Most back problems are not caused by a
single injury, but rather a combination of
factors over a period of months or years. Proper
body mechanics should play an important role in
our everyday life activities in order to prevent
back pain or back injuries. This monograph offers
basic explanation and animated demonstrations of
proper body mechanics during everyday life
activities, i.e. bathing, dressing, transfers,
home management and child care.
of back strain/injury:
- Bad posture
- Incorrect movement
during daily activities
- Poor pacing of
- Poor general
Basic Spinal Anatomy
|The Spine is made up of 24 bones (the vertebrae).|
The vertebrae are aligned in three natural curves
forming an "S" shape. Each curve is
labeled by the region it is located.
Neck – cervical curve (lordosis)
Mid Back – thoracic curve (kyphosis)
Back – lumbar curve (lordosis)
the spine to support the back in this balanced
position. But the abdominal muscles are extremely
important as well.
Intervertebral Discs are located between each vertebrae,
discs act as shock absorbers or cushions and
allow joints to move smoothly. Discs are
generally labeled by the vertebrae they are
between, i.e. the "L1-L2 disc" is
located between the first and second lumbar
Spinal nerves connect
the central nervous system (the spinal cord) to
the peripheral nervous system (nerves going to
muscle, internal organs, skin). They exit from
round openings ("foramena") between
strong bands of tissue which are much less
stretchable than muscle or skin. Ligaments
surround the bony vertebrae to provide support.
The ligament in the front of the spine is wide
and strong. The ligaments located in the back of
the spine are relatively thin and narrow.
Key Elements of Body Mechanics
The following pictures
illustrate the key principles of body mechanics. They
form the foundation for the proper way all activities
should be performed to prevent back injury.
Center of gravity
is the point of balance between the upper and
lower body. For women, this point is
approximately at the belly button and for men, 1
inch above the belly button. The difference is to
accommodate for anatomical structure with men
generally having wider shoulders and women wider hips. Although one can not actually
"see" center of gravity, we can
illustrate where it is and how it works.
To prevent back injuries while doing
activities, center of gravity should remain close to
one’s body (see figures 2 -4 above). It is very important
to bend knees and lower oneself with a straight back when
lifting. Lifting this way takes strain off of back
muscles and enables the stronger leg muscles and arms to
do the work. If one should attempt to lift something by
bending forward over it, the center of gravity shifts
forward and back muscles have to work very hard to
prevent one from falling forward (figure 1). This can
place tremendous strain on the back.
Base of support is that which supports
an individual’s center of gravity. When standing, base of
support equals the feet shoulder distance apart. This
stance is important when doing lifting activities because
it gives one a better "base" for balancing and
avoids using the smaller muscles of the back to keep one
upright and prevent falling.
Additional Back-saving Tips:
Functional Application During Common Daily Tasks
illustrations show examples of sitting, bending, and
reaching which contribute to back strain and some
|Poor Mechanics||Notes||Good Mechanics|
making a bed…
lift" can be used to load/unload a washer.
Squatting is better than bending from the waist
when unloading a front-loading washer or dryer.
| Place one foot on lip|
of open cabinet under sink to effectively broaden
your "base of support". Place the
opposite hand on counter top for support to keep
standing at a counter for extended periods of
time, place a foot on the bottom shelf of the
open cabinet below . This reinforces a good
posture while washing dishes.
lift" can be used to load the dishwasher.
Kneeling on one knee can also be used to load and
Index to Back Saving Animations
The following section
contains links to animations which demonstrate proper
forms of movement/lifting in various situations.
Animation image file sizes range from 175K to 398K but
typically start "moving" during the download.
To view the animations, you do not require any special
"plug-ins" but you will need to be using a
browser that can display animated GIFs (Netscape 2.0 and
above; Internet Explorer 3.0).
To view an
animation, just ‘click’ on a thumbnail image below.
Printed Resources for Patient Education:
Back Owner’s Manual. Krames
San Bruno, CA. 1991
Back to Backs: A Guide To
Preventing Back Injury. Krames
San Bruno, CA. 1988.
Meinik M, Saunders R, Saunders HD.
Back Pain. Saunders Group, Chaska,
Saunders, HD. Evaluation,
Treatment and Prevention of Musculoskeletal Disorders.
Viking Press. Minneapolis, MN. 1985, pp. 260, 317.