194 Dance Anatomy and Kinesiology
Compressive Loads on the Hip Joint
The hip joint is required to bear body weight during
upright standing and the support phases of move-
ments such as walking and running. During standing
with the weight evenly distributed between the two
feet, each hip joint must support one-half of the
weight of the body segments above the hip, or about
one-third of total body weight (Hall, 1999). However,
during standing on one leg, that hip must now sup-
port the total weight of the head, arms, and trunk, as
well as the weight of the opposite leg, or about 85%
of total body weight (Smith, Weiss, and Lehmkuhl,
1996). In addition, the load actually borne by each
hip is significantly greater than just body weight
during movement due to the additional compression
produced by contraction of the strong muscles of the
hip and impact forces translated upward from the
foot. So, during walking and jogging, compressive
loads on the hip can range from three to five and a
half times body weight (Hall, 1999) and with activities
such as stair climbing may reach seven times body
weight (Levangie and Norkin, 2001). Hip loading
can also be markedly increased by the wearing of
hard-soled shoes, hard heel strikes during locomo-
tion, and carrying a load (as in partnering). The
high loads borne by the hip make it vulnerable to
degenerative changes that can lead to having total
hip replacements in dancers at younger ages than
one would expect or hope.Special Considerations for the Hip in Dance
Varied movements, often encompassing a large
range of motion at the hip joint, requiring complex
coordination between movements of the pelvis and
femur, and utilizing multiple planes, are essential for
meeting the aesthetics of dance. Examples of such
movements include the roll-down, flat back positions,
and many movements employing turnout such as
extensions and the arabesque.Roll-Down
When first learning a roll-down, some dancers make
the error of emphasizing flexion of the hip too early,
before adequate flexion of the spine has occurred.
This increases the torque from the weight of the torso
and often is accompanied by shifting the pelvis back
in an attempt to counterbalance this torque and pre-
vent the dancer from falling forward (figure 4.30A).
However, to achieve the desired dance aesthetic andlessen low back and knee stress, the dancer should
apply the lumbar-pelvic rhythm, first utilizing the
abdominal–hamstring force couple to maintain a
neutral pelvis while motion is isolated to spinal flex-
ion. During this motion the dancer should focus on
sequentially flexing the spine from the top down and
keeping the head as close to the torso and pelvis as
possible. When spinal flexion is complete, focusing
on rotating the pelvis about the femur, with the head
of the femur staying in place as much as possible and
the ischial tuberosities rapidly going up toward the
ceiling, will help achieve the aesthetic and desired
positioning of the pelvis closer to being over the
ankle joint (figure 4.30B).Flat Back Positions
Jazz and some modern classes also frequently use
flat back positions (figure 4.31A). In contrast to
roll-downs, these positions actually primarily involve
hip flexion (not spinal flexion) while contraction
of the spinal extensors is used to prevent undesired
flexion of the spine. Strong contraction of the ham-
string muscles is required (eccentrically) to control
the flexion of the hip, and when muscles are not
adequately warmed or when forceful bouncing is
added to these positions, hamstring strains can occur.
Furthermore, in this flat back position, the moment
arm is very large for the spine, and so large forces
are imposed on the spine. To reduce injury risk,
it is recommended that when these positions are
used, the hamstrings and spinal extensors be first
adequately warmed up, the use of large bounces
and momentum be avoided, and students be cued
to use firm abdominal co-contraction to help reduce
spinal stress and avoid lumbar hyperextension. For
dancers having difficulty effectively activating this
latter abdominal co-contraction, it may be helpful
to practice from a kneeling position with the chest
supported on a ball (to reduce the moment of the
resistance). First, carefully allow the abdominals to
relax and the low back to arch (figure 4.31B). Then
contract the abdominals to achieve the desired flat
back position (figure 4.31C). As skill develops, this
position can then be tried standing without the
ball, requiring well-coordinated co-contraction of
the abdominals, back extensors, and hip extensors.
If needed, the fingertips can be placed on a wall or
barre to reduce the resistance from the weight of
the torso.
Some dance sequences combine flat back posi-
tions with roll-downs. These combinations can be
helpful for developing spinal articulation; coordi-
nated movements between the spine, pelvis, and