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Muscle: Biceps brachii, short head
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Origin: At the tip of the coracoid process of
the scapula.
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Insertion: At the radial tuberosity
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Function:
Flexor of the elbow, strong supinator and has a
weak flexion effect on the shoulder (because it is
biarticular- crosses both the shoulder and elbow
joints).
-
-
Muscle:
Biceps brachii, long head
-
Origin: At the supraglenoid tubercle of the
scapula
-
Insertion: At the radial tuberosity
-
Function: Flexor of the elbow, strong
supinator and has a weak flexion effect on the
shoulder (because it is biarticular- crosses both
the shoulder and elbow joints).
-
-
Muscle: Brachialis
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Origin: At the anterior lower half of the
humerus
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Insertion:
At the ulnar tuberosity
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Function:
Flexor of the elbow (uniarticular), regardless of
whether the arm is supinated or pronated (since the
ulna does not rotate)
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Indications of Weakness
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Biceps weakness is indicated when the arm hangs excessively
straight or is hyperextended. This weakness may also
make it difficult to supinate the forearm when the
arm is moving into flexion.
-
Brachialis or biceps that have shortened will make
full arm extension or supination difficult. This
will impair strength and muscular development.
Triceps strength can also decrease if the biceps has
shortened and is hypertonic because of the agonist
antagonist relationship.
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Optimal Training Principles
-
To
develop optimum size and strength of the bicep
muscle group, will require a variety of barbell,
dumbbell and cable exercises to work the various
parts of the muscle.
-
Straight barbells keep the arm neutral. Curling bars
keep the arm slightly pronated. Dumbbells and cables
allow for adjusting and maximizing supination.
-
The
preacher curl emphasizes the first part of elbow
flexion.
-
The
standing barbell curl stresses the midrange of
biceps flexion.
-
The
concentration curl stresses the last range of biceps
flexion.
-
Variation of these 3 ranges are essential to
optimize muscle fiber stress to increase biceps
size, biceps strength and biceps function through a
full ROM.
-
In
any biceps curl, it is important to fully extend the
arm before starting the next repetition. The
prestretched position of the biceps stresses the
muscle through its full ROM. Use caution to make
this a controlled, gentle stretch to avoid damage to
the muscle, tendon, and ligaments of the elbow joint
capsule, from uncontrolled hyperextention!
-
Keeping the elbows in front of the body, as is
typical of barbell and dumbbell curls, will stress
the brachialis and short head of the biceps and
reduce stress on the long head of the biceps.
-
The
long head is stressed more when the arm is behind
the body, as in an incline dumbbell curl, which is
an excellent exercise to increase both its size and
strength.
-
Many bench-press shoulder injuries are caused by
weakness in the long head of the biceps. This can be
determined by a functional muscle test.
-
Long head biceps curl: Perform regular bicep
curl to full flexion and then raise the elbows to
shoulder height while maximally contracting the
biceps.
-
The
brachialis muscle lies between the biceps and
triceps and can be seen on the outer side of the
developed arm.
-
Reverse curls with barbells, curling bars or
dumbbells and Hammer curls (hands semipronated:
thumbs-up) increase stress on the brachialis. The
biceps is 20-30% weaker in pronation, this position
will increase the size, strength and function of the
brachialis.
-
Biceps supination is best done just before the elbow
is at 90 degrees of flexion during a dumbbell curl.
If supination starts when the arm is at the side,
the supinator muscle in the anterior elbow joint
does most of the work, decreasing the stress on the
biceps muscle.
-
David Gorman states that the strength of the biceps
varies with the position of the arm relative to the
shoulder:
-
Chin-up: Arm is above the shoulder: flexion strength is 183
pounds (83 kilograms)
-
Horizontal Preacher Curl: Arm is level with the shoulder:
flexion strength is 146 pounds (66 kilograms)
-
Barbell Curl: Arm is below the shoulder: flexion strength is
115 pounds (52 kilograms)
-
Notice that the strongest flexion strength is in the
chin-up position. This is one of the better biceps
exercises if the person is strong enough to pull up
his or her body weight. If not, Gravitron machines
or Bicep Pull Downs on the lat-machine can be used
to increase size, strength and function.
More
Books from Jim Bell, PhD.c.
