwards. But if we contract our deep abdominal muscles—the obliques
and the transverse abdominus muscles—or we wear a thick belt, the abdominal
contents are forced upwards rather than outwards.(4 p.109)
This theoretically provides a decompressive effect on the lumbar spine.
Since the crura of the diaphragm is attached to the first 3 lumbar
vertebrae, when the diaphragm is pushed upwards, it exerts a traction force on
the lower lumbar spine (L4 and L5). It
was also theorized that since this balloon mechanism makes the spine more rigid,
it would decrease the amount of work required of the erector muscles to prevent
us from falling forwards. Kapanji
estimated that this abdominal support mechanism acts to reduce compression
forces on the L5/S1 disc by 30% and reduces the force required by the erector
spinae muscles by 55%. (4, p.198).
But more recent scientific evidence fails to support some of these theoretical assumptions. Such recent studies reveal that an increase in intra-abdominal pressure actually results in an increase (rather than a decrease) in compressive force on the lower spine.(5,6) And there is no decrease in the amount of work required of the lower back muscles.(7) However, by stiffening the trunk, increased intra-abdominal pressure may prevent the tissues in the spine from strain or failure from buckling. Such intra-abdominal pressure may also act to reduce anterior-posterior shear loads.(8) In other words, support for the spine is provided, without reducing compression to any appreciable degree.
Belts may also help to protect the spine by limiting the range of motion that occurs when bending or twisting, though this effect is less than expected.(9,10) However, since when the spine bends more, it is more vulnerable to injury, if these belts reduce extreme bending at all, they may be beneficial.
The main risk associated
with wearing a back belt is that during the period of wearing it, the supportive
spinal muscles—the deep abdominal and back muscles—that normally support
your spine will become weaker. These
muscles are less active while your spine is being artificially supported by the
belt. Muscles need to be
consistently exercised in order to stay strong.
If these muscles become weaker, when you stop wearing the belt, you may
be more likely to hurt your back. And
at least one study seems to suggest this. In
this study, there was an increase in the number and severity of back injuries
following a period of belt wearing.(11)
Another risk associated with
wearing a back belt is that it causes an increase in both blood pressure and
heart rate.(12) This may pose a
problem for those individuals with existing cardiovascular disease or risk
factors, such as hypertension.
A third risk associated with
wearing a back belt is that workers may be inclined to lift heavier objects
while wearing them. These belts may
be giving workers a false sense of security.
This could result in an increased risk of injury.
Should you wear a belt to support your back and prevent injury?
My recommendation is that
you should wear a supportive belt only for the first few days or weeks after a
severe back injury while the area is healing or only during the lifting of very
heavy objects. If you have never had a back injury, I would avoid a belt
entirely. It is more important to
focus on using proper form and posture when bending and lifting and even
sitting, and to perform conditioning exercises regularly to keep your trunk
Before requiring all your
workers to wear back belts, it would be better to have a comprehensive ergonomic
assessment of the work stations to see what can be done to reduce overloading
the spine while at work. Workers
should be educated about how the tissues of the spine become injured, proper
lifting mechanics to minimize such strain, and what to do when feeling back
discomfort prior to a severe injury occurring.
All workers should be encouraged to engage in a regular fitness program,
to lose weight if heavy, and to avoid smoking.