Learning About the Hip

            “To keep the body in good health is a duty...”~Buddha

         The hip joints are responsible for bearing the weight of our bodies.  When a person is standing, the weight of the upper body is divided in half where the spine meets the pelvis and distributed evenly between the two hip joints.  Since each of these joints must bear one half of the body weight, we would expect them to be extremely stable, strong joints.  Surprisingly, the hip joint is one of the most flexible joints in the body, second only in flexibility to the shoulder joint.

            This joint is a ball and socket joint formed where the ball-shaped head of the thigh bone, or femur, fits into an indentation, or shallow socket, in the pelvis called the acetabulum.  This type of joint allows for movement in almost any direction.  The hip is capable of flexing, extending, abducting (moving away from the center of the body), adducting (moving toward the center of the body), or a combination of all these movements called circumduction, which allows for hip rotation.

            The joint is lined with a pearly blue hyaline cartilage.  This type of cartilage is strong but flexible and elastic and is found in most of the body’s joints.  It allows for a free gliding motion between the femur and the acetabulum and also acts as a shock absorber, during activities like jumping, running, or walking.

            The joint is also lined with synovial membranes.  These membranes secrete synovial fluid, which lubricates the body’s joints, reducing friction and keeping the bones sliding freely against each other.

From teachmeanatomy.info

            The femur is held in place by a capsule made up of the iliofemoral ligament, the pubofemoral ligament, and the ischiofemoral ligament.  The iliofemoral ligament, which is also called the Y-ligament because of its shape, runs from the outer rim of the acetabulum to the base of the femoral neck and to the lesser trochanter (the small protrusion on the inside of the femur).  The pubofemoral ligament runs across the front of the joint, and the ischiofemoral ligament runs across the back of the joint, and these both help prevent hyperextension of the hip joint.  The ligamentum teres is a ligament that attaches the femur to the acetabulum.

            The hip joint is surrounded by a multitude of muscles that provide strength and stability to this flexible joint.  Each of these muscles perform at least two actions.  Generally, the muscles that run along the front of the thigh, often referred to as the quadriceps, are responsible for flexing the hip, and the muscles that run along the back of the thigh, often called the hamstrings, are responsible for extending the hip

, and most of the muscles responsible for outwardly rotating the leg begin at the back of the hip joint and run down the outside of the leg.

            My next blog post will focus on conditions and injuries of the hip that are common in dance.

How to Increase Turnout Safely

            "Turn-out is something a dancer does, not necessarily something he has." - Anne Woolliams

            Since turnout is an integral part of ballet technique, it is important for dancers to learn how to turn out and maintain it in ways that are healthy for their bodies. 

            The hip is the only ball and socket joint in the leg.  This type of joint allows for movement in all directions and provides the ability to rotate the leg outwardly, or turn out.  The amount of turnout a dancer has is largely pre-determined by the angle and length of the femoral neck, the facing of the hip sockets and the flexibility of the muscles of the hip.

            The hip joint is formed where the head of the femur, or thighbone, fits into the socket, or acetabulum of the pelvis.  The neck of the femur forms an angle, between the femoral head and the long shaft of the femur that allows the femur and pelvis to connect.  This average angle measurement is about 15°.  When the angle is less than 15°, the legs will naturally rotate outward, but if it measures more than 15°, the legs will naturally rotate inward. (2)

            Outward rotation also occurs naturally if the hip sockets, or acetabula, face sideways rather than diagonally forward.

            Those with a longer femoral neck enjoy a greater range of motion at the hip joint.  However, a shorter femoral neck limits the range of motion because the femur comes in contact with the outer rim of the pelvis.

            The muscles surrounding the hip include those that flex the thigh, extend the thigh, inwardly rotate, outwardly rotate, adduct (pull the leg toward the midline of the body) and abduct (pull the leg away from the midline of the body).

            Unlike the previously mentioned bony structures, muscles can be changed through exercise.  Ballet dancers often ask which muscles they should strengthen and/or stretch to improve their turnout.  The answer is a simple one – all of them.  All of the muscles surrounding the hip perform more than one function.  There is no muscle that acts only as an outward rotator.  Moreover, it is important to remember that ballet dancers perform exercises that always require an additional action to turning out.  A grand battement to the front requires flexion, a grand battement to the back requires extension, beats require adduction and dégagés require abduction.  When these exercises are being performed, the muscles of the opposite hip must also work as stabilizers to keep the dancer’s standing leg steady, turned-out and lifted.

            By strengthening and stretching all of the hip muscles in a conditioning program, the dancer will increase the range of motion at the hip joint.  This greater range of motion will allow for increased turnout, and the strength training will provide the dancer with the ability to maintain that rotation during exercises.

quadriceps stretch

seated frog press           

In Dance Kinesiology, Sally Sevey Fitt provides a hip conditioning program which includes single leg lifts to 45 degrees  while lying on the back and the stomach, stretching the hamstrings while lying on the back and holding the legs in second, stretching the quadriceps, the seated frog press, the yoga sit stretch and the lying knee press. The lying knee press involves lying on the back with the feet hip distance apart. The knees are allowed to fall in and are then actively pressed together for 20 seconds. This action is followed by allowing the lower body to twist to the right while the left leg is rotated inward to stretch the outward rotators and is then repeated for the right leg. (1)

yoga sit stretch

            A word of caution….A stretch that dancers often use to increase turnout is known as the frog and is done while lying on the stomach.  This stretch needs to be AVOIDED!  The position of the legs places unnecessary stress on the ligaments of the knee and can do more harm than good.

AVOID THE FROG!!!

            By using a supplemental conditioning program to strengthen and stretch the muscles surrounding the hip, dancers will establish a greater range of motion and develop the strength necessary to hold positions.  Exercises done in class specifically target the outward rotators while supplemental exercises will keep the hip healthy and prevent dangerous muscular imbalances from occurring and causing injuries.

(1) Fitt, Sally Sevey. Dance Kinesiology. New York, NY:Schirmer Books; 1988.

(2)Wilmerding, Virginia & Krasnow, Donna. Turnout for Dancers:  Hip Anatomy and Factors Affecting Turnout. International Association of Dance Medicine and Science; 2011.  Retrieved from http://www.iadms.org/displaycommon.cfm?an=1&subarticlenbr=325.