The Pelvic Girdle and Hip Joint 189an extended hip on the support leg in many dance
movements. Bridging (table 4.5F, p. 215) is a con-
ditioning exercise that is aimed at simulating these
latter functions of the hip extensors. These closed
kinematic chain uses of hip extension are very impor-
tant in activities of daily living and in dance.
As with other joint movements, when hip exten-
sion occurs in the same direction as gravity, the oppo-
site muscle group is generally key in controlling the
movement. For example, when the leg is lowered in a
controlled manner from being lifted to the front, this
type of hip extension involves eccentric contraction
of the hip flexors versus the hip extensors.Hip Abduction
Hip abduction is movement in a sideways direction,
such that the angle between the lateral surfaces of
the articulating bones decreases. The gluteus medius
and minimus are assisted by other hip abductors
listed in table 4.4 to perform their customary open
kinematic chain action when contracting concentri-cally against gravity or resis-
tance to move the femur
sideways in the side leg
raise (table 4.5, G and H,
pp. 216-217), a side kick
in karate, jumping jacks,
or side lunges. Examples
from dance include parallel
movements to the side such
as a lateral tilt, extension,
tendu, dégagé, or attitude
as shown in figure 4.26.
When one foot remains
fixed and in contact with
the ground (closed kine-
matic chain movements),
concentric hip abduction
plays a key role in pull-
ing the side rim of the
pelvis closer to the greater
trochanter on the weight-
bearing side, countering
the undesired tendency
caused by gravity for the
pelvis to drop (laterally tilt)
to the opposite side. This
function of the hip abduc-
tors, called the abductor
mechanism (Soderberg,
1986), is important in walk-
ing and dancing to allow
maintenance of balance
and appropriate positioning of the body over the
support foot while on one leg. Performing a standing
side leg raise (table 4.5H, p. 217) while attempting to
maintain a level pelvis with the body weight appropri-
ately positioned over the support foot can be used to
develop this important postural function of the hip
abductors.
When an individual has dysfunction of the hip
abductors, such as gluteus medius weakness, a
distinct drop of the pelvis will be seen to the oppo-
site side that the person is unable to correct. This
undesired drop of the pelvis is called a positive
Trendelenburg sign.Hip Adduction
Hip adduction is a sideward movement in a medial
direction toward the median plane such that the
angle between the medial surfaces of the articulat-
ing bones decreases. The adductor longus, adductor
brevis, adductor magnus, and gracilis are assisted by
the pectineus (table 4.4) to perform their customaryFIGURE 4.25 Sample dance movement showing hip extension.
© Angela Sterling Photography. Pacific Northwest Ballet dancers Louise Nadeau and Christophe Maraval.