Contact Us   |   Sign In   |   Register
General
Blog Home All Blogs

Introducing the knee: Anatomy and biomechanics

Posted By Elsa Urmston and Jonathan George on behalf of the IADMS Education Committee, Monday, November 28, 2016

As dancers, educators and clinicians, we know that knees cope with a lot!  Over the last decade or so, the demands placed on the dancer’s body has increased exponentially and ever more complexly.  Acrobatic movement is becoming evident and the effect to the joints of the limbs can often mean greater incidence of injury.  As Liane Simmel points out “pirouettes on the knees, knee drops, and even a plié in fourth position require particular leg stability and optimal mobility in the knee.”1  In reviewing the literature, Russell2 identifies the lower extremity to repeatedly be the most commonly injured region of the body amongst dancers.

 

 

The knee joint is hugely complex and as Teitz (in Solomon et al, 2005)3 explain there is no bony stability in its structure.  A modified hinge joint, the knee comprises articulations between the femur and tibia, and the patella and femur, held together by a fibrous capsule and connected via a network of ligaments.  It’s this lack of potential stability which makes the knee prone to injury, often through misalignment and poor mechanics, although as well through sudden trauma or overuse.  Over the next couple of weeks we have a series of posts which focus on the knee; today we zone in on the structure, anatomy and mechanics of the knee itself.  Part 2 provides an overview of common knee injuries amongst dancing populations, and in Part 3 we focus on two case studies of young men who have experienced knee issues during their training and have been successfully rehabilitated to class and performance via a joined-up clinical and educative rehab programme.

 

 

The tibio-femoral joint is a hinge joint, capable of flexion (bending) and extension (straightening).  The screw-home mechanism allows the knee to slightly internally and externally rotate too.  During the last 30° of knee extension, the tibia (open-chain movement such as rond de jambe en l’air) or femur (closed-chain movements such as ascending from a demi-plié) must externally or internally rotate respectively by about 10°.  This determines the knee as a modified hinge joint.  You can see Rosalie O’Connor from American Ballet Theater demonstrating the screw-home mechanism in a rond de jambe action here!

 

The patellar-femoral joint serves to heighten stability in the joint.  The patella (knee cap) is a sesamoid bone which sits in the quadriceps muscle, and during flexion and extension undergoes complex gliding movements. The fairly unanimous consensus as to the function of the patella is to effectively increase the movement arm of the patella tendon about the tibio-femoral joint, thereby magnifying the movement and force of the quadriceps muscle group about the knee.4

 

 

The stability offered by the joint capsule is complemented by numerous, strong ligaments and more than any other joint in the body, these ligaments are vital in guiding the aligned movements of the bones as they come together to form the joint.  Yet, they are arranged in such a way that the stability is not always constant; some remain taut to ensure stability when the knee is extended and others slacken to ensure mobility when the knee is flexed5.

 

The medial and lateral collateral ligaments

The collateral ligaments are located on either side of the knee joint (collateral means side by side).  The medial collateral ligament – the one on the inside of the knee – is taut in knee extension and external rotation.  It controls the knee if the knee rotates inwards and in fact when the knee bends in a demi-plie, it controls approximately 80% of the medial stress on the knee (Besier et al, 2001)6.  The lateral collateral ligament – located on the outside of the knee – becomes taut with knee extension and provides lateral stability to the knee.  It controls approximately 70% of the lateral stress of the knee for example when the knees bow out on flexion and cause the feet to roll outwards (Besier et al).

 

The cruciate ligaments

The cruciate ligaments join the tibia and femur to one another within the internal structure of the knee.  The cruciate ligaments prevent any forward/ backward motion of the femur and tibia in relation to one another.  The anterior cruciate ligament also has another role in aiding rotation of the knee and controlling hyperextension in the joint.  It also plays a role when deceleration from jumping, floor work and quick changes of direction are required. It is now also widely accepted that the anterior cruciate ligament provides up to 40% of medial knee stability7.

 

The menisci

The medial and lateral meniscus are two cartilaginous discs which sit on the tibia and deepen the articular surface of the knee joint – they provide a kind of collar in which the bony ends of the femur sit, thereby improving the congruency and stability of the knee joint.  They assist with shock absorption and help to friction thus aiding smooth knee movement. The menisci are critical in the production of synovial fluid-‘the oil’- around the knee joint.

 

Bursae

The knee has the most extensive distribution of bursae in the body. More than 20 bursae are thought to be within the knee joint, with the primary role of reducing friction amongst the structures of the knee joint.  Many are located around the patella to aid its gliding function within the muscle and over the top of the joint itself.

 

Iliotibial Band

The iliotibial band is an adaptation of erect posture and provides key lateral support to the knee and hip; it runs down the side of the upper leg from the rim of the pelvis, to the outer edge of the femur and tibia.

 

This super video really provides a great introduction to the anatomy and ligament structure of the knee joint – take a look!

 

 

The musculature

As with the skeletal anatomy of the knee, the muscles which act on the knee are complex!  Because the muscles of the thigh also act on the hips, they often have a dual purpose –hip movement is included in brackets for ease of understanding here!  We have provided a simple table of the main muscles which act on the knee to produce movement.

 

Muscle

Action

Anterior/ front of the thigh

Rectus femoris

Knee extension (hip flexion)

Vastus medialis

Knee extension

Vastus intermedius

Knee extension

Vastus lateralis

Knee extension

Sartorius

Knee flexion (hip flexion, hip abduction and hip external rotation)

Posterior/ back of the thigh

Biceps femoris

Knee flexion and external rotation (hip extension and hip external rotation)

Semitendinosus

Knee flexion and internal rotation (hip extension and hip internal rotation)

Semimembranosus

Knee flexion and internal rotation (hip extension and hip internal rotation)

Popliteus

External rotation of femur when foot fixed; internal rotation of tibia when foot free

Medial surface of thigh

Gracilis

Knee flexion (hip adduction and hip flexion)

Posterior/ back of calf

Gastrocnemius

Knee flexion (ankle plantarflexion (pointing))

 

 

As you can see muscles often have more than one role in creating the movement of the limbs – we separate them out to learn about them, but of course they should be seen in their entirety to understand the complexity of the muscular system.  This video really helps us to see the wholeness of this system but understand each individual muscle’s location in relation to each other – take a look.

 

 

 

 

1.    Simmel, L.Alignment of the leg and its impact on the dancer's knee: Clips from the 2014 Annual Meeting
2.    Russell, J. Preventing dance injuries: Current perspectives, Journal of Sports Medicine, 4, 199-210.
3.    Solomon, R., Solomon, J. & Cerny Minton, S. Preventing Dance Injuries.  Champaign, IL: Human Kinetics, 2005.

4.      DeFrate LE, Nha KW, Papannagari R, Moses JM, Gill TJ, et al. The biomechanical function of the patellar tendon during in-vivo weight-bearing flexion. Journal of Biomechanics 40:1716–1722, 2007.

5.      Clippinger, K. Dance anatomy and kinesiology.  Champaign, IL: Human Kinetics, 2016.

6.      Besier, TF., Lloyd, DG.,  Cochrane, JL. and Ackland. TR. External loading of the knee joint during running and cutting maneuvers. Medicine and science in sports and exercise33, no. 7:1168-1175, 2001.

7.      Quatman CE, Kiapour AM, Demetropoulos CK, et al. Preferential loading of the ACL compared with the MCL during landing: a novel in sim approach yields the multiplanar mechanism of dynamic valgus during ACL injuries. American Journal of Sports Medicine, 42:177–186, 2014.

 

More information about the knee’s structure can be found in a variety of dance specific dance anatomy, kinesiology and safe practice books.

 

Elsa Urmston is the Centre for Advanced Training Manager at DanceEast, Ipswich, UK as well as Chair of the IADMS Education Committee and a member of the One Dance UK Expert Panel for Children and Young People.  Jonathan George is a Chartered Physiotherapist at the DanceEast Centre for Advanced Training.

Tags:  anatomy  biomechanics  dancers  knee  teachers 

PermalinkComments (1)
 

Feet: Skeletal and Muscular Structure

Posted By Elsa Urmston on behalf of the IADMS Education Committee, Tuesday, April 5, 2016

Over the next few months the Education Committee bloggers shine a light on the importance of the feet.  In June, Maggie Lorraine will write a two-part blog which focuses on potential foot injuries, structural issues, and working with them in dance.  We look forward to her insight.  By means of introduction to this topic, this short blog provides an introduction to the foot’s skeletal and muscular structure.



We all know that tired feeling in our feet at the end of a busy dancing day, don’t we?  They ache, they click, and let’s face it, dancers’ feet aren’t always the prettiest of things!  We look down at our bruised feet and hard skin, massage our insteps, and slather on moisturizer in an attempt to keep them as pliable as possible.  And no wonder, they work hard and we ask a lot of them!!

 

But what do you know about the structure of the foot?  It’s a hugely complex skeletal structure, comprising 26 bones, 34 joints and more than 100 muscles1, tendons and ligaments, all arranged to be weight-bearing in all sorts of different contexts from pointe to heeled shoes, from sliding across the floor in bare feet to taking off and landing on all surfaces of the foot.  And of course, the foot contributes to that sought-after, beautiful line from the toes and arch of the foot and into the rest of the lower leg in an arabesque.  Most importantly the foot is designed to create resilience and acts as a shock-absorber to the rest of the body. As Russell2 explains, “the foot’s structure, with its many bones intricately fitting together, provides a dynamic platform on which to support the body. The foot’s adaptability to the floor or ground, regardless of whether or not it is encased in a shoe, is what starts the process of pushing off the floor, absorbing shock when landing from a jump, changing direction in turns, and providing a surface on which to spin, to name a few of the foot’s functions important to dance.”

 

There are many super resources online which can help you learn the various bones and joints of the foot for example here and here, plus this interactive tutorial: Foot Anatomy Tutorial.

 

We provide a simple diagram here.



The foot can be divided into the posterior and anterior sections.  The ankle joint itself (a synovial hinge joint) is formed between the distal ends of the tibia and fibula and the talus where plantarflexion (pointing) and dorsiflexion (flexed foot) occurs.  The seven tarsal bones including the talus then make up the posterior portion of the foot, nearest to the heel, or calcaneus.  Each tarsal bone is roughly square in shape with flat articular surfaces and together the surfaces glide past each other to provide lateral stability just below the ankle joint itself; they contribute hugely to subtle changes in balance and it is here that inversion (sickling) and eversion (winging) can occur.  The five metatarsals and fourteen phalanges comprise the anterior section of the foot, extending away from the ankle joint itself down towards the toes.  These bones act as levers, alongside the muscular system of the lower legs and feet to allow the dancer to come up onto demi-pointe and ultimately to jump and locomote.

 

The skeletal structure of the foot also creates the longitudinal and transverse arches of the foot which are vital to spread the dancer’s weight across the whole foot.  The arches absorb shock from the ground in landing from a jump which is why it is so important for dancers to maintain strong, articulate feet.  The arches are reinforced by the ligament system and power is achieved by the muscles working on the joints to create motion through the foot’s resilient dome-like structure.

 

As you’d expect, the muscular system of the foot is also complex! They can be divided into two groups; extrinsic and intrinsic muscles.  The extrinsic muscles arise from the anterior, posterior and lateral areas of the lower leg and are mainly responsible for actions such as plantarflexion, dorsiflexion, inversion, and eversion.  The intrinsic muscles are responsible for more fine motor control actions such as the adaptation of the foot to the body’s weight and balance and the movement of individual toes.  These intrinsic muscles are layered through the foot to achieve the precision and intricate demands that dancers place on their feet – no wonder our feet and ankles fatigue!  These two great tutorials are a great interactive introduction to the musculature of the feet.

 

Intrinsic Muscles of the Foot: Dorsal Muscles

 

Intrinsic Muscles of Foot:  Plantar Muscles

 

 

So, the balance between strength and flexibility is of paramount importance in the dancer’s foot.  When it is achieved we are able to power through space, travelling with height, speed, and dexterity.  The simple directive of ‘using the floor’ is familiar to many of us.  Building strength and articulation can be achieved through emphasising the stroking of the sole of the foot on the floor in tendu and degagé, leaving the heel until last as the foot extends away from the body, and lowering it first as the foot closes back in.  This pressing of the foot into the ground strengthens the intrinsic muscles of the foot whilst also rehearsing the action of pushing into the ground to propel the body in a specific direction - fabulous conditioning exercise and a cornerstone of many dance techniques.  For more inspiration see The Royal Ballet’s class broadcast in 2014, a series of tendu exercises feature from about 6 minutes from the start of the video.

 

But what if strength and flexibility of the foot structure is compromised either through poor posture or dynamics in alignment of the body, or indeed due to an acute injury sustained whilst dancing? Our forthcoming posts will tackle these issues in June 2016.

 

 

References

 

1.  Clippinger, K.  The ankle and foot, Dance anatomy and kinesiology. Human Kinetics, 2007, 297-371.

 

2.  Russell, J.  Insights into the Position of the Ankle and Foot in Female Ballet Dancers En Pointe.  The IADMS Bulletin for Dancers and Teachers, 6(1), 2015, 10-12.  Available here.

 

 

Elsa Urmston, MSc, PGCAP, AFHEA, is the DanceEast Centre for Advanced Training Manager, Ipswich, UK and a member of the IADMS Education Committee.  She also sits on the One Dance UK Expert Panel for Children and Young People.
Email: elsa.urmston@danceeast.co.uk

 

Tags:  anatomy  feet  foot 

PermalinkComments (0)
 

Alignment of the leg and its impact on the dancer's knee: Clips from the 2014 Annual Meeting

Posted By Liane Simmel, Tuesday, June 9, 2015

IADMS Simmel from Steven Karageanes on Vimeo.

This presentation gives an insight into the functional anatomy of the dancer’s knee, its biomechanical prerequisites and its economic use as base for a high resilience to dance injuries.

 

Over the last decade as more and more acrobatic movements invaded the various dance styles, the strain on the dancer’s knees has largely increased. Training on hard, inappropriate floors or dancing choreographies in high heels can add even more problems. Pirouettes on the knees, knee drops, and even a plié in fourth position require particular leg stability and optimal mobility in the knee. But dancers often pay little attention to their knees. They are seldom specifically warmed up, directly trained or used consciously in everyday life. Nonetheless, their functionality is a top priority if dancers’ knees are to be kept fit and healthy.

Being the largest joint of the body, the knee works as an important coordination centre to the leg. Located between the hip joint above and the foot below, it reacts to all movements and positions of these, its two functional partners. With its high number of daily repetitions, even seemingly small dance technical pitfalls like rolling onto the inner side of the foot in the turned out position or losing the alignment of the leg in demi plié  can lead to overuse problems and even acute injuries in the knee area.

As dancers are accustomed to work precisely on their coordination and alignment they do have a big supply of tools for improving leg alignment, be it in the dance class or in everyday life. They just have to be made aware of this potential...

When analyzing leg alignment and knee load in a dancer, there is more to consider than just screening the bony and functional anatomy of the lower extremity itself. When it comes to assessing the stress and load on the dancer’s knee, the form and mobility of the foot, the bony and muscular situation of the hip joint, the position and mobility of the pelvis as well as the torsion of the tibia play an important role. Thus, to get an impression about the dancer’s anatomical prerequisites, screening should start by analysing the anatomy of the whole functional chain: the foot, the torsion of the tibia, the antetorsion angle in the hip joint and the position and mobility of the pelvic girdle. To detect the keystones by which the dancer can influence, change and improve his or her individual biomechanics the next step in line is to assess the flexibility, function and muscular strength of all functional partners – foot, hip joint, pelvis and last but not least the knee itself.  

Being the most common challenges in many of the different dance styles, turnout, plié and hyperextended legs have been chosen to explain the approach of biomechanical awareness training in dance. Dancers spend a great deal of their days in the studio, but there is still a life outside the ballet room, and movements and biomechanics outside the studio seem to have potential for improvement in many dancers. Therefore the habits in the dancer’s everyday life movement should thoroughly be analysed and searched for negative influence on body functionality by imprinting unhealthy movement patterns in the dancer’s neurological motor program. If not detected and changed these often unconscious habits will be trained on a regular daily basis, imprinting into the dancers motion cortex. To break them up, specific exercises should be performed, with the focus on (1) mobilization (to allow new movement possibilities), (2) awareness (to make unhealthy movement patterns conscious and consider possible changes), (3) strengthening (to enable the muscles and the neurological system to perform unfamiliar movements) and (4) relaxation (to reduce unnecessary muscles tension and soft tissue restrictions). With “one second exercises” performed numerous times per day, the reset of the neurological motor program gets started.

Finally, what seems for the majority of the dancers the most challenging step, the new movement potential have to be transferred back from everyday life to the studio, to the individual dance technique. Easily understandable anatomical and biomechanical images and movement cues can support this tricky step. And last but not least: patience.

Liane Simmel, MD, DO, tamed, Tanzmedizin Deutschland e.V., Fit for Dance, Munich, Germany

Tags:  alignment  anatomy  presentation 

PermalinkComments (0)
 

Dancing with the pelvis: Alignment, deviations, and mobility

Posted By Clara Fischer Gam and Elsa Urmston on behalf of the IADMS Education Committee, Thursday, April 30, 2015

In the latest post from the IADMS Education Committee we started a two-post discussion on pelvic structure and alignment. We looked at pelvic anatomy, motion and came up with ideas for putting these concepts into practice in class. This second post will focus on pelvic alignment and its relevance to movement execution in the studio.


Source: Getty Images

We have all learned from experience: proper alignment is one of the basic building blocks for achieving the aesthetic line and form required for dance technique. We know that many are the contributors for good skeletal alignment, but one area that plays a special role is the pelvis.

Practitioners and researchers comment on the importance of pelvic alignment. As mentioned in the previous post, when in a natural position in relation to the rest of the body, the pelvis assumes neutral alignment because the surrounding joints and muscles are balanced. Neutral pelvic alignment can help us to achieve efficient execution of dynamic movements and static positions and therefore more effective muscle recruitment. Not only might neutral pelvis facilitate body movements in general but it also seems to improve specific action at hip and lumbar spine.

How to find your neutral pelvis?

As well as the image below, have a look at this handy youtube film which helps you find neutral pelvis.  Place the tip of your index fingers on the symphysis pubis, resting each of your wrists on the tips of your front hip bones (right on those bony projections, called anterior superior iliac spines) and let your thumbs extend, nearly touching in the middle. Can you notice that your hands are now forming a triangle shape on the centre of your pelvis?  For a neutral pelvis, the triangle lines should be on the same plane, aligning these three bony landmarks.

When working with students, it’s good to keep in mind though that anatomical differences may occur from dancer to dancer, therefore the triangle alignment should be a reference for finding an individual neutral pelvis.

Pelvic deviations generally imply any alteration in posture from neutral but when it comes to dancers, anterior pelvic tilt (that is allowing the tailbone to flare backwards) appears to be more common.

Why is that?

Misalignment of the pelvis could be related to imbalanced use of muscles that control the pelvis, the lower portion of the trunk and hip, or to structural conditions.  Particularly, anterior pelvic tilt could be linked to lack of action of the deep rotators of the hip for turning out (we’ve mentioned before the key role that these muscles play, recap here. The misuse of the inner thigh muscles or poor core control to stabilize the turnout may increase this deviation still more (for more about the core check this post).

Dancers with anterior pelvic tilt might get tight hip flexors and possibly lower back pain, as it increases the angle of lumbar lordosis. Posterior pelvic tilt (tucking the tail under) is typified by a flat back-like deviation and commonly associated with tight hamstrings and gluteal muscles and weak quadriceps, hip flexors and spinal erectors. Generally, dancers with a misaligned pelvis either anteriorly or posteriorly can more easily develop vertebral stresses and knee, foot, and ankle injuries due to compensatory movements and excess of muscle tension during training.

Despite all the information available on pelvic alignment, there is still a question to be answered: Is there an ideal degree of pelvic tilt that should be maintained through our dance movements?  Pelvic mobility in dance seems to be a hot topic of discussion among dance practitioners, teachers and scientists. Undoubtedly, there are many steps that intentionally involve the pelvis (either as initiator of the action as observed in Graham Technique for example, or as a consequence of another movement). However, we know that some techniques  require  that some specific movements should be performed with neutral (or even immobile) pelvis. I wonder though to what extent the pelvis really is immobile in such movements?

In relation to this, Wilson and colleagues looked at a grande rond de jambe en l’air. In our training, most of us learned that the pelvis should be still for the whole time during grande rond de jambe en l’air both at and past 90°. Yet these researchers observed that amongst experienced dancers the pelvis itself is deeply involved in gesture leg range of motion, especially when the leg is raised past 90°. In order to move the leg fully at highly vertical angles, the pelvis seems to follow the leg - even though we aim for creating an illusion of an immobile pelvis.  In a follow-up study the role of the pelvis was examined in facilitating gesture leg motion, and the related “cost” of the muscles involved. For skilled dancers the effort in the gesture leg is smaller than in the standing leg. This was reversed in less skilled dancers. So we might conclude that the skilled dancers worked more efficiently in their standing leg to support the pelvis and gesture leg, whereas the less skilled dancers are mostly using the muscles in the gesturing leg.  A recommendation to the teacher might be to appreciate that when working on movements where one leg is moving fully, a strategy to focus on the standing leg will help balance the necessary movement in the pelvis and spine. Not allowing the pelvis to move commensurately with the gesturing leg will decrease the potential range of motion and place unnecessary stress on the hip joint and lumbar spine.


Source: Getty Images

But what about other movements where the pelvis should be neutral? Deckert suggests that the answer is multifaceted and individualized to each dancer. Introducing exercises for dancers which focus on increasing awareness through individualized anatomical education, motor control and promoting alignment habits may help dancers locate the neutral pelvis.

Integrating the following exercises into a dancer’s daily routine may also help:

• Increase abdominal strength; strong abdominals provide support for finding and maintaining a neutral pelvis.

• Stretch hip flexors, if they have become excessively tight from years of anterior pelvic tilt. Stretching them on a daily basis will allow the pelvis to settle into a more neutral position.

• “Pelvic clock” provides a first step toward improvement by increasing awareness of pelvic alignment: Lying on your back with knees bent and feet on the floor, tip the pelvis through full range of motion, starting at 12 o’clock with the navel and lower back pressed to the floor and moving through to 6 o’clock as the waist rises off the floor and the tailbone is the only part of the spine contacting the floor. Make certain not to miss any point of the clock, and repeat in a counterclockwise circle. This exercise forces you to explore the full range of motion available in the pelvis and find a neutral pelvic alignment.

What I enjoy the most about the quest for finding movement efficiency in dance, is that it always awakens further inquiry; which movements involve pelvic motion? Which should hold a neutral pelvis? Which body part is leading, following or supporting movement?

 

Keep Exploring:

IADMS Resources here and here.

 

Clara Fischer Gam, MSc.

Dance Science

Dance Education

Pilates Method

Rio de Janeiro – Brazil

Email: clara.figa@gmail.com

 

Elsa Urmston MSc PGCAP AFHEA is the DanceEast Centre for Advanced Training Manager, Ipswich, UK and a member of the IADMS Education Committee.

Email: elsa.urmston@danceeast.co.uk

Tags:  anatomy  dancers  pelvis  teachers 

PermalinkComments (0)
 

The Pelvis: The Meeting Point of the Body

Posted By Clara Fischer Gam on behalf of the IADMS Education Committee, Monday, April 27, 2015

We will get the week started with a post from the IADMS Education Committee. This is part 1 of a two-post discussion on pelvic structure and alignment. Today we will take a closer look at anatomy of the pelvis and share ideas for embodying these concepts in the studio.

 
Source: Getty Images

The pelvis as the “meeting point” of the body is a really clear analogy, as it is this structure that offers attachment for the legs and supports the spine and upper limbs. It plays a key part in bearing and transferring weight, it allows us to travel with dynamism as well as find balance and stability in the body.  Experiential anatomy allows us to really develop a sound working knowledge of the anatomical structure; linking theoretical knowledge and practical exercises in class can be really useful for developing movement strategies, enhancing quality and intention for dance technique.

So, how is the pelvis structured?

The pelvis is made up of two halves, the innominate bones (or simply, hip bones). Each one is formed from the fusion of three bones: ilium, pubis and ischium. Together, these three bones contribute to the hip socket that connects the pelvis to the femur (more about the hip joint in a previous post). 



Diagrams by Jake and Stuart Pett for IADMS

Anteriorly, the hip bones are connected by the symphysis pubis, a cartilaginous joint. Posteriorly, they connect to the sacrum through the sacroiliac joint. The upper part of the sacrum connects with the 5th vertebra of the lumbar spine (lumbosacral joint). For a more comprehensive anatomy of the pelvis, check out this great video.  

To bring about a more embodied knowledge of pelvic bones, I often encourage students to make use of touch as we go through anatomy concepts. Bone palpation activities can be easily applied to class when exploring anatomy of the pelvis. The author Andrea Olsen offers us a good suggestion:

Starting at a supine position, knees bent: trace the bones of the pelvis with the finger tips.

Firstly at the iliac crest, find the anterior superior iliac spines (ASIS), those bony projections at the front part of each hip bone. Then walk the fingers forward until the pubic symphysis.

Roll on your side: starting again at the iliac crest, trace the ilium back to the sacrum, feel the sacroiliac joint. Continue down the back of the pelvis and locate the ischial tuberosities (the "sitz" bones).

Flex the hip, and trace from the ischium to the pubic bone between the legs. Roll to the other side and repeat. You can find more experiential anatomy exercises on Olsen’s book, referred below.

 

Mainly, the pelvis moves as a whole: articulation occurs at the lumbosacral joint and at the heads of the femurs. It tilts anteriorly (allowing the tail bone to flare backward) posteriorly (tucking the tail bone under), laterally (lifting one side of the waist) and it also rotates (turn) for both sides. When watching students dancing, we may notice that ease of movement as well as restrictions for specific directions vary from dancer to dancer.

At a natural position in relation to the rest of the body, the pelvis is in the so-called neutral position: known for being the most stable and shock-absorbing for our structure, as surrounding joints and muscles are balanced.  Watch out for our next post, where we will discuss the importance of pelvic alignment for optimal performance! 

Something I really like to do to explore pelvic articulation and positioning is to practice the pelvic clock exercise as a warm-up in class (typical routine of Feldenkrais and Pilates sessions). That way, dancers can experiment with pelvic movements, discovering their own range of motion, restrictions and ultimately find their neutral pelvis. Watch a tutorial here.

 

Keep Exploring:

Olsen, A. Bodystories: A Guide to Experiential Anatomy. Lebanon: University Press of New England, 1991.

Calais-Germain, B. Anatomy of Movement. Seatle: Eastland Press, 2007.

Fitt, S. Dance Kinesiology. New York: Schirmer Books, Second Edition, 1996.

Salk, J. Teaching modern technique through experiential anatomy. Journal of Dance Education. 2005;3(3): 97-102.

Batson, G. Somatic studies and  dance. International Association for Dance Medicine and Science, 2009. Available here.

 


Clara Fischer Gam, MS.

Dance Science

Dance Education

Pilates Method

Rio de Janeiro – Brazil

 

Email: clara.figa@gmail.com

 

 

Tags:  anatomy  dancers  pelvis  teachers 

PermalinkComments (0)
 

Core Control: “Not just abdominals”

Posted By Clara Fischer Gam on behalf of the IADMS Education Committee, Monday, March 16, 2015

 

In previous Education Committee posts we’ve spent time talking about turnout, and mentioned the importance of core control and neutral alignment in maximizing rotation of the legs.  Here, we spend a bit more time focusing on core control and what that might mean.

Everyone is talking about the importance of core control and the topic is becoming commonplace among dancers and teachers. We keep hearing that dancers got to have “core awareness,” “strong abdominals,” and “movement control.” Before we start “drawing our belly buttons in” we might well ask ourselves: 

What does core control actually mean?

The term core usually refers to the structures (including bones, muscles and ligaments) of the shoulder girdle, trunk, pelvis and hip. As the human spine is in essence an unstable structure, further stabilization is provided by the musculature.

There is still some debate within research about the muscles that constitute the core and their precise contribution to movement control, but here we will meet muscle groups that are often considered by researchers to be involved in the dynamics of core control:

Superficial muscles of the trunk: They produce trunk motion and act as prime movers during dynamic activities and provide multi-segmental stiffness over a wide range of motion (e.g.: rectus abdominis, external and internal obliques, iliocostalis thoracis).

Deep muscles of the trunk: These local muscles are better suited for segmental stability (e.g.: transversus abdominis, multifidus, interspinalis).


Transfer Muscles of the Shoulder Girdle and Pelvic Girdle: These muscle groups connect the upper or the lower limbs to the trunk thereby transferring the forces through the system during movement (e.g.: hip flexors, scapular stabilizers)


Above: Serratus anterior, example of transfer muscle of the shoulder girdle

 

Above: Psoas major and iliacus, examples of transfer muscles of the pelvic girdle

Pelvic Floor Muscles: These muscles are part of the compound structure that closes the bony pelvic outlet, offering support to the pelvic organs (e.g.: urogenital sphincter, levator ani)

As superficial muscles can be easily accessed, we tend to rely on them maybe more frequently than we should (e.g.: feeling only the “six pack” rectus abdominis activation without regard for the deep abdominals when “contracting” in Graham Technique class). Although deep muscles are not as easy to feel and recruit as superficial muscles, they’ve got an important function. Teachers can encourage students’ awareness for these deeper muscles (e.g.: they can be reminded of the action of transversus abdominis as well as of superficial muscles involved while reaching a penchée).

What then?

These diverse muscle groups act together to maintain control of positioning and movement of the trunk over the upper and lower extremities: and that’s especially relevant when it comes to dance. Core control seems to provide spine support and to back up pelvic alignment, which could be important factors to ensure movement control of legs and arms as well as to facilitate turnout in dancers.  You can find some ideas for core support training directed to turnout on this International Association for Dance Medicine & Science (IADMS) Resource Paper HERE.  Also check out our previous blog posts for bite-size information HERE.

Lack of core control seems to increase strain on the surrounding joints, bones and ligaments and has been related to injury risk on lower extremities and the lower back. As we know that dancers quite often acquire injuries on these parts of the body, bringing core control activities into studio practice could also play a key role on injury prevention and in turn enhance movement efficiency.

When cueing dance students to navigate through the core concept, it’s important to keep in mind that as postural adjustments and external loads entail constant changes to the body, core stability is considered a dynamic concept. That means that the contributions of each muscle on maintaining trunk stability may vary moment to moment throughout movement. For this reason, it’s hard to say that there is such a thing as a single core muscle we should always focus on while dancing. The core control muscles appear to work synchronously with one another.

Instead, it could be really useful (and fun) to explore the strategies used to achieve a desired movement you are working on and observe the muscle activation patterns it causes, whilst keeping in mind the anatomical references as well as research findings and discussions about core control. Why not help young dancers themselves to feel their core throughout movement and to identify their personal patterns during class? Kitty Daniels talks about strategies to help students to understand the role of core control in practice as well as to find a system of their own to work on individual challenges and artistic goals. Find out more about this teaching approach at this IADMS Bulletin for Teachers article HERE, click on Bulletin Volume 1, Number 1, pages 8-10.

As we’ve mentioned before providing images and online applications which allow dancers to locate these muscles really seems to aid understanding and importantly, the efficient execution of movement. Check out these short animated videos: they are great resources in locating those deep control muscles, which are often so difficult for dancers to feel.

Keep exploring:

Ambegaonkar JP, Rickman AM, Cortes N. Core stability: implications for dance injuries. Medical Problems of Performing Artists. 2012;17(3):143-148.

Cholewieki J & McGill SM. Mechanical stability of the in vivo lumbar spine: implications for injury and chronic low back pain. Clinical Biomechanics. 1996; ll(l):l-15.

Hodges PW & Richardson CA. Contraction of the abdominal muscles associated with movement of the lower limb. Physical Therapy.1997; 77(2):132-142.

Kline JB, Krauss JR, Maher SE, Quo X. Core strength training using a combination of home exercises and a dynamic sling system for the management of low back pain in pre-professional ballet dancers. A case series. Journal of Dance Medicine & Science. 2013; 17(1):24-33.

Panjabi M. The stabilizing system of the spine. Part II. Neutral zone and instability hypothesis. Journal of Spinal Disorders. 1992; 5(4):390-397.

Clara Fischer Gam, MS.
Dance Educator, Pilates Instructor
Rio de Janeiro, Brazil
Email: clara.figa@gmail.com

Tags:  anatomy  dancers  teachers  turnout 

PermalinkComments (0)
 

To torque or not to torque: The summative contributions of the knee, tibia and foot in the use of turn out

Posted By Maggie Lorraine on behalf of the IADMS Education Committee, Monday, February 23, 2015

In a previous post we examined the structure of the pelvis and hip joint and observed how the anatomical variations of the structure can impact on an individual’s ability to externally rotate their legs in the hip socket (turnout). We know that in most cases, dancers do not possess perfect turnout or complete external rotation from the hip. Often turnout is viewed as the placement of the prescriptive positions of the feet on the floor, however it is important to remember that turnout is an aligned movement of the whole leg from the hip joint culminating in the centering of weight over the foot on the floor whilst dancing. Ergo turnout is an action not a static position.

Dr. William Hardaker and Dr. Lars Erick, in a paper delivered with Martha Myers to the 1984 Olympic Scientific Congress, estimated that the 180° turnout is achieved by 60°-70° rotation of the leg from the hip and the remaining 40°-30° is picked up by the knee, tibia and foot. At the tibia, torsion is defined as an axial twist of the tibia or shinbone. Dancers in their growth years may develop external tibial torsion as a result of turning out their feet beyond the range of the hip joint. The torsion has been measured as widely varied as 16° to 60° and also with differing amounts of tibial torsion in each leg.

The small bones in the foot allow a gliding action to occur at the arch and it is not uncommon to see dancers force the lower limbs beyond the normal limits of the hip’s range of motion, creating a compensating action called pronation or “rolling in” of the feet to achieve the perception of greater or perfect turnout. The injury rate for the foot and ankle complex is the highest of all joint systems and the illustration below clearly indicates the risk potential. Note the change to the alignment of the Achilles tendon and the weight distribution on the inside of the foot as a result of the pronation of the foot.

IMAGE WILL RETURN SOON

Many factors contribute to the safe and efficient control of turnout whilst dancing. Rather like a team, body alignment, core control and the recruitment of muscle groups, which activate and control turnout, all play their integral part. Should one part fail there is a chain reaction that effects the efficiency of the others.

Many years ago I learnt what was for me is the golden rule of alignment and turn out. The weight of the body should fall like gravity, through the centre of the bones and the weight of the body is evenly distributed over the feet on the floor. This ideology creates stability, strength and control in a way that would be difficult to achieve through the action of torsion of the knee, tibia and pronated foot. The bonus of the aligned mode of working, is that turnout can be improved by the efficient recruitment and strengthening of the turnout muscles and the intrinsic foot muscles supporting the body weight on the floor.

Follow these links for more information:

Information for this article has been drawn from the IADMS Resource Paper

The following IADMS link provides an excellent training program for dancers:

Further reading:

Grossman G, Krasnow D and Welsh TM. Effective use of turnout: biomechanical, neuromuscular, and behavioral considerations. Journal of Dance Education 2005;5(1):15-27.

Maggie Lorraine is the Leading Teacher in Ballet at the Victorian College of the Arts Secondary School and is a member of the IADMS Education Committee.

Tags:  anatomy  dancers  teachers  turnout 

PermalinkComments (1)
 

Approaching turnout with young dancers: Muscles that rotate the leg

Posted By Elsa Urmston on behalf of the IADMS Education Committee, Monday, February 2, 2015

 

All too often we see our young dancers forcing their turnout in an attempt to achieve the illusive 180 degree line of the feet whilst often compromising the neutral line of the spine and pelvis and putting the knees, ankles and feet at high risk of injury.

The last blog post by the IADMS Education Committee focussed on the anatomy of the hip joint; this time we take a look at the muscles which govern turn out and the lateral rotation of the hip. Knowing which muscles do what can help young dancers especially work more efficiently; talking about the location and function of those muscles and showing images of them can really inspire children and young people to maximise the rotation of the hip whilst working safely and effectively. And reminding them that there are no turnout muscles in the feet is a light-hearted reminder of how turnout should work! There are some great applications available which can help our dancers to clearly understand the anatomy and musculature of turnout, and are well worth bringing into the classroom, such as 3D for Medical Muscle System and VisibleBody. 

Whilst the most obvious muscles of the hips are located in the buttocks, the muscles that are vital for turnout are the six deep lateral rotators, buried under the gluteal muscles and deep within the pelvic girdle. Identifying and recruiting these muscles can be tough and we often see an over-recruitment of the gluteus maximus in an effort to rotate the legs, both when standing and gesturing the leg in a non-weight-bearing position. The deep lateral rotators aid the efficient rotation of the leg, running laterally across the back of the hip joint capsule. They all attach on or adjacent to the greater trochanter of the femur and achieve rotation by pulling the greater trochanter backwards, towards the back of the pelvis. As well as the diagrams below, take a look at this great animation which demonstrates the location and function of these muscles in hip rotation.

Other muscles contribute to the rotation of the leg too. The sartorius is thought to help turn out the leg when the hip is flexed or abducted such as in retiré or attitude devant. And the inside thigh muscles (adductors) may also contribute to the rotation of the legs when they are extended and already turned out by the deep lateral rotators. In class I tend to talk about the adductor muscles lengthening to aid the rotation of the leg, especially when the leg is extended to second; this tends to bring about less tension and ensures that the deep lateral rotators remain the primary rotators of the legs, both when weightbearing and gesturing the leg.

 

It is important to remember that external hip rotation and turnout are not really the same thing. Anatomically, 60% of turnout is achieved by the outward rotation of the hip. The rest tends to come from the ankle, followed by the knee joint and tibia itself. 

The problem here of course is when those deep rotators are not recruited first. This, coupled with anatomical factors which hinder the rotation of the leg, can mean that the dancer screws the leg from the foot upwards in a bid to achieve that 180 degree line of the feet I mentioned earlier. This places huge torsion on the big toe joint, ankles and knees – a recipe for greater likelihood of injury. The knock on effect of this screwing action also often means that the alignment of the pelvis and spine are compromised. So, the use of core support and an awareness of pelvic alignment are also crucial if turnout is to be fully functional in dynamic dancing. The recruitment of the deep rotators and the stability of controlled foot placement on the floor are the key elements for the safe recruitment of turnout whilst dancing.

There is a range of specific exercises for conditioning the turnout muscles, and for helping dancers to recruit the primary and supporting muscles involved in rotating the leg and maintaining efficient alignment of the spine and pelvis. Take a look at the IADMS Resource Papers for lots more information and ideas to take into class:

·         Turnout for Dancers: Hip Anatomy and Factors Affecting Turnout

·         Turnout for Dancers: Supplemental Training

 

Further Reading:

Grossman G, Krasnow D and Welsh TM. Effective use of turnout: biomechanical, neuromuscular, and behavioral considerations. Journal of Dance Education 2005;5(1):15-27.

 

 

Elsa Urmston, MSc, PGCAP, AFHEA, is the DanceEast Centre for Advanced Training Manager, Ipswich, UK and a member of the IADMS Education Committee.
Email: elsa.urmston@danceeast.co.uk

 

Tags:  anatomy  dancers  teachers  turnout 

PermalinkComments (2)
 

What has the “Anatomy of the Hip Joint” got to do with Louis XIV?

Posted By Maggie Lorraine on behalf of the IADMS Education Committee, Tuesday, January 13, 2015

Classical Ballet is a dynamic art form. The art of ballet has undergone change since its birth in the mid-17th to early 18th Century. It is interesting to review the description of the organization of the body, codified by Pierre Beauchamp (1631-1705). The five positions of the feet are described as turned out from the hip to an angle of 45 degrees. It was emphasized that the feet should never be turned out more than 45 degrees.

Over time, there has developed an expectation for Ballet dancers to turnout each foot to 90 degrees creating a 180 degree shape with the feet.  By studying human anatomy it appears that Beauchamp was more anatomically sound in his recommendation of the 45 degree turn out “from the hip” than the current 180 degree placement “of the feet” that we now often see.  There are many anatomical factors contributing to the effective use of turn out.

The Bone Anatomy of the Pelvis

The pelvis is formed from the fusion of three bones: ilium, pubis, and ischium. Each of the three bones contributes to the hip socket or acetabulum.


The Ball and Socket

The hip joint includes two main parts, the ball and socket. The ball of the hip joint consists of the round head of the femur or thigh bone and the femur articulates with the hip joint to enable the leg to rotate outwards.

There are three factors that affect turnout from the bony structure of the hip joint and most researchers agree that these conditions cannot be altered with training:

1.      Angle of femoral anteversion

On average, the neck of the femur is angled 15 degrees forward relative to the shaft of the femur (see Figure 3A). An increase in this anterior angulation, called anteversion, often will cause someone to toe in when they walk, (see Figure 3B). People who are born with more anteversion, the orientation of the femoral shaft in the hip socket makes the knees face towards each other when standing or walking. In ballet class, when they turn out their legs from the hip, the knees face the front, leaving little additional hip rotation to create the expected angle of outward rotation visible at the feet.

However, a decrease in this angulation, called retroversion, will allow one to have greater turnout (see Figure 3C). People born with retroversion have a much easier time with turnout. Just standing in neutral, the knees and feet tend to face outward. By adding external rotation at the hip, they can achieve a larger angle of outward rotation visible at the feet than the average person.


2.      Orientation of the acetabulum

The socket of the hip faces out to the side and somewhat forward.  The socket that tends to face more directly to the side with a less forward facing will allow a greater amount of turnout to come from the hip therefore greater movement range.

3.      Shape of the femoral neck

The neck of the femur is subject to some variability. A longer and more concave neck allows a greater range of motion at the hip and is therefore considered to be advantageous.  A shorter and less concave neck will have the opposite effect and limit turnout resulting in less movement range.

Bearing these anatomical differences in mind, it is more important to encourage dancers to use the turnout they have, rather than working against their anatomical make-up to achieve an unrealistic position.  Louis XIV was happy with 45 degrees, we can safely move beyond that if we apply a good understanding of anatomical structure and function.

Further Resources:

Wilmerding V, Krasnow D.  Turnout for Dancers - Hip Anatomy and Factors Affecting Turnout, IADMS Resource Paper. 2011.
Available HERE

Krasnow D, Wilmerding V. Turnout for Dancers – Supplemental Training. IADMS Resource Paper. 2011.
Available HERE

A useful tutorial on the hip joint, range of motion and function:
Sechrest R. Hip Anatomy Animated Tutorial, 2012.
Watch it HERE

A great tutorial on hip function in squats with additional images on bone structure, which may govern why people may need to approach movement in different ways:

De Bell R. The Best Kept Secret: Why People Have to Squat Differently, 2015.
Watch it HERE

Tags:  anatomy  dancers  hips  teachers  turnout 

PermalinkComments (0)
 
Association Management Software Powered by YourMembership  ::  Legal