The Spine 115arching” of the upper back, while some schools of
modern dance prefer slightly anterior positioning
of the rib cage. Skilled dancers can learn to achieve
these aesthetics while still protecting their low backs
with abdominal co-contraction. And as with the neu-
tral base alignment, skilled dancers should be able to
quickly reestablish the base alignment of their dance
style when demanded by the choreography.
When sitting on the floor as is common in modern
and jazz dance, a different challenge for spinal align-
ment comes into play. Sitting in a relaxed/slumped
position as seen in figure 3.36B tends to be associ-
ated with as much as 40° of posterior tilting of the
pelvis, with a consequent decrease in lumbar lordosis,
increase in thoracic kyphosis, and associated increase
in intradiscal pressure. It is very easy to assume this
position, as it relies on passive support from back
ligaments and other soft tissues with little spinal
extensor activity. However, using a more erect posi-
tion during sitting so that a more neutral position of
the pelvis is maintained and the weight of the upper
body is felt directly over the bottom of the pelvis
(“sitz bones” or ischial tuberosities) versus behind,
and so that the spinal extensors are used to “lift” the
spine and prevent excessive flexion of the lumbar
and thoracic regions, will reduce lumbar stress and
better achieve the desired dance aesthetic (figure
3.36C). When one is performing floor work in which
the knees are extended, it is important to realize that
adequate hamstring flexibility will be necessary to
allow this more neutral position of the pelvis, and it
may be necessary to slightly bend the knees to allowthis positioning in individuals with tight hamstrings
(see chapter 4).
In more complex dance movements, spinal align-
ment becomes much more complicated. However,
even though changes in positions are very dynamic,
there is still the desire to achieve a given movement
without undesired distortion of the spinal curves,
or in accordance with the specific positioning
dictated by the choreography. For example, when
one is performing a side reach, pure lateral flexion
involves the torso moving almost directly to the side
(figure 3.37A) without the ribs going forward or the
bottom of the pelvis going back (figure 3.37B). Such
positioning involves a subtle co-contraction of many
muscles with appropriate timing and magnitude of
force such that both appropriate spinal stabilization
and movement are effected in accordance with the
goal movement. Such coordination of muscles is one
marker of skill in the professional dancer.Spinal Hyperextension
Hyperextension of the spine tends to make the front
part of consecutive vertebrae pull away from each
other and the back part of consecutive vertebrae
press together. More specifically, hyperextension pro-
duces tension on the front of the disc, compression
at the back of the disc, and increased pressure within
the disc. Hyperextension also creates increased
stresses in the posterior portion of the vertebrae; and
when it is very forceful or repetitive, the facet joints
can become injured or stress fractures to the boneFIGURE 3.36 Changes in the low back with standing and sitting. (A) Normal lumbar curvature with standing, (B) unde-
sired excessive posterior tilt of pelvis and decreased lumbar lordosis with sitting, (C) desired neutral pelvic alignment
and less loss of normal lumbar lordosis with sitting.