Dance Anatomy & Kinesiology

406 Dance Anatomy and Kinesiology

than 30°) is accompanied by upward rotation of the

scapula (serratus anterior and trapezius); and full

abduction to an overhead position is not possible

without this coordinated upward rotation of the

scapula. The rotator cuff also contributes by helping

depress the head of the humerus (SIT force couple:

subscapularis, infraspinatus and teres minor) to

prevent impingement in middle ranges of abduction

and help counter potentially superiorly dislocating

components of the force produced by the middle

deltoid in higher ranges of abduction (Hall, 1999).

In higher ranges of abduction, the rotator cuff also

can produce slight external rotation (infraspinatus

and teres minor) to help clear the greater tubercle

relative to the acromion process and allow greater

range of the arm.

Shoulder Adduction

In open kinematic chain movements, shoulder

adduction involves moving the arm downward

and inward toward the midline of the body from

an abducted position in approximately the frontal

plane, such as in bringing the arms from second to

low fifth. However, when the torso is upright, gravity

will tend to produce this movement, and shoulder

adduction and its associated downward rotation are

generally controlled by eccentric contraction of the

shoulder abductors and scapular upward rotators.

However, if the arms are brought beyond anatomi-

cal position in front of or behind the body where

the motion is now against gravity as shown in figure

7.29 (left shoulder “hyper”adduction combined with

slight shoulder flexion), or if the motion is opposed

by another external resistance such as a weight appa-

ratus (e.g., lat pull-downs), elastic tubing, water (e.g.,

swimming the breaststroke), or another dancer, the

shoulder adductors and scapular downward rotators

(rhomboids, levator scapulae with lower trapezius or

serratus anterior to neutralize elevation) come into

play. Similarly, in closed kinematic chain movements

such as the iron cross in gymnastics, the shoulder

adductors would be used concentrically against

gravity to raise the body. Unlike what occurs at the

hip, where there is a specific muscle group that pro-

duces hip adduction, at the shoulder there are not

specific muscles whose primary function is shoulder

adduction. Instead, muscles located on the front and

back of the shoulder are simultaneously contracted

to produce shoulder adduction. For example, com-

bined contraction of the pectoralis major and latis-

simus dorsi results in shoulder adduction, as would

combined contraction of the anterior and posterior

deltoid muscles.

FIGURE 7.29 Sample dance movement showing shoul-

der adduction.

Photo by Edward Casati. Alonzo King’s Lines Ballet dancer Maurya Kerr in “Baker

Fix,” dress by Colleen Quen Couture.

FIGURE 7.28 Sample dance movement showing shoulder abduction.
Photograph by Brooks Dierdorff. Dancer: Nicole Robinson.