274 Dance Anatomy and Kinesiology
of the pes anserinus group and tensor fasciae latae
were also described in this previous chapter on
the hip, while exercises for the gastrocnemius are
described in chapter 6.Knee Extensor (Quadriceps Femoris)
Strengthening
The knee extensors are very important antigravity
muscles that act to control the lowering of the body,
propel the body through space, or maintain an
extended position of the knee. Furthermore, ade-
quate quadriceps strength plays an important role
in knee joint stability, the prevention or progression
of knee osteoarthritis (Suter and Herzog, 2000), and
proper tracking of the patella. While some female
dancers are concerned about developing excessive
bulk in the quadriceps femoris muscles, adequate
strength is essential for injury prevention; and the
exercises in table 5.3 can generally be used to develop
strength without excessive bulk because the amount
of weight (resistance) and volume (number of sets
and reps) are generally too low to stimulate a large
increase in muscle size (hypertrophy).
The knee extension can be strengthened iso-
metrically by pulling the kneecap upward (quad
sets) or isotonically by resisting knee extension. For
dancers who have a history of kneecap problems or
who experience knee discomfort with grand pliés, it
is advisable to begin with exercises such as the quad
set (table 5.3A) and straight leg raise (table 5.3B) in
which the knee is isometrically maintained in a posi-
tion of extension so that patellofemoral compression
forces are low. Exercises incorporating only the final
20° to 30° of extension, such as the terminal knee
extension (table 5.3C) exercise, can also be useful
for providing greater overload to the quadriceps
while patellofemoral compression forces still remain
relatively low. However, for males without patellar
problems and females who have developed adequate
patellar stability and are pain free, performing knee
extension exercises utilizing a larger range of motion
(table 5.3D) is valuable to develop the strength
needed for demanding dance movements utilizing
greater degrees of knee flexion.
When one performs any of these extension exercises,
proper technique is important. Due to the prevalence
of knee hyperextension in dancers, it is important to
take care that the knee is brought only to a straight
position and not beyond straight to a position of
hyperextension. The persistent use of hyperextension
in these exercises can actually decrease knee stability
and irritate tissues rather than provide the desired
increase in joint stability and muscle strength.
(Text continues on p. 279.)development aesthetics. Such recruitment patterns
could theoretically be encouraged by cues that direct
students to use more of the inner thighs (hip adduc-
tors) and back of the leg (hamstrings). An example
in which cueing designed to emphasize greater use
of the hip muscles (e.g., reaching the knees as close
to directly side as possible on the down-phase and
then pulling the inner thighs up and together on
the up-phase of a plié) changed muscle recruitment
patterns such that greater activity in the adductor
and hamstrings occurred, as shown in figure 5.29C.
In contrast, cueing to promote the undesired tech-
nique of “letting the knees drop inward” resulted in
greater activation of the quadriceps in this skilled
dancer (figure 5.29B).
While excessive use of the quadriceps femoris
should be discouraged in order to meet aesthetics in
some dance forms, this does not mean that the quad-
riceps should not be used and that the quadriceps
should not be strong. As previously discussed, the
quadriceps are essential for controlling positioning
of the knee. The issue is one of relative contribution
of the quadriceps and magnitude of contraction, not
of avoiding its use.Conditioning Exercises for the Knee
Adequate strength and flexibility of the muscles
crossing the knee are important for performance of
demanding movements such as jumps, hinges, falls,
floor work, and grand pliés. A balance of strength
and flexibility is also important for preventing
injury.Selected Strength Exercises for the Knee
The most key muscle groups acting on the knee and
patellofemoral joints are the quadriceps femoris
(knee extensors) and hamstrings (knee flexors). For
joint stability and proper mechanics it is essential that
both of these muscle groups have both adequate
and balanced strength. With the common use of
the quadriceps as antigravity muscles, they can be
three times stronger than their antagonists, the
hamstrings (Hamill and Knutzen, 1995), and it is
important that dancers not neglect strengthening
the hamstrings. Sample exercises for these muscles
are provided in table 5.3, and a brief description of
their importance follows. Since the hamstrings and
one component of the quadriceps femoris (rectus
femoris) act on the hip as well as the knee, some
strengthening exercises for these muscles were
described in chapter 4. Exercises for other members