112 Dance Anatomy and Kinesiologyspinal extensors on the opposite side in the lumbar
region but greater activity in the spinal extensors
on the same side in the thoracic region (Andersson,
Ortengren, and Nachemson, 1977).Spinal Rotation
Spinal rotation is twisting around the long axis of the
spine and, similar to the situation with lateral flexion,
is also designated as right or left in accordance with
the way the front of the upper spine turns with refer-
ence to the lower part. Right rotation is defined as
movement of the head or shoulders to the right with
respect to a fixed pelvis, or movement of the pelvis to
the left with respect to a fixed head or fixed shoulders
or upper spine. Return from these positions would
be termed left rotation.
Concentric contraction of the spinal rotators is
used whenever the head, torso, or pelvis is twisted
such as in jazz isolations, spiral movements in
modern dance (figure 3.35), and facings in ballet
where the front of the torso is rotated relative to the
front of the pelvis. For purposes of simplicity, this
discussion will be limited to thoracic and lumbarrotation. Performing rotation around the long axis of
the spine would be affected primarily by the abdominal
obliques and spinal extensor muscles. Theoretically
when rotating the torso to the right, the right internal
oblique, right longissimus, right iliocostalis, left exter-
nal oblique, left multifidus, left rotatores, and left semi-
spinalis thoracis muscles would contract to produce the
movement. Note that unlike what happens in lateral
flexion, the internal and external obliques from oppo-
site sides work together to produce rotation.
While some EMG studies have confirmed this
expected activity in the lumbar region (Ortengren
and Andersson, 1977), other studies have shown
a more complex contribution of muscles than
expected, possibly due to the complex interaction
of agonists, synergists, antagonists, and stabilizers
and the complex lines of pull and multitude of
joints crossed by spinal musculature (Basmajian and
DeLuca, 1985). Also, as with lateral flexion, position-
ing of the torso and the relationship of gravity will
affect which muscles contribute, as well as the pri-
mary site of rotation. For example, when spinal rota-
tion is performed from a vertical standing position,
greater rotation tends to occur in the thoracic region.
However, when it is performed from a posi-
tion of hyperextension, a greater amount
of rotation tends to occur in the lumbar
spine, and the spinal extensors tend to
make a larger contribution to the desired
rotation. Conversely, when spinal rotation
is performed from a position of spinal
flexion, greater rotation occurs higher
in the spine, and the oblique abdominals
tend to be utilized more to produce the
rotation. These same concepts apply to
strengthening exercises with rotation in a
prone position.Key Considerations for the Spine in Whole Body Movement
Due to its central location, coordinated
movement between the trunk and limbs is
vital to meet movement goals and for injury
prevention. Core stability is one important
mechanism for protecting the spine and
enhancing centered movement.Core Stability
Core stability (also referred to as trunk sta-
FIGURE 3.35 Sample dance movement showing spinal rotation. bility, lumbopelvic stabilization, and spinal
© Angela Sterling Photography. Pacific Northwest Ballet dancer Christophe Maraval.