Dance Anatomy & Kinesiology

270 Dance Anatomy and Kinesiology

have adequate time to counter the increased loads

placed on the knee (Besier, Lloyd, Ackland, and

Cochrane, 2001). It is likely that dancers who train

regularly will develop strategies for standard dance

vocabulary that will help minimize the stress to the

knee ligaments.

Hyperextended Knees in Dance

When the body is standing erect, the gravity line

falls slightly in front of the knee joint axis, leading

to a “locking” of the knee in extension by a small

gravitational torque. This locking is also due to the

terminal rotation associated with full knee extension

previously discussed (e.g., the locking mechanism

of the knee). Because this end position is passive

and does not involve contraction of lower extrem-

ity muscles, dancers with genu recurvatum will not

exhibit the same passive endpoints, and the knees

will not stop at extension but rather will continue

to a position of hyperextension (figure 5.27A).

Hyperextended knees are very prevalent in dancers,

and one study (Trepman et al., 1994) showed that

all of the dancers studied exhibited knee hyperex-

tension when standing in turned-out first position,

but with significantly greater magnitude in ballet

than modern dancers (average of 13° vs.

5°). However, even dancers with extreme

hyperextension can learn to control the

extent of hyperextension allowed both in

standing and in dance movements.

Two tactics for controlling knee hyper-

extension in dance include (1) limiting the

degree of knee extension and (2) limiting

the degree of femoral internal rotation.

The first approach relies on the principle

of stopping the knee earlier as it extends,

when the center of mass of the whole body

is just over the axis of the knee joint rather

than anterior to the knee joint, so that

passive knee hyperextension is avoided.

Sometimes cueing to do just this, that is, to

simply not straighten the knees so far or to

“pull the knees straight up” versus “push-

ing the knees back,” may be sufficient to

prevent the problem. Similarly, thinking of

“pulling up” just below the back of the knee

at the same time that the front of the knee

is being “pulled up” can encourage co-con-

traction of the hamstrings and quadriceps

femoris. Since the hamstrings are flexors of

the knee, if recruited early enough when

the knee is still slightly bent, they can be

used to prevent excessive knee extension.

Alternatively, keeping the knees farther forward, in

front of the ankle, as they are straightened can also

prevent the center of mass of the body from moving

anterior to the axis of the knee where it will tend to

produce knee hyperextension.

The second approach relies on the linking of femo-

ral internal rotation with hyperextension of the knee.

Since the final ranges of knee extension naturally

incorporate internal rotation of the femur due to the

locking mechanism of the knee, focusing on using the

external rotators at the hip to limit this internal rota-

tion of the femur and keep the knees facing directly

forward rather than twisting inward can prevent unde-

sired knee hyperextension. Excessive internal femoral

rotation can also be avoided by focusing on “pulling

up” with the abdominal muscles while bringing the

bottom of the pelvis forward to create a neutral pelvis,

so that the femoral internal rotation associated with

an anterior tilt of the pelvis is avoided.

However, with whichever method is used, since the

hyperextended position will “feel straight” to a dancer

who is used to hyperextending the knees, this new

position will often feel as though the knees are bent.

Often a mirror and visual correction must be used

initially by the dancer until the internal sensation of

“straight” is relearned.

FIGURE 5.26 Potential valgus stress of can be reduced by allowing the
right ischial tuberosity to lift slightly off the floor.