The Spine 129which use of a neutral pelvis is advocated, use of a
slight posterior pelvic tilt when one is first learning
long lever arm exercises can help ensure that lumbar
hyperextension is avoided (figure 3.43B). To further
reduce risk, such exercises can initially be performed
on the forearms with only one leg extended (table
3.4G [p. 136], leg reach), with the legs pointing up
more toward the ceiling or with the knees bent such
that the torque produced by the legs will be less, or
with the hands or a pillow under the pelvis so that
a better angle of attachment for the abdominalmuscles facilitates the ability to stabilize
the pelvis.
Similarly, if leg lifts are advanced for
highly conditioned dancers to variations
where the torso is vertical (at a gym
or with the Pilates Cadillac as seen in
figure 3.44A), one or both knees should
be initially bent to reduce the torque
produced by the legs while adequate
abdominal stabilization strength and
skill are developed. Then, over time,
one or both legs can be partially and
eventually fully extended, only as long
as adequate stabilization of the lumbar
spine can be maintained (figure 3.44B).
Changing the relationship to gravity such
that the moment arm of the resistance
(represented by the legs) gets longer as
the legs are lifted to 90° (versus shorter
as occurs with the supine version) makes
the abdominals have to work much harder.
Hence, the hanging leg lift (in contrast to
supine variations) has been shown to be
one of the most effective abdominal exer-
cises for recruiting the obliques as well as
the rectus abdominis (Axler and McGill,
1997; Flint and Gudgell, 1965; Guimaraes
et al., 1991; Gutin and Lipetz, 1971).General Guidelines
for Back Extensor StrengtheningIn the past it was believed that lumbar
hyperlordosis posture and much of back
injury were due to a strength imbalance,
with the abdominal muscles being weaker
than the back extensors. Hence, the
emphasis was primarily on strengthen-
ing the abdominal muscles. However, in
recent years this theory has been chal-
lenged. There is increasing evidence
that many individuals are weak in their
back muscles as well as their abdominal
muscles (Graves et al., 1990; Pollock et al., 1989;
Smidt et al., 1983; Suzuki and Endo, 1983), and
the tightness of the low back commonly seen with
lumbar hyperlordosis is not necessarily indicative
of high strength levels. Furthermore, it has been
shown that inadequate spinal extensor strength and
endurance can increase the risk for low back injury
(Caillet, 1996; Parnianpour et al., 1988) and that
both inadequate extensor strength and, particu-
larly, inadequate endurance are commonly present
in individuals with low back pain (Chaffin, 1974;FIGURE 3.43 Long lever arms. (A) Inadequate abdominal stabilization
resulting in the iliopsoas pulling the lumbar spine into hyperextension and
undesired low back stress, (B) adequate abdominal stabilization with a slight
posterior pelvic tilt.