Introduction
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Dance is an activity that can be found in most cultures dating back to ancient times.
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Dance is unique in its fusion of art and athletic activity.
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It can increase cardiorespiratory fitness, muscular strength and endurance, flexibility, and bone mineral density.
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Classical ballet provides a foundation for other dance forms, and historically, considerable amount of research has focused on ballet. However, in recent years, interest and research in other forms of dance has increased.
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Other popular forms of dance include contemporary (modern), jazz, hip hop, tap, Irish, folk dance, and ballroom.
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Although there is some crossover, each of these forms has unique features and injury profiles.
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Epidemiology
A 2011 study of American adolescents found that 20.9% participated in dance, making it the third most common physical activity in girls.
Ballet
Demographics
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Professional female ballet dancers often start classes between ages 4 and 9, with males starting between ages 12 and 16.
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Preprofessional ballet training begins at about age 11 but can start as early as age 8.
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There is an increase in the duration and intensity of training.
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Training is conducted 5–6 days per week, ranging from 6 to 45 hours per week.
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The average age for professional ballet dancers is 26 to 27 years.
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The average female body mass index (BMI) is 18 to 19; that for males is 21 to 22
Injuries
Frequency
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Injury rate: 75%–95% of ballet dancers suffer at least one injury per year, with an average of 3.0 to 3.2 injuries per dancer per year
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1.09 to 3.52 injuries per 1,000 dance exposures
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0.6 to 4.4 injuries per 1,000 hours of training
Type
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53.6%–85% of injuries are from overuse, and 12%–45% from acute trauma
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Most injuries are of muscle strains, followed by ligament sprains and chronic inflammatory processes.
Severity
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The average time lost to injuries is 32.5 days in females and 21.6 days in males.
Anatomic Location of Injury
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Most common: foot and ankle, low back, hip, and knee
Risk Factors
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Intrinsic risk factors for dance-related injuries include: anatomic structure, inadequate strength and flexibility, improper technique, nutrition, previous injury, fatigue, inadequate turnout, higher rate of growth, female gender, and disordered eating behaviors.
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Extrinsic risk factors include: choreography, cold environment, dance floor properties (e.g., surface, resilience).
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Students in summer intensive programs are at high risk of injury due to the sudden increase in hours of activity.
Modern
Demographics
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Professional female dancers start taking dance class at 6.5 years of age, while male dancers start at 15.6 years of age.
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Most professional female modern dancers began their dance careers by studying ballet, whereas men began by studying modern.
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The average age for female professional modern dancers is about 30 years; that for males is 31 years.
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The average BMI for females is 20.6; that for males is 23.6.
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Professional modern dancers study various forms of dance, including ballet, pointe, jazz, tap, hip hop, African, and ballroom, outside the time they spend in rehearsal for their companies.
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They spend an average of 8 hours taking various types of dance classes and about 17 hours in rehearsals for their companies.
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Most dancers also spend about 2 to 3 hours per week doing some form of exercise outside of dance such as yoga, Pilates, Gyrotonics, weightlifting, running, biking, and walking.
Injuries
Frequency
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Up to 82% suffer injuries per year
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The annual incidence of injury is 1.2 in males and 1.7 in females.
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Injury rate: 0.6/1,000 hours of dancing
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The majority of injuries occur in class, followed by rehearsal and performance.
Type
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Most injuries result from overuse or gradual onset (57%) rather than as a consequence of an acute or traumatic event (43%).
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The most common injury types are: muscle strains, followed by ligament sprains, and then other chronic inflammatory processes.
Severity
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Dancers can return to partial dancing after an average of 2–3 weeks post injury.
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Returning to full dancing can take an average of up to 2 months.
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Modern dancers admit to returning to dance with pain.
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Males miss fewer classes and rehearsals as a result of injury than females.
Anatomic Location
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The most common sites of injury in descending order are: ankle, low back, knee, and foot.
Risk Factors
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Intrinsic risk factors: self-pressure, ignoring pain and fatigue
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Extrinsic risk factors:
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The demands of the role and from the choreographer
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Floor characteristics: surface, resilience, raked or not (floor angled down to audience for better viewing)
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Injury Consultation
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Most dancers will consult with someone within 1 week of injury.
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Fewer than half of the dancers will consult with a physician regarding the injury because they either think that physicians are neither helpful nor understanding of them as dancers; or the dancers do not have health insurance, or are concerned that they will be told to stop dancing for too long. Many dancers consult other healthcare providers such as company physical therapists, chiropractors, massage therapists, and acupuncturists. Many will also discuss their injuries with a member of the company such as the choreographer, company director, or instructor.
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Most dancers actually adhere to the advice given to them.
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Their main reasons for not adhering to the advice given to them include: the lengthy amount of time recommended to refrain from dance, fear of being held out of class or rehearsal if the staff knew about the injury, not agreeing with the advice, and fear of losing their role in the performance to an understudy or rival.
Irish
Demographics
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Became mainstream in 1994 following the production of Riverdance and subsequent professional touring shows
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The age of professional dancers ranges between 17 and 34 years.
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The mean age of dancers first turning professional is 18.5 years.
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The age of competition-age dancers generally ranges from 4 to 21 years.
Injuries
Frequency
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Up to 60% professional Irish dancers have suffered injuries.
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Up to 80% of competitive level Irish dancers have suffered injuries.
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The lifetime risk of injury can be as high as 90%.
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79.6% of injuries are categorized as overuse or chronic.
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20.4% of injuries are categorized as traumatic or acute.
Type
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In descending order of frequency: tendon injury, apophysitis, patella pain or instability, stress injury, strain, and sprain
Location
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95% of injuries involved the lower extremities. Frequency in descending order: foot, ankle, knee, and hip
Risk Factors
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Intrinsic: fatigue or overwork, ignoring early warning signs, improper or lack of warm up and/or cool down
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Extrinsic: accident, unsuitable floor, repetitive movement, unsuitable foot wear
General Priciples
Terminology
Arabesque: A pose in which the dancer stands on one leg and raises the other straight behind (at various angles); usually one arm is stretched out in front ( Fig. 92.1 )
Figure 92.1
Common terms in dance.
(Photographs courtesy of Craig C. Young, MD and Selina Shah, MD.)
Class: Lesson
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Barre—the first part of ballet class conducted using the railing for balance and technique training
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Center—the portion of class in which dancers perform dance movements in the “center of the room” without using the barre for assistance
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Across the Floor: A series of choreographed steps performed diagonally across the room in small groups, with choreography done on the right side in one direction and on the left side in the other
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Demi-pointe: The foot is maximally plantar flexed with toes maximally extended—weight on metatarsal heads.
Foot positions: (see Fig. 92.1 )
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First position—feet turned out with heels touching
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Second position—feet turned out with heels apart
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Third position—feet turned out, overlapping with right heel in hollow of left foot
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Fourth position—feet turned out, apart but with overlapping heels
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Fifth position—feet turned out, touching with right heel in front of left toe
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Jeté: A jump where the legs are in a split position in the air
Plié: Bending of the knees and ankles with the legs turned out
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Grand plié—a large or deep plié where the knees are maximally flexed and the feet are in demi-pointe (see Fig. 92.1 )
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Demi-plié—a “small” plié where the knees are only partially flexed and the feet are flat on the floor (see Fig. 92.1 )
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Pointe: Dancing while supporting the body on the tips of the toes (see Fig. 92.1 )
Relevé: To rise up to the tiptoes or full pointe
Turnout: A stance in which legs are rotated outward. Turnout is the sum of the external rotations of the hip, knee, tibia, ankle, and foot.
Types of Dance
Ballet
Background
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Classical ballet originated in the 1400s in Italy and blossomed in the 1600s in France.
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Traditionally, professional ballet companies perform story ballets. Some of the most famous ones are The Nutcracker (usually performed during Christmas), Swan Lake , and Giselle. They also will perform mixed programs consisting of a variety of choreographed dances.
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Ballet is a choreographed series of specific motions, with specific placement of all body parts from the head to the toes.
Technique
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Many positions require extreme external rotation of the hips (see Fig. 92.1 ).
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Flexibility is required to achieve 180 degree splits of the legs.
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Strength is required to hold the legs in extreme positions of hip flexion and in extension with extended knees and plantarflexed ankles and toes.
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Dancing on pointe consists of dancing while supporting the body on the tips of the toes. This is almost always done by women, but there is one professional male company, as well as a few other choreographed dances, where males perform pointe work.
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Most young female dancers aspire to go on pointe.
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Adequate skill, technique (including balance and core stability), alignment, maturity to apply teacher corrections, and at least 90 degrees of ankle plantarflexion to achieve full pointe are the basic requirements. More sophisticated tests that examine the dancer’s ability to maintain proper alignment and balance while performing ballet jumps and combinations may also be useful ( Fig. 92.2 , relevé passé).
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