Dance Anatomy & Kinesiology

402 Dance Anatomy and Kinesiology

and neutralize undesired secondary actions of the

prime movers. In addition, due to the large range

of motion possible at the shoulder, some muscles

may change their relationship to the axis of motion

at the shoulder joint, and hence their function, in

different ranges of motion. For simplicity, this section

will emphasize providing examples of the primary

muscles capable of producing the desired shoulder

movement and accompanying scapular movement(s).

However, readers are encouraged to remember that

this presentation represents a great simplification, that

many other stabilizers and synergists would actually

be operative, and that specific movement conditions

such as speed and resistance would influence which

muscles actually were recruited.

Shoulder Flexion

In open kinematic chain movement, shoulder flex-

ion involves bringing the arm forward and upward

relative to anatomical position in an approximate

sagittal plane, such as when raising both arms for-

ward from low fifth to high fifth positions or raising

one arm forward from a low to an overhead position

(right arm in figure 7.26). This same motion (con-

centric shoulder flexion) is used in strengthening

exercises such as the front arm raise (table 7.10B,

p. 434) and the kneeling biceps lift (table 7.10M, p.

442). The shoulder flexors are used concentrically in

walking and running when the arms swing forward,

in underhand throwing, in some underhand swings

in racket sports, and in bowling. Concentric shoulder

FIGURE 7.26 Sample dance movement showing shoul-

der flexion.

Photo courtesy of Myra Armstrong. Dancer: Lorin Johnson with American Ballet Theatre.

Upward rotation

FIGURE 7.25 Example of scapular synergy ideally

utilized during shoulder abduction.