132 Dance Anatomy and Kinesiology
height of the torso (e.g., greater spinal extension)
than can be achieved with a concentric contraction.
This higher position can be held for several counts
(isometric contraction) or followed immediately with
a controlled lowering (eccentric contraction) to the
prone starting position. However, particular care must
be taken not to strain the back extensors by only going
a few degrees higher than can be reached concentri-
cally, and starting by only sliding one arm out as the
other arm still offers support.Spinal Rotation. Adding rotation to back extension
exercises can add greater overload to the muscles
that produce rotation in the desired direction. Fur-
thermore, because there are actually different spinal
extensor muscles and slips of muscles in different
regions of the spine, rotation in different regions and
positions of the spine can actually produce greater
challenge to different muscles. For example, pure
rotation was found to elicit a marked response in the
multifidus and rotatores while the iliocostalis showed
greater activity when forward flexion (from standing)
was combined with rotation (Basmajian and DeLuca,
1985). In prone or kneeling positions, subtle rotations
and stabilizations, similar to those used in dance, can
be effected by lifting one arm, one leg, or an arm and
a leg at the same time (e.g., prone arabesque, table
3.4N [p. 140]. When on the hands and knees, lifting
the opposite arm when one leg is lifted increases the
upper erector spinae activity by about 30% (Levangie
and Norkin, 2001).Adequate Overload and Recovery. As with the
abdominals, to produce desired improvements in
muscular strength, the exercises that are performed
should be difficult enough that only about 12 or
fewer repetitions can be performed, and a 2- to 3-
minute recovery of the spinal extensors should be
allowed between sets of back extension exercises.
Difficulty can be increased by using a larger range
of motion, adding rotation, bringing the arms to
the side or overhead versus down by the sides, and
adding dumbbells in the hands for resistance. Since
the effect of gravity on the body is primarily creat-
ing the resistance in many back extensor exercises,
appropriate body positioning should be used so
that the torso or pelvis is moving against gravity to
produce spinal extension, such as when performing
prone back extensions (e.g., table 3.4I [p. 138]).Technique and Kinesthetic Awareness. Performing
back extensor exercises in a smooth and controlled
versus jerky manner with precise spinal articulation
and positioning of the pelvis is essential for effec-
tiveness and safety. Subtle stabilization skills andkinesthetic awareness must be developed to achieve
the desired sequential extension of spinal vertebrae
rather than having large segments of the spine move
as a whole or almost all of the movement occur in
the low lumbar spine. Lack of adequate stabilization
can make many back exercises potentially injurious
rather than therapeutic.Limiting Back Extensor Exercise Risk
Unfortunately, applying many of the principles that
increase effectiveness, such as the addition of rota-
tion and resistance, will also increase the stresses
borne by the discs and other spinal structures. So a
more conservative approach is often recommended,
with particular attention paid to range of motion
and stabilization.
Range of Motion. Using a greater range of motion
produces more overload through shortening of the
muscles and allows for development of strength
through a full range of motion. However, greater
range of motion will generally require marked spinal
hyperextension, which is of concern in terms of injury.
Hence, there is still controversy as to how much range
of motion should be used in back extension exercises.
For dancers with access to a gym (roman chair),
exercise ball, bench, or Pilates barrel, this controversy
can be avoided by performing back extensions from
a position of flexion to just a straight (neutral) spine.
And one study showed marked gains in back extensor
strength in a flexed to neutral position when train-
ing on exercise equipment in a relatively small arc of
36° flexion (Graves et al., 1990). However, because
of the prevalent use of marked spinal hyperexten-
sion in dance, there is a theoretical basis in terms of
functional issues to support using a range of motion
in strength training for dances that includes hyper-
extension. And only studies that have linked back
strength to the demands of the job have shown the
ability to predict future back injuries (Parnianpour
et al., 1988). But to reduce injury risk, hyperexten-
sion should only be performed (without medical
supervision) if no back discomfort is present, there
is no history of back pain or medical contraindica-
tion, range is gradually developed over time, and
sound technique is employed. One approach is to
initially limit hyperextension to about 10 or 20° while
focusing on developing abdominal co-contraction/
stabilization skills. Then range can be gradually
increased as long as appropriate stabilization is used
and the movement remains pain free.
Abdominal Co-Contraction. One important aspect of
these stabilization skills is utilizing a co-contraction
of the abdominals, as discussed under Spinal Hyper-