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“Chest Expander” for Upper Back Muscles |
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Written by Stephen E. Alway, PhD, FACSM
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Monday, 23 April 2007 |
As a 10-year-old, I used to pore over the ads in comics and then later
in muscle magazines that portrayed large muscled athletes exposing the
"secrets" of their pumped bodies. One of those ads suggested that a
superior upper body could be obtained by purchasing a "chest expander."
That forced me to save my meager allowance for months to purchase my
first elastic "chest expander." I soon found out that the chest
expander really could not effectively activate the muscles of my chest,
and any improvement in chest size would have to come indirectly through
building the back musculature. Perhaps it's not false advertising, but
it would have been helpful if the person who coined the term "chest
expander" had instead named the "upper back expander."
OK, so,
maybe it's not a great pectoral developer, but it turns out the chest
expander- whether spring cables that allow you to add and subtract
cables to adjust resistance as you need it, or elastic expanders- has
a place in "exercisedom" and is a half decent rehab tool. It's
especially useful on the days when you cannot get to the gym- maybe
you're stuck somewhere studying, or on vacation or business away from
home with no gym around. A type of chest expander popularized by
Thera-Band tubing and other elastic expanders is useful for providing
moderate resistance in rehabilitation strengthening programs. However,
the tension created by the chest expander in the horizontal elbow
extension exercise works very well for the upper back and shoulder
muscles, even in non-injured folks!
Structure and Function
Most
of the muscles in the upper back are affected by horizontal elbow
extension with the chest expander, including the trapezius, deltoid,
serratus anterior, latissimus dorsi, teres major and minor, and even
the triceps brachii.
The trapezius muscle is a large flat
triangular muscle that covers the posterior aspect of the neck and the
upper half of the back. This trapezoid-shaped muscle is attached to
part of the scapula (shoulder blade), to the base of the posterior part
of the skull, and the vertebrae of the upper and middle sections of the
spine. The superior or upper fibers lift the scapula and shoulder
structures toward the ears (shrugging), while the inferior fibers
forcefully depress the scapula. Fibers of the middle (medial) segment
of the trapezius cause an upward rotation of the scapula and this helps
to elevate the arm. The medial fibers of the trapezius help squeeze the
scapula together, and this is the region that is most active in the
chest expander exercise.
The anterior and medial parts of the
deltoid attach along the clavicle and the acromion of the scapula; the
posterior fibers of the deltoid attach to the spine of the scapula. The
anterior and middle fibers stabilize the shoulder during the chest
expander exercise. On the other hand, the posterior fibers contract
quite strongly as the expander is stretched. The fibers of all three
regions of the deltoid insert on the humerus bone at the deltoid
tuberosity (a bumpy area on the upper part of the humerus).
The
serratus anterior muscle contracts to stabilize the scapula. It's a
large muscle that attaches to the lateral part of the rib cage. Its
fibers look like ropes that can be seen just above the attachments of
the latissimus muscle fibers on the lateral side of the ribs (at least
on someone with low body fat). The fibers of the serratus run
posteriorly to attach along the medial border of the scapula. This
muscle pulls the scapula forward (protraction) and holds it against the
thoracic wall to anchor the scapula so other muscles can use this
free-floating bone as if it were a fixed bone.
The latissimus
dorsi muscle covers the greatest portion of the upper-middle and middle
parts of the back. Its fibers have attachments from the sixth thoracic
vertebra (about the middle of the back) to the iliac crest (top of the
hip bone), the ribs and a tough connective tissue sheet in the region
of the lower back called the thoracolumbar fascia. Sometimes it's
attached to the lower (inferior) part the scapula, as well. The fibers
from this vast muscle come together in a tendon, much like a fan, that
attaches to the upper (superior) portion of the humerus bone of the
upper arm. Contraction of the fibers in the latissimus muscle extends
the humerus (pulls the arm backwards); adducts the humerus (brings the
arm towards the center of the body); and medially rotates the humerus
(rotates the shoulder so that if the palm of the hand is facing
forward, it would be turned toward the body). But the expander
primarily activates the shoulder (arm) extension functions of this
muscle.
The teres major muscle begins on the lowest part
(inferior angle) of the scapula, whereas the teres minor is attached
higher (more superior) along the medial border of the scapula. Both the
teres major and minor attach to the humerus bone of the upper arm to
assist arm extension (i.e., pulling the arm and elbow posteriorly).
The
triceps brachii primarily extends the forearm at the elbow joint
(straightens the elbow), but part of it is also strongly activated to
assist in shoulder extension. The lateral head and medial heads of the
triceps brachii attach along the posterior part of the humerus starting
about two-thirds of the way toward the shoulder joint and stops short
of the shoulder joint. They do not cross the shoulder joint and
therefore function only to extend the forearm at the elbow joint. The
long head of the triceps brachii (sometimes called the "inner head")
begins on the scapula just below the head of the humerus at the
shoulder joint. The long head joins the other heads to form part of the
triceps tendon that crosses the elbow joint to extend the forearm
(straighten the elbow). However, the long head also extends the arm at
the shoulder joint.
Horizontal Elbow Extensions (Chest Expander)
There
are many types of movements that can be readily accomplished with
expanders, including versions of curls, side and front lateral raises
and French presses. The focus here will be on the upper (superior) back
and shoulder musculature that's affected by the horizontal elbow
extension chest expander.
1. Take a tight grip on than
handles at either end of the expanders. The expanders should begin in
front of your torso. Raise your arms and forearms until they are
parallel to the floor and maintain this arm height throughout the
exercise.
2. Begin with your elbows pointing outward and with
your palms facing each other and your hands at the level of your
sternum. Apply constant tension as you extend (straighten) the elbows
and at the same time pull your shoulders posteriorly and squeeze your
scapula bones together.
3. Continue straightening your
elbows and pulling your arms posteriorly, but do not let your shoulders
drop. Keep pulling until your elbows are straight. Hold this position
for a count of two.
4. Slowly return your hands to the
starting position. Stop just short of losing all of the tension in the
expander, then reverse the direction of your hands to complete the next
repetition.
This exercise will activate the middle parts of the
trapezius, posterior deltoid, teres and latissimus dorsi muscles quite
strongly as arms and elbows are moving posteriorly (i.e., shoulder
extension) and the scapulae are squeezed together. The long head of the
triceps brachii will be activated to assist in shoulder extension, but
it and the other two heads will be contracted strongly as the elbow
joint is straightened. This results in double duty for the long head of
the triceps, and you'll feel an intense burn in this muscle after only
a few sets. The medial head of the deltoid is active to maintain the
shoulder in an abducted position throughout the exercise, but this is
an isometric contraction.
In contrast, you should find that
your posterior deltoid fibers might quickly feel as if they have been
set ablaze by a small blast furnace. The serratus anterior acts almost
invisibly to stabilize the scapula and keeps it close to the ribs as
the scapulae are squeezed together under tension. The anterior and
middle regions of the deltoid help stabilize the shoulder to increase
the effectiveness of the arm extension movements. The shear number of
muscles that are activated by the chest expander exercise makes this a
very good exercise when conventional training equipment is not
available or when rehabbing injured muscles.
Make no mistake;
you cannot build thick and strong muscles with this exercise. However,
there is a sufficient stimulus when the expanders are used properly and
for multiple sets and repetitions, to avoid muscle loss during short
periods of time when it is impossible to train with resistance
equipment. It's also a great way to burn some calories, increase muscle
endurance, get a great pump and increase your muscle tension between
workouts. When you are traveling, the expanders will take up very
little room in a suitcase.
References
Study of shoulder
rehabilitation exercises. Clin.Orthop. 179-188. Hintermeister, R. A.,
Bey, M. J., Lange, G. W., Steadman, J. R., & Dillman, C. J.
(1998a). Quantification of elastic resistance knee rehabilitation
exercises. J.Orthop.Sports Phys.Ther. 28, 40-50.
Hintermeister, R.
A., Lange, G. W., Schultheis, J. M., Bey, M. J., & Hawkins, R. J.
(1998b). Electromyographic activity and applied load during shoulder
rehabilitation exercises using elastic resistance. Am.J.Sports Med. 26,
210-220.
Hughes, C. J., Hurd, K., Jones, A., & Sprigle, S.
(1999). Resistance properties of Thera-Band tubing during shoulder
abduction exercise. J.Orthop.Sports Phys.Ther. 29, 413-420.
McCann, P. D., Wootten, M. E., Kadaba, M. P., & Bigliani, L. U. (1993). A kinematic and electromyographic
Simoneau,
G. G., Bereda, S. M., Sobush, D. C., & Starsky, A. J. (2001).
Biomechanics of elastic resistance in therapeutic exercise programs.
J.Orthop.Sports Phys.Ther. 31, 16-24.
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