The Knee and Patellofemoral Joints 271Knee Hyperextension
and Genu VarumWhen genu varum is present, allowing the knees
to hyperextend can increase the distance between
the knees, giving the leg a more “bowed” look. In
contrast, using the approaches just described to
correct knee hyperextension—so that the knees are
farther forward relative to the ankles and the knees
face forward rather than inward as the inner thighs
(hip adductors) are slightly contracted to pull the
legs “together and up”—can help minimize the dis-
torted appearance of genu varum. And over time,
some dancers appear to be able to reduce apparent
genu varum.Overdevelopment of the Quadriceps
In some dance forms such as ballet, there is the
desire to develop the body so that the legs appear
“long”; and “short, thick, overdeveloped” thighs are
avoided. Although genetics, body type, and limb
length contribute to the appearance of the thighs,
and dancers are encouraged to embrace the body
type they have, training can also influence this devel-
opment. While some hold that thigh development is
simply related to the amount of quadriceps stress oroverload and resultant increase
in size (hypertrophy), others
conjecture that other factors
such as the type of muscle con-
traction (higher emphasis on
concentric vs. eccentric), speed
of muscle contraction, or the
range of motion utilized by the
sport may also influence subtle
differences in muscle develop-
ment. In the dance arena, many
dancers’ bodies can change to
develop a “longer,” less “bulky”
look after training at schools
that emphasize this aesthetic.
Further scientific investigation
into this area is warranted, but
two possible mechanisms for
decreased thigh development
are movement economy and
altered muscle recruitment
patterns.
In terms of movement econ-
omy, dancers with marked thigh
development sometimes appear
to be using excessive effort
with movement, sometimes
described by dance teachers as “gripping” or “work-
ing tensely.” In contrast, dancers with the desired
“long” muscle sometimes appear to be working more
economically, without apparent wasted effort. Two
examples of these extremes are shown in figure 5.28,
where the execution of a second-position plié was
associated with 25% versus 125% of a maximum iso-
metric quadriceps contraction in a highly skilled ballet
dancer noted for her “long lines” (figure 5.28A) versus
a less skilled dancer noted for working with excessive
“gripping” (figure 5.29B). Considering the marked
difference in muscle effort associated with perfor-
mance of the same movement, one could theorize that
the second dancer would have greater hypertrophy
of the quadriceps from dance training. This concept
of greater economy being associated with skill level
was given further support by another study that
found significantly lower levels of activation of the
rectus femoris and biceps femoris in key phases of a
turned-out demi-plié in more experienced dancers
(Ferland, Gardiner, and Lèbé-Neron, 1983).
In terms of altered muscle recruitment patterns,
it may be that dancers with greater thigh develop-
ment recruit the quadriceps femoris more in various
dance movements. This might relate to alignment
issues such as positioning of the torso or the amount
of turnout used at the hip. For example, leaningFIGURE 5.27 Knee hyperextension. (A) Standing with the heels separated and knees
hyperextended; (B) correction of knee hyperextension, allowing the heels to be brought
closer together.