Structure and
Function: Muscles of the Shoulder and Scapula
Nothing
stands out on something like a nice pair of deltoids (shoulders).
Whether the shoulders are large and wide or tight and toned, they are an
eye catcher. More important to the integrity of the shoulder joint
itself is the muscle deep to the shoulders, collectively called the
rotator cuff muscles. The trapezius also plays a role in shoulder
stability. We discussion will begin with the superficial deltoid
Deltoid
Like many
other muscles in the body, the deltoid is divided into distinct fiber
portions. The anterior deltoid originates from the lateral third of the
clavicle, the middle deltoid from the acromion process, and the
posterior deltoid from the spine of the scapula. All three portions of
the deltoid muscle insert on the deltoid tuberosity of the humerus.
Because the
three portions of the deltoid each pass over a different part of the
glenohumeral joint (shoulder), they each have a distinct action. The
anterior fibers flex and medially rotate the arm, the middle fibers
abduction the arm, and the posterior fibers extend and laterally rotate
the arm.
Rotator Cuff Muscles-
Supraspinatus, Infraspinatus, Teres Minor, and Subscapularis
The rotator
cuff aids in stabilizes the shoulder joint by holding the head of the
humerus in the glenoid fossa of the scapula. It is made up of four
muscles, all of which assist in the movements of the deltoid. Three of
the four muscles originate posteriorly, with only one originating
anteriorly.
Posterior Muscles—Supraspinatus, Infraspinatus, and Teres Minor
The most
superior of the three posterior rotator cuff muscles is the
supraspinatus. It originates from the supraspinous fossa of the scapula.
The infraspinatus originates from the infraspinous fossa of the scapula.
Finally, the teres minor originates from the lateral border of the
scapula. All three muscles insert on the greater tubercle of the humerus.
The
supraspinatus acts alone and assists in shoulder abduction. The
infraspinatus and teres minor on the other hand, work together as
lateral rotators of the arms. They also maintain the position of the
head of the humerus during other arm movements.
Teres
Major
Though the
teres major originates near the teres minor, its function is more
closely paired with latissimus dorsi due to its insertion. The teres
major originates from the inferior angle of the scapula and inserts on
the medial lip of the intertubercular groove of the humerus. The teres
major assist the latissimus dorsi in extension, adduction, and medial
rotation of the arm, but only when there is resistance against these
movements, such as during weight training.
Anterior
Muscles
Subscapularis
The only
anterior muscle of the rotator cuff is the subscapularis. The
subscapularis originates from the subscapular fossa of the scapula and
inserts on the lesser tubercle of the humerus. It is a medial rotator of
the arm. Of even greater concern is the subscapularis’ job of preventing
anterior dislocation of the head of the humerus.
Trapezius
The
trapezius is the easily distinguishable muscle superior muscle of the
neck/back, is divided into three different groups: the superior fibers,
middle fibers, and inferior fibers. Because of the many origins of the
trapezius, each of these areas of fibers performs a different action.
The trapezius as a whole originates from the external occipital
protuberance, ligamentum nuchae (the ligament of the back of the neck),
and spinous processes of the last cervical and all thoracic vertebrae.
All of these fibers insert on the lateral third of the clavicle,
acromion process and spine of the scapula.
As a whole,
the trapezius upwardly rotates the scapula. Individually, the superior
elevation the scapula, the middle fibers retraction the scapula, and the
inferior fibers depress the scapula.
Workout A
1. Military
Press 5 X 4-6
1. Barbell
Shrug 5 X 4-6
2. DB Rear
Delt Lateral 3 X 10
2. DB Shrug
3 X 10
Note:
Alternate exercises with the same number, resting 1-2 minutes between
each exercise.
Main
Focus: Increasing the weight lifting on military press and barbell
shrug
Military Press
The military
press is great for overall deltoid development, though it hits the
anterior delts the hardest. How far you bring the bar down is a personal
preference in my opinion. Some people will recommend stopping at your
nose, chin, and bringing the bar all the way down to your upper chest. I
say find what feels most comfortable for you.
Barbell Shrug
Heavy
barbell shrugs are great for trap growth. While emphasis should be
placed on lifting a heavy load, the load should not be so heavy that
your form and ROM suffers. As you shrug, think of trying to touch your
traps to your ears. This is how high up you should strive to shrug the
bar.
Rear Deltoid Lateral
The reason
why I included rear delt laterals in this program is the posterior head
of the deltoid is often underdeveloped in bodybuilders and this stems
from not directly working it. The posterior deltoids can be hit by doing
bent over DB lateral raises, bent over cable lateral raises, or rear
delt flies on the reverse pec dec.
The main
thing to focus on when trying to hit the rear delts is actually USING
the rear delts. You should be able to feel the rear delts contracted
with each rep. If you cannot, you are most likely using too much weight
and need to decrease it and increase your ROM. Using too much momentum
on bent over DB laterals will also cause you not to use the rear delts
to the full extent.
DB Shrug
DB shrugs allow you to use a
greater ROM than barbell shrugs, which can lead to the stimulation of
more muscle fibers.
Workout B
1. DB shoulder Press 3 X
6-10
1. Behind the Back Barbell
Shrug 3 X 6-10
2. DB Side Lateral 3 X 6-10
Super-setted with
1-Arm Cable Lateral 3 X
6-10
3. DB Shrugs done lying
Prone on Incline Bench 3 X 6-10
DB Shoulder Press
Like the
military press, the DB shoulder press is great for overall shoulder
development. This exercise is executed just like the military press
except the use of DBs makes each arm work independently.
Behind
the Back Shrugs
Behind the
back shrugs are done just like standard barbell shrugs but with the
barbell behind you. This change in position of the bar increases the
recruitment of the middle and lower fibers of the traps.
DB
Side Laterl and 1-Arm Cable Lateral
These
lateral raises target the middle deltoids. Increasing the size on the
medial delts will give your shoulders a round, full look. The key to
these exercises is not using momentum or your traps to lift the DBs and
pull the cables. You want to keep the tension on the medial delts. This
can be done by bending the elbows slightly and rotating your wrist so
your pinky is higher than your thumb (a trick used by Arnold
Schwarzenegger).
Prone DB Shrugs
Prone DB
shrugs done lying on an incline bench allow you to hit the middle and
lower fibers of the traps to a greater degree than the standard shrug.
Instead of shrugging the weight straight up when standing, you want to
squeeze the mid-back/traps together to lift the DBs on this exercise.
Derek
“The Beast” Charlebois is an ACE certified personal trainer, competitive
bodybuilder, and holds a Bachelor’s degree in Exercise Science from The
University of Michigan. Derek is the Promotions Coordinator/R&D at
Scivation/Primaforce and is involved in coordinating promotions,
research
and
development, advertising, and marketing. Derek is an accomplished author
with articles on such websites as Bodybuilding.com, Bulknutrition.com,
the online magazines StrengthAndScience.com and MusclesAndCuts.com, and
is a contributing author to the book Game Over:
The Final
Showtime Cut Diet You’ll Ever Need!
Derek is available for online personal training; personal training
inquiries can be sent to
derek@scivation.com. His website is
www.beastpersonaltraining.com.
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