Analysis of Human Movement 499height (vertical component), distance (horizontal
component), or other criteria.
When providing cues or considering the addition
of supplemental conditioning exercises, it is very
important to keep the specificity of these goals in
mind. For example, several studies practicing jumps
in various environments showed no gains in jump
height or gains lower than reported for other athletes
in jump height (McLain, Carter, and Abel, 1997;
Poggini et al., 1997). Instead, it appears that dancers
may naturally tend to favor emphasizing improve-
ment in technique, efficiency of movement (Harley
et al., 2002), or constraining peak impact forces.
One would theorize that if increased jump height
was the goal, a program should be utilized that inte-
grates key lower extremity strengthening exercises
to allow greater absorption of forces as jump height
increased, as well as cues and functional movement
patterns emphasizing jump height. The specificity
of motor control strategies is demonstrated by stud-
ies showing a greater contribution of the hip with
greater jump height (Vanrenterghem et al., 2004),
adjustment of lower extremity tension (stiffness)
upon landing in accordance with jump height and
floor force absorption characteristics (Devita and
Skelly, 1992; Hamilton and Luttgens, 2002), and
significant improvement in dancers’ vertical jump
height off two feet and off the right foot (but not
the left) after a plyometric training program (Griner,
Boatwright, and Howell, 2003). This latter finding is
particularly interesting given the tendency for many
right-handed ballet dancers to prefer jumping off
their left legs (Golomer and Fery, 2001).
The process of improving jumps is also com-
plicated by aesthetic requirements. For example,
greater hip flexion obtained by more forward lean
of the torso will allow markedly greater force pro-
duction in the takeoff phase of jumping, probably
largely related to the ability of the gluteus maximus
to produce more force in this position. Similarly,
greater hip flexion obtained by more forward lean
of the torso will also allow for lower impact forces
upon landing (Devita and Skelly, 1992), probably
in part due to bringing the center of mass of the
torso closer to the knees (decreased moment arm of
resistance). However, dance generally encourages a
more vertical positioning of the torso, and aesthetics
will limit the amount of forward lean of the torso
that is permitted.
Optimal Performance Models.
So, anatomical and biomechanical analysis of move-
ment can provide vital information that can deepen
our understanding of a given movement. However,
whether this information can be used to develop an
optimal performance model is controversial and
complex. Such models will need to take into account
individual differences and the observation that with
complex movement, different movement strategies
can be developed to achieve the same movement
outcome. The strategy that works for one elite ath-
lete may not necessarily be optimal for another due
to many variables such as body type, lever length,
muscle fiber type, strength and power in key muscles,
flexibility in key joint ranges of motion, and other
neuromuscular factors. Still, when studies of multiple
elite strategies are combined with theoretical ana-
tomical and biomechanical analyses, a pattern usually
emerges that is consistent with scientific principles
of movement. From such models, recommendations
can be generated for instructing and improving skill
in a given movement task, taking into consideration
the differences between individuals.
In dance, this issue of generating models of
optimal performance is made more complex by the
tremendous variety of movements used. In contrast
to walking, running, hurdling, or high jumping,
where there is one movement pattern or sequence
to be studied, dance contains many basic movement
categories including walks, runs, leaps, slides, skips,
jumps, lunges, swings, pliés, rises, reaches, brushes,
kicks, drops, isolations, contractions, turns, and falls,
as well as countless variations and combinations of
these and other movement vocabulary.
Generating models of optimal performance in
dance is also made more difficult by the need to meet
aesthetic criteria. In many forms of athletics, the
primary goal is to accomplish a movement outcome
that can be measured quantitatively. For example, in
the high jump, the goal is to jump as high as possible
over a bar, and the success of the outcome is basi-
cally determined by how high a bar can be cleared.
In contrast, dance is heavily guided by meeting
aesthetic criteria not only in the outcome but also
throughout the process of achieving the outcome.
With regard to turns, for example, in many schools
of dance there may be a quantitative component in
that it is desirable, and considered a sign of greater
skill, to be able to perform multiple repetitions of
a given turn. However, the preparation for the turn
and the manner in which the turn is performed are
considered vitally important, not just the number
of revolutions accomplished. This emphasis has
led to the statement by some that when compared
to many forms of athletics, dance is process as well
as product oriented. Furthermore, while some of
these aesthetic criteria involved in the “process” of