The Knee and Patellofemoral Joints 273
the torso slightly forward in movements such as a
turned-out plié is often associated with more sense
of effort in the quadriceps than performing the same
movement with the torso more vertical. Alternatively,
degree of quadriceps activation may relate more to
habit and preferential muscle recruitment strategies.
The electromyography (EMG) tracings from the
dancers shown in figures 5.28 and 5.29 exhibit a wide
variety of recruitment patterns in terms of magnitude
of quadriceps contraction and of relative contribu-
tion of the hamstrings and hip adductors. Teaching
dancers to emphasize greater use of the hip exten-
sors and hip adductors may allow less contribution
of the knee extensors, which would be potentially
advantageous in terms of reducing patellofemoral
compression forces as well as meeting quadriceps
FIGURE 5.28 EMG recordings during a second-position plié
of (A) a highly skilled dancer with movement economy and (B)
a less-skilled dancer with excessive muscular effort. Key: 1 =
hip adductor (adductor longus), 2 = quadriceps femoris (vastus
medialis), 3 = hamstrings (biceps femoris).
1
3
2
1
3
2
FIGURE 5.29 Example of muscle activation patterns for a
skilled dancer performing a second-position grand plié with
(A) routine performance, (B) cueing to “let the knees drop
in,” and (C) cueing to “reach the knees side.” Key: 1 = hip
adductor (adductor longus), 2 = quadriceps femoris (vastus
medialis), 3 = hamstrings (biceps femoris).
1
3
2
1
3
2
1
3
2
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