The Spine 113stabilization) can be defined as the development or
restoration of neuromuscular aspects of lumbopelvic
control vital for protecting the spine from injury
or reinjury (Hodges, 2003). Strategies to develop
core stability generally utilize two components. One
component emphasizes utilizing exercises to improve
the muscular strength and endurance of key trunk
muscles (muscle capacity). The second component
has gained great attention in recent years and focuses
on the training of the coordinated use of these key
trunk muscles during functional movements (motor
control).
As described earlier in this chapter, the vertebral
column is very dependent on a balance of the spinal
muscles for stability. Unlike some joints such as
the hip and knee, which can be “locked” in slight
hyperextension to allow the ligaments to provide
the primary support, the spine cannot be locked and
the anterior-posterior curves of the spine will tend to
collapse or buckle due to the effect of gravity if not
counterbalanced by appropriate muscles. In fact, an
isolated ligamentous spine without muscular support
will collapse when less than 5 pounds (2 kilograms)
is applied to it (Nachemson, 1966). The torso can
be pictured as a cylinder (Nachemson and Morris,
1964), where with ideal alignment muscles located
on all sides of the cylinder are balanced so that the
torso is “stable,” the curves are not exaggerated, and
the spine is protected from excessive stress.
Many muscles of the trunk likely play a role in
core stabilization, but due to their location the
abdominals and back extensors are particularly key.
For example, automatic abdominal contraction
(transverse abdominis followed by oblique abdomi-
nals) prior to quick movements of the arms, and
legs, peak vertical forces in walking and running,
and landing from jumping has been demonstrated
(Grillner, Nilsson, and Thorstensson, 1978; Hodges
and Richardson, 1996, 1997). Studies suggest that the
central nervous system activates components of the
abdominals without our conscious awareness prior
to movement of the limbs. This precontraction of
the abdominals is believed to aid with trunk stability
through the resultant generation of IAP or thoraco-
lumbar fascia tensioning. Similarly, muscles such as
the multifidus of the deep posterior spinal group
appear to be vital for core stability at the segmental
level of the spine. So, well-timed and coordinated
contraction of such deep muscles of the spine is
believed to be particularly key for stabilizing the
spine on a segmental level, while the more superficial
trunk muscles that can generate larger forces work
to stabilize and control movements of the spine as
a whole. Together, these deep and superficial trunk
muscles can be used to lessen or eliminate unde-
sired compensatory trunk movement occurring in
response to movements of the limbs and could lessen
potentially injurious forces borne by the spine.Centered Movement
Core stability is also one important aspect of highly
skilled movement used by dancers and athletes. In
movement forms such as dance, martial arts, and
Pilates, use of core stability is one part of desired
movement patterns that are often termed “cen-
tered” movement. In these movement forms, core
stability is often used in a very refined manner to
meet aesthetic goals as well as biomechanical goals.
For example, in some dance movements, the torso
and pelvis are held relatively upright while the arms
or legs are used in a variety of movements. Many
beginning dancers have difficulty with this coordina-
tion, and many visible compensations of the torso
leaning front, side, or back are seen. However, as
skill progresses, such compensations are minimized
such that large range limb movements occur without
distorting the desired positioning of the torso. This
skill is made more complex in cases where the torso
is moved through desired positions off the verti-
cal while the limbs move. For example, the spinal
hyperextension accompanying a cambré to the back
in ballet, the presentation of the torso in flamenco,
a jazz layout, or a spiral arching motion of the torso
used in modern all require slightly different use of
the abdominals, back extensors, and other trunk
muscles to create the desired line and avoid exces-
sive movement of one vertebra relative to another.
Achieving and maintaining such desired positions of
the torso not only requires strong trunk muscles but
also appropriate timing and magnitude of activation
of these muscles.Special Considerations for the Spine in Dance
Various aspects of dance place great demands on the
spine. Some areas that are of particular importance
in terms of technique and injury prevention are
spinal alignment, spinal hyperextension, standing
forward flexion, and partnering.Spinal Alignment in Dance
The standing alignment used at center floor or at the
barre in some dance styles is quite similar to the ideal
standing alignment previously described. However,