Dance Anatomy & Kinesiology

The Spine 131

pelvis down to help prevent excessive anterior tilting
of the pelvis and reduce excessive hyperextension in
the low lumbar area.

Upper Back Emphasis. Given the markedly greater
range of hyperextension possible in the lumbar
region and the larger cross-sectional area of the
spinal extensors in this region, it is easy for back
extension exercises to primarily challenge and
strengthen the low back region. However, since there
are actually different muscles (e.g., the semispinalis)
and different slips of muscles in the thoracic region
than in the lumbar region, it is important to also
include exercises that emphasize strengthening the

upper back. One way to achieve this is to select posi-

tions such as sitting (e.g., scarecrow, table 3.4H [p.

137]) or kneeling over a ball (e.g., kneeling scare-

crow, table 7.10H [p. 439]) where the abdominals

can be used to more readily keep the lumbar spine

in slight flexion, as extension higher in the spine is

emphasized. However, because the thoracic curve is

concave anteriorly, it is important to note that the

range of extension will be very small compared to

that which occurs in the lumbar spine.

Type of Muscle Contraction. As with the abdominals,

the arms can be used (in this case to press down on

the ground when prone) to achieve a slightly greater

Back Extensor Strength Test

Perform the following test on another dancer to estimate the strength of the back extensors. This

test should be performed slowly, carefully, after the back is fully warmed up, and only if it is pain

free. Dancers with a history of back injury or pain should not perform this test unless approved and

supervised by their medical provider.

Back Extension Height Test (Muscular Strength)

Start with your partner prone on a mat with the knees extended and the feet together and resting on

the ground. The elbows are bent with the fingers spread and lightly resting on the back of the head.

Then, have your partner, with the elbows back behind the ears, very slowly arch up as high as possible

without using momentum, without letting the elbows come forward, and without letting the feet lift off

the ground. Cue your partner to arch the spine starting from the top of the spine and continuing to

the bottom. Measure the perpendicular distance from the indentation at the base of the neck (sternal

notch) to the ground using a tape measure as shown in the figure. The goal is to be able to come up

to the same height with this active test as the dancer can achieve passively (when using the arms

to press against the floor to arch the back). Average back extension test results for performing arts

high school dance majors tested by the author were 13 inches (33 centimeters) for female and 12

inches (30 centimeters) for male dancers.

Note: Due to differences in spine length and flexibility, the same measured distance will not reflect

the exact same angle of spinal extension from individual to individual. However, this measure will

give you an approximate indication of strength (with stronger individuals able to come up higher) and

provides a useful tool to monitor improvement in strength within the same individual.

TESTS AND MEASUREMENTS 3.4

http://www.ebook3000.com