Analysis of Human Movement 497“Don’t Stop Your Plié”
W
hen dancers are performing a preparatory plié prior to a demanding movement such as a jump
or turn, the cue to “not stop your plié” is sometimes given. Often a further explanation of this
cue is to “avoid hesitating or stopping” at the bottom of the plié. From a mechanical perspective,
hesitating or delaying at the bottom of the plié will lessen the benefits of the stretch-shortening cycle.
The potential enhancement from the prestretch of key muscles such as the calf muscles, quadriceps
femoris, hamstrings, and gluteus maximus rapidly declines if there is much delay between the eccen-
tric and the following concentric contraction. So dancers should be encouraged to make a very rapid
reversal from the down- to the up-phase of the movement. The commonly used counting technique
of “and one,” with the “and” rapid and the “one” emphasized, versus an even count of “one” for the
down-phase of the plié and “two” for the up movement, can also be helpful in encouraging the desired
quick reversal of direction without a hesitation.DANCE CUES 8.2
“Land Softly”
T
he instruction to “land softly” is often used by teachers in an effort to reduce the forces associ-
ated with landing. From a biomechanical perspective, soft versus stiff landings are associated with
lower vertical ground reaction forces; greater absorption of forces by the hip and knee muscles; slightly
less absorption of forces by the ankle plantar flexors; and greater hip flexion, greater knee flexion,
and slightly less plantar flexion at the beginning of floor contact (Devita and Skelly, 1992; Kovacs et
al., 1999; Self and Paine, 2001). In soft versus stiff landings from a vertical fall of 23 inches (59 centi-
meters), Devita and Skelly found that overall the muscular system absorbed 19% more of the body’s
kinetic energy, thereby reducing impact stress to other tissues. While just using the cue of landing
“softly” may be sufficient to elicit the desired response from a dancer, some dancers are unclear as to
how to achieve this type of landing. For example, one study found that providing video feedback with
specific verbal analysis of how to land more softly was more effective in reducing peak vertical forces
both directly following instructions and one week later than simply instructing subjects to key into the
sensation of landing and try to land more softly (Onate, Guskiewicz, and Sullivan, 2001). Similarly,
using more abstract images has been found to be less effective than providing more concrete direc-
tives related to changes in joint angles or the sound of landing (McNair, Prapavessis, and Callender,
2000). One approach is to emphasize some of the biomechanical criteria associated with soft versus
stiff landings. Practically, these can be encouraged by directing dancers to think of slightly flexing the
knees and hips just before landing and then using a slightly deeper but slower plié to decelerate the
body. This directive can also be valuable for preventing knee hyperextension when landing, the classic
mechanism for anterior cruciate ligament tears in dancers.DANCE CUES 8.3
ground reaction forces that stay elevated for a shorter
period of time (Dufek and Bates, 1990).
Also in line with these principles, a study of travel-
ing dance jumps showed that the quadriceps femoris
was particularly important in attenuating impact
forces as jump distance and vertical ground reaction
forces increased (Simpson and Kanter, 1997). Two
additional studies showed that trained dancers had
significantly greater degrees of knee flexion and hip
flexion (deeper pliés) when landing from vertical
jumps than non-dancers (Clarkson, Kennedy, and
Flanagan, 1984; McNitt-Gray, Koff, and Hall, 1992),