Dance Anatomy & Kinesiology

150 Dance Anatomy and Kinesiology

loading), and a much higher incidence is found

in athletes who are involved in activities requiring

repetitive use of such hyperextension such as danc-

ers, gymnasts, weightlifters, football linemen, divers,

and figure skaters (Eck and Riley, 2004; Fehlandt and

Micheli, 1993; Kotani et al., 1970; Seitsalo et al., 1997;

Trepman, Walaszek, and Micheli, 1990). For example,

while the incidence of spondylolysis in the general

U.S. population is about 5% (Deckey and Weiden-

baum, 1997), incidence of spondylolysis was found

to be about six times greater (32%) in one study of

professional ballet dancers (Seitsalo et al., 1997).

Spondylolysis is of particular concern with young

dancers. One study comparing athletic teens to adults

with low back pain showed an incidence of spondyloly-

sis of 47% in teens as compared to only 5% in adults

(Micheli and Wood, 1995). Some other studies have

shown less dramatic, but still markedly increased,

incidences of spondylolysis in young athletes and

particularly in athletes who participate in sport for

more than 15 hours per week (Hall, 1999).

A closely aligned condition to spondylolysis is

spondylolisthesis. Spondylolisthesis (G. spondylo,

vertebra + olisthesis, slipping) involves an actual slid-

ing forward of one vertebra on the vertebra below,

usually secondary to having spondylolysis on both

sides (figure 3.48B). It most commonly occurs in the

lumbar spine, with L5 slipping on S1 being the most

common, followed by L4 slipping on L5 (Weiker,

1982). Spondylolisthesis can be classified according

to the amount of forward displacement of the supe-

rior vertebra relative to the width of the vertebral

body below as seen in figure 3.48C: 1 reflects up to

25% slippage; 2 indicates greater than 25% and up

to 50%; 3 reflects greater than 50% and up to 75%;

and 4 reflects greater than 75% slippage (Mercier,

1995). Logically, greater slippage is of greater con-

cern in terms of spinal stability, symptoms, prognosis

for return to dance, and potential need to stabilize

the spine with a surgical procedure.

Symptoms of spondylolysis or spondylolisthesis

include low back pain that is often exacerbated by

hyperextension, particularly during standing on one

leg (such as an arabesque). Tenderness directly on

the spine (in contrast to the muscles on the sides of

the spine) is often present, and in some cases there

may also be radiating pain down the buttocks and leg

(sciatica), and tightness in one hamstring. With spon-

dylolisthesis, a “step-off” or “ledge” can sometimes be

felt due to the forward displacement of the lumbar

spinous process where the vertebra has slid forward.

Although the prevalence of spondylolysis in dancers

is high, it is important to be aware that many dancers

with spondylolysis or lower grades of spondylolisthesis

are able to continue successful dance careers, and

some may not even have pain (Deckey and Weiden-

baum, 1997; Seitsalo et al., 1997). When traumatic

spondylolysis is detected soon after its occurrence,

medical treatment including immobilization with anti-

lordotic bracing will often allow healing (Herman,

Pizzutillo, and Cavalier, 2003; Micheli, 1983). In other

cases, dancers are able to use abdominal co-contrac-

tion (Moeller and Rifat, 2001) and technique modifi-

cation sufficiently to limit shear and symptoms.

FIGURE 3.48 Spondylolysis and spondylolisthesis (lateral view). (A) Spondylolysis, (B) spondylolisthesis, (C) spondylo-

listhesis with amount of slippage graded 1 to 4.