Pelvis and hips - Lecture notes 1 PDF

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Lecture notes on the anatomy of the pelvis and hips...

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Pelvis and Hips (tech & anatomy)

All dancers need to understand how the forces of leg movement are distributed through the hip joints and pelvis. This will enhance technique as knowledge of coordination of body parts and pelvis control grows. All musculature inserts into the pelvic region and leg muscles begin at pelvis, so the pelvis provides a link between the trunk and the legs. It is powerful when organized and balanced as it is the base of your centre so is where movement originates. The Pelvis is made up of the ilium, ischium, and pubic bones (on either side). The sacrum connects the spine to the pelvis. Your centre of gravity lies just in front of the sacrum. In order to maintain your centre of gravity when standing on one leg you must visualize a vertical line from the pelvis and sacrum to the floor. Alongside the pelvis is the acetabulum (deep hip socket) which is where the femur (thigh bone) inserts. The femur is the strongest and longest bone in the body. The acetabulum allows the femur to lift forward or extend back and allows the thigh to perform battement to the side and turn in or out. The head of the femur angles downwards, creating two bony prominences: the lesser trochanter (located medially) and the greater trochanter (located laterally) which both contain muscles which help to create pelvic stability for the standing leg and dance movement for the gesture leg. Hip Disassociation- isolating movement at the hip, separate from the pelvis or spine. Concentric Contraction- shortening the muscle with contraction. Eccentric Contraction- lengthening the muscle fibers (but maintaining strength &muscle tone). Relaxing and lengthening the muscles allows for greater fluidity and range of motion. Battement......anterior muscles contract and posterior muscles release and lengthen eccentrically.

PELVIC LINK The iliopsoas muscle connects the lower spine and pelvis to the femur at the lower trochanter. Weakness and tightness here can result in misalignments of the lower back and pelvis which then effects the alignment of the legs. Eg. The iliopsoas crosses over the hip joint and can cause snapping as the leg comes down from developpe which can produce pain and develop into an injury that requires physician assessment. Maintaining strength and flexibility in the iliopsoas will prevent snapping. ILIOPSOAS IS THE MAJOR HIP FLEXOR- flexes hip to allow movement above a 90` angle It originates on the anterior aspect of the lower spine vertebrae. Tightness here pulls the lower spine into extension, tilting the front of the pelvis forward and preventing the ability to hold the pelvis in a neutral position (anterior pelvic tilt). When combined with a lower-back arch, an inability develops in

the abdominals an adductors (inner thigh muscles) and a tightness occurs in the lower-back musculature, creating a shearing force against the vertebrae.

LATERAL HIP POWER The Gluteus Minimus and Gluteus Medius connect the outer surface of the ilium with the lateral area of the greater trochanter and help with abduction and hip stabilization. Weakness here is associated with ankle injuries. The Tensor Fasciae Latae connects the outer ilium with the Iliotibial Band (band of fascia running from the ilium down the side of the thigh to the lateral femur, patella, and tibia).

CONTROL OF THE PELVIC FLOOR MUSCLES Pelvic Floor Muscles: • • • • • •

Form the bottom of the core- critical in supporting the pelvis Series of muscles lining the base of the pelvis Muscles connect to pelvic diamond and form a ‘basin’ In a basic modern contraction, sit bones of diamond move together slightly as pelvic floor muscles contract If lower back is arched and pelvis tilted forward, sit bones move apart- eccentrically lengthening the muscles On a downward phrase, the pelvis stays neutral and the diamond widens. On an upward phrase the pelvis stays neutral and the diamond shrinks

ROTATION OF THE FEMUR An excellent balance of strength and flexibility between the internal and external rotators must exist to allow the femur to turn in and out as required for the dance style being demonstrated. Six small muscles located deep under the gluteus maximus play a large role in turnout and stabilization of the hip joint- ex, the piriformis muscle connects to the sacrum and posterior ilium with the greater trochanter, the obturator internus and obturator externus connect the ischium and pubic bone with the greater trochanter, the quadratus femoris connects the sit bones with the greater trochanter (these muscles are referred to as the deep six). INTERNAL ROTATION of the femur is shared by multiple muscles: Semitendinosus and Semimembranosus (two of the hamstring muscles) Gluteus medius and Gluteus minimus (via anterior fibers) Tensor Fasciae Latae Better hip disassociation skills allow for more effective hip movement and core stability.

TURNOUT Factors effecting turnout include strength of the external rotators, flexibility of the internal rotators, and bony alignment of the femoral head and neck but the majority of turnout must come from movement in the hip socket. 60% comes from hip, 20-30% from ankle, 10-20% from knee and tibia. By contracting the deep external hip rotators, you can achieve a full turn out within the hip socket. When executing a plie, allow the rotators to contract to keep the femurs open along the frontal plane and aligned over the toes. On the downward phrase, the inner-thigh muscles assist by working eccentrically, on the upward phrase, they work concentrically. Small external rotators: As the muscle fibers contract and shorten, the femur rotates laterally in the socket. It can turn out in the hip socket without unwanted movement in the lower back or pelvis (supporting the disassociation theory). With focus, you can move your thigh without moving your pelvis or spine. To attain ideal turnout, you must work within your means and with proper skeletal alignment. Ideal turnout is 180’ but this is physically demanding and can create compensation and potential injuries for some dancers. Focusing on turning out from your hips can minimize the stresses on the knee and ankle. For better turnout: • • •

Always align your patella (kneecap) over your second toe, to avoid screwing or twisting through the knee joint Keep your weight placed equally over your head and first and fifth metatarsals to avoid the overpronating (flatfooted/rolling feet inwards) of the feet Maintain pelvis in a firm, neutral position, utilizing the abdominals and deep hip external rotators avoiding the anterior pelvic tilt

BONE ALIGNMENT Femoral Anteversion: forward placement in hip socket causing abnormal internal rotation of the femur, making it anatomically difficult to execute turnout. Causes an anterior tilt of the pelvis. Forced turnout will cause screwing of the knees and rolling in at the foot and ankle. Femoral Retroversion: Opposite of Anteversion. The angle of the femur allows for more external rotationturnout.

DANCE-FOCUSED EXERCISE •

Plie Heel Squeeze

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Weighted Coupe Turn-In Side-lying Passe Press Standing Inner-thigh Press Arabesque Prep Hip Flexor Lift Attitude lift Hip Flexor Stretch Passe...