Dance training intensity at 11-14 years is associated with femoral torsion in classical ballet dancers

[Dance-specific eligibility of vocational ballet students - examinations at a governmental training institution for classical ballet]

BACKGROUND

During their training, pre-professional ballet students are confronted with physical stresses comparable to those of competitive sports. In competitive sports, there are mandatory and binding aptitude tests to ensure that the growing athlete meets the requirements. In ballet, there are no such mandatory examinations preceding the start of training. For adult professional dancers, musculoskeletal ideals could be isolated from the dance medicine literature. However, only a few studies describe musculoskeletal characteristics of pre-professional ballet students. It is neither known at what age a student should meet the ideal measurements for an adult nor what deviations from the ideal can be considered normal. This study aims to describe sociodemographic and musculoskeletal characteristics of pre-professional ballet students and discusses to what extent they already meet or deviate from dance-specific eligibility criteria for adult professional ballet dancers.

MATERIAL AND METHODS

In this study, n = 414 female and n = 192 male students of John Cranko School (JCS) were seen by an experienced orthopaedist and dance physician. Mean age was 13.9 years (SD 3.5, range 5-22 years). Their medical history was taken (age; nationality; start of ballet/training) and a physical examination was performed (height/weight; symmetry of shoulder girdle, spine, waist triangles; pelvic tilt; tibial torsion; range of motion of base of index finger joint, spine, hips, ankle and base of great toe joint). Subsequently, the results of this study were compared with suitability criteria for adult professional ballet dancers that had been isolated from the dance medicine literature for a previous article.

RESULTS

Examinees were from 49 different nations. 34.6% of the female subjects (≥16 years) were between 165 and 170 cm and 33.3% of the male subjects (≥18 years) were between 178 and 185 cm tall. 45.0% of those examined showed low body weight (<10th percentile, BMI <18.5 kg/m²). The trunk of 61.0-84.8% of those examined was erect and symmetrical. 25.2% had scoliosis. Half (53.5%) were found to have a bilateral external rotation of the hips of at least 60°, and 68.7% had a bilateral internal rotation between 20 and 50°. 87.3% exhibited a bilateral tibial torsion between 15 and 40°. A bilateral en dehors of 90° was calculated for 25.0%. In 9.1% of those examined, the upper ankle joints presented a dorsiflexion of at least 25°, and in 70.2%, a plantarflexion of at least 70° was seen. In 88.0%, the metatarsophalangeal joint of the great toe was 90° (f) and 80° (m) on both sides.

CONCLUSION

The results of this study showed that pre-professional ballet students fulfil many characteristics of adult professional ballet dancers. High values already among young age groups suggest a ballet-specific selection. Nevertheless, not all students fulfil the theoretical "ideal measurements" for professional classical ballet. These anatomical limits should be considered individually in training to protect the growing pre-professional ballet dancer. The high ballet-specific anatomical demands, but especially the large number of students with a low body weight, underline the necessity of mandatory aptitude tests at the beginning and regular check-ups in the course of training to avert compensatory mechanisms and their consequential damage and to screen for eating disorders and disorders of eating behaviour.

Feasibility of mitigating out-toeing gait using compression tights with inward-directing taping lines

Out-toeing gait may cause alterations in lower limb biomechanics that could lead to an increased risk of overuse injuries. Surgery and physical therapy are conventional methods for mitigating such gait, but they are costly and time-consuming. Wearable devices like braces and orthoses are used as affordable alternatives, but they apply non-negligible stress on the skin. Haptic feedback-delivering shoes were also recently developed, but they require actuators and power sources. The purpose of our study is to develop compression tights with inward directing taping lines that apply compression to lower limb muscles and segments to facilitate inward rotation of the foot, overcoming the drawbacks of previous methods. These compression tights were manufactured to fit the average height, leg length, hip girth, and waist girth of South Korean females in their twenties. The efficacy of these compression tights was evaluated by comparing walking kinematics and user satisfaction of 12 female dancers with an out-toeing gait under three conditions: wearing tights with taping lines, tights without taping lines, and basic bicycle shorts. The foot rotation angles and joint kinematics were recorded using a pressure-pad treadmill and motion capture system, respectively. Multiple pairwise comparisons revealed that the compression tights with inward-directing lines significantly reduced foot rotation angles (up to an average of 20.1%) compared with the bicycle shorts (p = 0.002 and 0.001 for dominant and non-dominant foot, respectively) or the compression tights without taping lines (p = 0.005 and p = 0.001 for dominant and non-dominant foot, respectively). Statistical parametric mapping revealed significant main effects of the tight type on joint kinematics. Also, t-tests revealed that the participants reported significantly higher ratings of perceived functionality and usability on the compression tights with inward-directing taping lines. In conclusion, we developed a comfortable and practical apparel-type wearable and demonstrated its short-term efficacy in mitigating out-toeing gait.

Pediatric Dance-Related Injuries Treated in Emergency Departments in the United States, 2000-2020

OBJECTIVE

This study investigated the characteristics and trends of children aged 3 to 19 years treated in US emergency departments for dance-related injuries.

METHODS

Retrospective analysis of data from the National Electronic Injury Surveillance System from 2000 through 2020 was conducted.

RESULTS

An estimated 489,119 children received emergency treatment for a dance-related injury, averaging 23,291 children annually, and the rate of injury increased 68.1% during the 21-year study period. Girls accounted for 80.3% and children aged 15 to 19 years accounted for 46.5% of cases. Sprains/strains were the most frequent diagnosis (44.4%), and lower extremities were the most commonly injured body region (56.4%). Compared with other body regions, patients aged 3 to 10 years were more likely to sustain head/neck injuries (odds ratio, 3.94, 95% confidence interval, 3.42-4.52) than 11- to 19-year-olds. Falls and noncontact mechanisms of injury accounted for 35.6% and 32.1% of injuries, respectively. Unstructured dance activity was associated with 30.8% of dance-related injuries overall and 67.0% among children aged 3 to 5 years. Ballet/pointe dancers frequently sustained lower extremity sprains/strains (39.2%). Compared with other dance types, break dancing was more commonly associated with injuries to an upper extremity than other body regions (odds ratio, 4.76, 95% confidence interval, 3.66-6.19).

CONCLUSIONS

The rate of pediatric dance-related injuries treated in US emergency departments is increasing. Unstructured dance activity was an important source of dance-related injury, especially among children aged 3 to 5 years. The injury diagnosis and body region injured varied by child age and type of dance. Additional targeted prevention efforts should be implemented that address the injury characteristics of dancer subgroups.

Is there an association between joint range of motion and muscle strength in young female dancers? And, does it depend on the effects of age and menarche?

Aiming to determine the association between joint range of motion (ROM) and muscle strength; and, the effect of age and menarche on those two factors; 132 pre-and post-menarche dancers, aged 12-14 years were assessed for joint ROM and for muscle strength at the hip, knee and ankle and foot joints. En-pointe ROM was significantly correlated with ankle plantar-flexors' (r = -.184) and with ankle dorsiflexors' muscle strength (r = -.221). Hip external rotation ROM was significantly correlated with knee extensors' strength (r = -.263). Pre-menarche dancers had higher joint ROM compared with post-menarche dancers; yet, dancers at post-menarche were stronger compared to dancers at pre-menarche. The slope coefficient was negative at the age of 12 in hip external rotation and in en-pointe (-0.80 and -0.52, respectively) and became steeper with age (age 13: -3.52 and -3.28, respectively; age 14: -6.31 and -4.42, respectively). Along maturation, dancers with high joints ROM showed reduced muscle strength. Pre-menarche dancers have higher joint ROM, yet reduced muscle strength, compared with post-menarche dancers. As the association between joint ROM and muscle strength might be involved with growth and development, young dancers should be screened along pubertal stages in order to decide the correct curricula and to prevent future injuries.

Hip Pain in Ballet Dancers: Evaluation and Management

Hip and groin injuries are common in ballet dancers, who often begin sport-specific training at a young age. The unique demands of ballet include extreme range of motion, with an emphasis on external rotation and abduction. This creates a distinctive constellation of hip symptoms and pathology in this cohort, which may differ from other flexibility sports. When managing hip symptoms in this cohort, orthopaedic surgeons should consider the unique factors associated with ballet, including ballet-specific movements, morphologic adaptations of the hip, and the culture of the sport. Three common etiologies of hip pain in ballet dancers include femoroacetabular impingement syndrome, hip instability, and extra-articular snapping hip syndrome. First-line treatment often consists of focused physical therapy to strengthen the core and periarticular hip musculature, with surgical management reserved for patients who fail to improve with conservative measures.

Understanding hip pathology in ballet dancers

PURPOSE

The literature on hip injuries in ballet dancers was systematically evaluated to answer (1) whether the prevalence of morphological abnormalities and pathology of hip injuries in dancers differs from the general population (2) if there are any specific risk factors which contribute to a higher rate of hip injury and (3) what are the outcomes of primary and secondary intervention strategies.

METHODS

A systematic literature search of Medline, EMBASE and the Cochrane Library was undertaken for all literature relating to hip injuries in ballet dancers using the PRISMA guidelines. Reference lists were also searched for relevant literature. Clinical outcome studies, prospective/retrospective case series published between 1989 and October 2021 were included. Review articles (non-original data), case reports, studies on animals as well as book chapters were excluded.

RESULTS

The search yielded 445 studies, of which 35 were included for final analyses after screening. This included 1655 participants, of which 1131 were females. The analyses revealed that damage at the chondrolabral junction and degenerative disease of the hip may develop at a higher rate in ballet dancers than in the general population (odds ratio > 1 in 15/18 cohorts). The intra-articular lesions were more frequently found in postero-superior region of the hip suggesting an alternative impingement mechanism. Furthermore, numerous risk factors specific for hip injury in ballet were highlighted amidst a wide body of literature which consistently reports risk factors for a more generic 'dancer vulnerability'.

CONCLUSION

Ballet dancers may suffer from both higher rates of chondrolabral damage and degenerative disease in their hips. In contrast to other sports, the intra-articular lesions are more frequently found in postero-superior region of the hip. Future research clarifying the prevalence of osseous abnormalities and prevention strategies in dancers may be pivotal in delaying the development of hip disease in this cohort.

LEVEL OF EVIDENCE

Level IV.

Little or No Differences in Hip Morphology Between Professional Dancers and Controls: A Systematic Review

OBJECTIVE

To systematically evaluate and synthesize the literature on bony hip morphology of professional dancers, as measured by 2D or 3D imaging techniques.

DATA SOURCES

A literature search was performed on November 20, 2020, using MEDLINE, Embase, and Cochrane. Clinical studies were eligible if they reported on hip morphology of professional dancers. Two independent reviewers screened titles, abstracts, and full-texts to determine eligibility; performed data extraction; and assessed the quality of eligible studies according to the Joanna Briggs Institute (JBI) checklist. This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

MAIN RESULTS

The search returned 1384 records; 449 were duplicates, 923 were excluded after title/abstract/full-text screening, and 12 were eligible, reporting on 447 individuals (352 professional dancers and 95 controls). The JBI checklist indicated that 11 studies scored ≥4 points. For professional dancers, lateral center edge angle was 22.4 to 30.8 degrees, acetabular version was 6.7 to 13.5 degrees, neck-shaft angle was 132.5 to 139.5 degrees, and femoral version was 4.7 to 14.4 degrees. Statistically significant differences between dancers and controls were found in some of the studies for acetabular version, neck-shaft angle, and femoral version, although only femoral version showed clinically relevant differences.

CONCLUSIONS

The bony hip morphology of professional dancers is similar to that of other athletes and age-matched controls, which is in contrast to the authors' clinical experience. We presume that the abnormal morphology we have seen at the clinic is only present in symptomatic dancers who require total hip arthroplasty (THA) and is not a general characteristic of all dancers. Further studies should compare the hip morphology of dancers undergoing THA with matched nondancers.

Effect of Integrated Training on Balance and Ankle Reposition Sense in Ballet Dancers

OBJECTIVE

To investigate the effects of a 6-week integrated training program on the ankle joint reposition sense and postural stability in ballet dancers.

METHODS

Sixteen female ballet dancers participated in the study and underwent a 6-week integrated training program consisting of plyometric, proprioception and core stability exercises along with a home program involving additional ankle muscle strengthening and stretching. The ankle joint reposition tests and the parameters of the center of pressure (COP) while performing grand-plie (deep squatting) and releve en demi-pointe (standing on balls of foot) movements were measured before and after training.

RESULTS

After 6 weeks, participants showed significantly smaller absolute ankle joint reposition errors in dorsiflexion (p = 0.031), plantarflexion (p = 0.003) and eversion (p = 0.019) compared to the pre-training measurement. Furthermore, after training, a significantly slower average COP speed at pre-equilibrium during grand-plie movement (p = 0.003) and pre-equilibrium phase of releve en demi-pointe (p = 0.023) were observed. In addition, the maximum COP displacement in the medial-lateral direction was significantly smaller at pre-equilibrium phase during grand-plie (p = 0.044) and releve en demi-pointe movements (p = 0.004) after training.

CONCLUSIONS

The 6-week integrated training program improved the ankle joint reposition sense and postural control in the medial-lateral direction during grand-plie and releve en demi-pointe movements.

Activity Level and Sport Type in Adolescents Correlate with the Development of Cam Morphology

The purpose of this study was to evaluate the influence of the volume and type of sport on the development of cam-type femoroacetabular impingement and acetabular dysplasia.

Generalized joint hypermobility, scoliosis, patellofemoral pain, and physical abilities in young dancers

Background

Many young girls with generalized joint hypermobility (GJH) choose to participate in dance because their bodies are suited for this activity. Scoliosis tends to occur often in thin girls, who also are more likely to choose dance. Both anomalies (GJH and scoliosis) may be related to reduced abilities such as diminished strength and insufficient postural balance, with increased risk for musculoskeletal conditions. The main objectives of the present study were to determine the prevalence of dancers with GJH, the prevalence of dancers with scoliosis, and the prevalence of dancers with these two anomalies; and, to determine differences in physical abilities and the presence of patellofemoral pain (PFP) between young female dancers with and without such anomalies.

Methods

One hundred thirty-two female dancers, aged 12–14 years, were assessed for anthropometric parameters, GJH, scoliosis, knee muscle strength, postural balance, proprioception ability, and PFP.

Results

GJH was identified in 54 dancers (40.9%) and scoliosis in 38 dancers (28.8%). Significant differences were found in the proportion of dancers with no anomalies (74 dancers, 56.1%) and dancers with both anomalies (34 dancers, 25.8%) (p < .001). Dancers with both anomalies had reduced dynamic postural balance in the anterior direction (p = .023), reduced proprioception ability (p < .001), and weaker knee extensors (p = .036) and flexors (p = .040) compared with dancers with no anomalies. Among dancers with both anomalies, 73.5% suffered bilateral PFP, 17.6% suffered unilateral PFP, and 8.8% had no PFP (p < .001).

Conclusions

A high prevalence of young girls participating in dance classes had GJH, as the increased joint flexibility probably provides them with some esthetic advantages. The high prevalence of scoliosis found in these young dancers might be attributed to their relatively low body mass, their delayed maturation, and the selection process of dancers. Dancers with both GJH and scoliosis had decreased muscle strength, reduced postural balance, reduced proprioception, with higher risk of PFP. The main clinical implications are the need to reduce the risk of PFP among dancers by developing appropriate strength and stabilizing exercises combined with proprioceptive and postural balance training, to improve the correct alignment of the hyperextended and hypermobile joints, and to improve their supporting muscle strength.

Analysis of Postural Risk and Pain Assessment in Bharatanatyam Dancers

Background:

Bharatanatyam dance form is an amalgamation of emotion, rhythm, expression, and sculpturesque poses that demand high levels of physical and psychological power during a performance.

Objectives:

To explore musculoskeletal pain and analyze risk factors in Bharatanatyam dancers. The level of injury risk for the “Natyarambham” posture adopted by dancers was also assessed.

Materials and Methods:

A cross-sectional study was conducted in forty female Bharatanatyam dancers who received a minimum of 5 consecutive years of formal dance training from a recognized dance institute. A self-designed questionnaire comprising of demographic profile, dancing characteristics, presence of musculoskeletal pain, and specific area of pain according to the body region was administered. The injury risk of the “Natyarambham” posture was evaluated using a rapid entire body assessment tool (REBA).

Results:

Among 40 female dancers, 75% dancers (n = 30/40, 75% [95% CI 0.61, 0.89] reported pain. The most common site of pain was the low back (n = 22/40, 55% [95% CI 0.39, 0.71]). Using Bonferroni correction for multiple independent comparisons, a significant difference was identified between dancers with and without pain for average performances per year (P = 0.028). As per REBA risk level scoring for Natyarambham posture, 62.5% (n = 25/40, 62.5% [95% CI 0.22, 0.53]) dancers were in the category of high-risk level.

Conclusion:

The findings of this study indicated that the point prevalence of pain in Bharatanatyam dancers is high. Natyarambham posture is considered high risk based on postural assessment.

The Dancer's Hip: The Hyperflexible Athlete: Anatomy and Mean 3-Year Arthroscopic Clinical Outcomes

PURPOSE

To report preoperative anatomy, patient-related outcomes measures, and return to dance rates in a cohort of competitive dancers undergoing an arthroscopic hip procedure.

METHODS

Competitive dancers who underwent an arthroscopic hip procedure between 2008 and 2016 were included. Specific types of dance performed, morphology, and radiographic parameters were documented. Outcomes were evaluated with Modified Harris Hip Score (mHHS), the 12-Item Short Form Health Survey, visual analog scale, and Hip Disability and Osteoarthritis Outcome Scores (HOOS).

RESULTS

There were 63 competitive dancers (77 hips) with a mean age 21.2 years in the current study. Specific types of dance performed included 57 studio dance and 41 high-kick dance, and 28 dancers (44%) were professional-level. Morphology included cam-type femoroacetabular impingement (95%), pincer-type femoroacetabular impingement (40%), anterior inferior iliac spine impingement (subspine) (83%), and mild (borderline) dysplasia (11%). Procedures performed included 95% labral repairs, 5% labral debridements, 99% femoral resections, 49% rim resections, 88% subspine decompressions, and 66% capsular plications. At mean 36 months' follow-up post-arthroscopy, the mean outcome improvements were 25.6 points (mHHS), 18.9 points (HOOS-activities of daily living), 29.9 points (HOOS-Sports), 8.7 points (12-Item Short Form Health Survey), and 3.7 points (visual analog scale) (P < .01 for each). Scores were significantly improved from preoperatively to most recent follow-up for mHHS (60.0 vs 85.6 points), HOOS-activities of daily living (72.5 vs 91.5 points), and HOOS-Sports (49.7 vs 79.6) (P < .01). Sixty-three percent of dancers returned to their previous level of competitive dance, 21% returned to limited or modified dance, and 16% were unable to return to dance, including 1 retirement.

CONCLUSIONS

A careful arthroscopic approach to address cam-type pathomorphology, highly prevalent subspine impingement, and capsular laxity in competitive dancers can achieve a modest rate of return to sport and good-to-excellent patient-reported outcomes at short- to mid-term (3-year) follow-up. Eighty-four percent of dancers ultimately returned to competitive dance, although only 63% returned to their preinjury competitive level.

LEVEL OF EVIDENCE

IV, case series.

Mechanical Demands at the Ankle Joint During Saut de Chat and Temps levé Jumps in Classically Trained Ballet Dancers

Background

During ballet, injuries to the Achilles tendon are associated with the take-off phase of various jumps.

Research question

The purpose of the study was to assess differences in mechanical demand on the body, specifically at the ankle, in two single-leg jumps commonly trained in ballet: a saut de chat (SDC) and a temps levé (TL).

Methods

Fifteen classically trained female dancers had 16 reflective markers placed on the lower body and each dancer performed each jump three times on a force plate. The marker position data and ground reaction forces (GRF) were captured synchronously at 250 Hz and 1000 Hz, respectively. Peak vertical GRF, mean rate of force development (RFD), peak ankle moment, and peak ankle power were determined and averaged across trials. Paired t-tests were used to determine differences between the SDC and the TL.

Results

When compared to the TL, the SDC displayed significantly higher peak vertical GRF (p = 0.003), RFD (p = 0.002), and peak ankle moment and power (p < 0.001). The effect sizes for these differences were large for all variables (Cohen’s d > 0.80).

Conclusion

The mechanical demand at the ankle joint is significantly greater for the SDC than the TL.

Patellofemoral pain, body morphology and alignment in female pubertal dancers: One-year follow-up

The aim of this study was to assess changes in body morphology, anatomical alignment and prevalence of patellofemoral pain (PFP) in young female dancers along one year of pubertal growth, and to identify the risk factors related to PFP in these young dancers. Both legs of 60 dancers were evaluated during grade 7 and again after 1-year. At each of these points in time, the dancers were interviewed concerning their background, and anthropometric measurements, lower-limb physical examinations and knee ultrasound scans were performed. Morphological parameters changed significantly from baseline to follow-up. PFP was found in 53.3% of the dancers' knees at baseline. At follow-up, 55.4% of the asymptomatic knees at baseline developed PFP, and only 9.4% of the symptomatic knees at baseline recovered. Lower BMI was identified among dancers who developed PFP during follow-up compared with dancers with no PFP, either at baseline or at follow-up. A positive grinding and positive Patellar Inhibition Test (PIT) were found to be risk factors for PFP at follow-up. A high prevalence of young dancers suffered PFP, from injuries they sustained mostly during the 1-year of dance practice. Parameters predisposing the dancers to PFP should be identified at early stages of dance class.

The association between menarche, intensity of training and passive joint ROM in young pre-professional female dancers: A longitudinal follow-up study

OBJECTIVES

To determine the association between the status of menarche (yes/no), the intensity of training and the potential to improve passive joint range of motion (ROM) over a 12-month period of dance training.

DESIGN

Prospective cohort study.

SETTING

Dance studio.

PARTICIPANTS

Fifty-nine female dancers aged 12.8 ± 0.5.

MAIN OUTCOME MEASURES

The dancers were asked about their dance intensity and screened for anthropometric parameters and passive joint ROM in Grades 7 and 8.

RESULTS

Along the 12 months of dance training, we found significantly increased ankle-foot en-pointe, hip abduction, and hip external rotation (ER); significantly decreased hip internal rotation (IR); and significant increased hip ER:IR ratio. In Grade 7, 26 dancers (44.1%) reached menarche (Yes menarche); in Grade 8 an additional 23 dancers (39.0%) reached menarche (No/Yes menarche); and 10 dancers (16.9%) had not reached menarche (No menarche). MANOVA (mixed models) with repeated measures to compare joint ROM between the three menarche groups (Yes; No/Yes; No), with h/week dance practice as a co-variant, showed that hip ER, ankle-foot en-pointe, and ER:IR were significantly correlated with h/week in all three menarche groups.

CONCLUSIONS

Most passive joint ROM can be improved over 12 months of dancing around the age onset of menarche. H/week of dance practice is a main factor contributing to improved hip ER, ankle-foot en-pointe and ER/IR ratio.

Ultrasonography and clinical examination of knee injuries in pre- and post- menarche dancers

This study aimed at evaluating whether the prevalence of knee injuries and morphological features are different among pre-and-post menarche dancers; Sixty-seven pre-and-post menarche dancers were screened for anthropometric parameters; knee laxity; patella femoral pain syndrome (PFPS), pathologies and anatomical structure of the knees. Both groups showed a high and similar prevalence of PFPS. The post-menarche dancers produced a significantly higher rate of Tanner stages 3-4 (p = .010), greater weight (p < .001) higher BMI (p = .003); and, higher prevalence of MCL pathology, pes planus, and scoliosis compared with pre-menarche dancers (p < .05). The pre-menarche dancers started dance practice earlier (p = .008); and, showed significantly higher prevalence of lateral laxity, patellar laxity, positive Lachman test and positive Drawer test compared with post-menarche dancers (p < .05). Interactions (menarche yes/no by PFPS no/one leg/both legs) were found for BMI (p = .044; η² = .187), trochlear cartilage thickness (p = .020; η² = 0.121) and tip of patella - trochlear groove distance (p = .024; η² = .150). Pre-and-post-menarche female dancers demonstrated similar prevalence of knee injuries, with different body morphology.

Ultrasonography findings and physical examination outcomes in dancers with and without patellofemoral pain

OBJECTIVES

To identify whether a physical examination for patello-femoral pain (PFP) is related to ultrasonography findings at the knee, and to identify possible factors related to PFP in young dancers.

METHODS

Sixty-seven young female dancers (7th grade, aged 12.8 ± 0.5) from three schools with identical special dance programs were included in the study. All the dancers were interviewed for demographic details, dance background, and training intensity; were evaluated for anthropometric measurements; underwent physical examination of both knees for PFP and for knee range of motion (ROM); and, had ultrasonography assessment for pathologies and of anatomical parts of their knees.

RESULTS

PFP was found in 54.5% of the 134 knees physically examined. In ultrasonography assessment, infra-articular effusion was found in 46.2% of the knees examined. H/week of dance practice was significantly higher among dancers with PFP (in both knees) compared with dancers with no PFP (p < .05). Knees with PFP had a significantly higher prevalence of intra articular effusion (p = .018) and higher prevalence of genu-recurvatum (p = .042). Knees with PFP had significantly greater growth plate width-anterior tibial tuberosity (p = .022) and a greater bony trochlear groove angle (p = .048).

CONCLUSION

This study describes the relationship between physical examination for PFP and the sonographic findings, and the factors related to knee injuries. The results showed a high prevalence of PFP and intra articular knee effusion among young dancers at the age of 12-13 years; and, that the number of hours of practice and anatomical structure are related to PFP. Our results should alert physicians, physiotherapists, athletic trainers and dance teachers to the need for devising modifications of training and injury prevention strategies from a young age (<12 years old).

Métodos usados para avaliar o en dehors ou turnout de dançarinos e bailarinos clássicos: revisão da literatura

RESUMO A técnica do ballet clássico exige a realização máxima do en dehors ou turnout, caracterizado pela rotação externa de membros inferiores. Considerando a sua importância, diversos protocolos para a sua avaliação e mensuração têm sido propostos. O objetivo desta revisão foi investigar sistematicamente quais os métodos utilizados para avaliar o turnout de bailarinos clássicos e/ou praticantes de ballet clássico existentes atualmente. A busca foi feita nas bases de dados Scopus, Science Direct e PubMed, no mês de fevereiro de 2016, e os artigos encontrados deveriam: estar redigidos na língua inglesa, avaliar bailarinos clássicos ou dançarinos que praticassem ballet clássico e mensurar o en dehors ou turnout. Foram encontrados 593 artigos, dos quais 25 foram pré-selecionados para esta revisão, apresentando quinze diferentes métodos e instrumentos de mensuração do turnout: cinemetria; inclinômetro; turnout protactor ou transferidor para medir o turnout; goniômetro; Dupuis Tropometer; transferidor original; fotos dos sujeitos; discos rotacionais; teste de flexibilidade de Nicholas; flexímetro; desenho clínico dos pés; sujeito sobre um pedaço de papel ou solo ou quadro branco; ressonância magnética; filmagem do sujeito executando sequência de passos; Dasco Pro Angle Finder. Esta revisão apresenta forte evidência para afirmar que não há, até o presente momento, um método ou instrumento padrão-ouro para mensuração do turnout de bailarinos, de modo que esta costuma ser adaptada e escolhida de acordo com o objetivo de cada estudo.

Bony Morphology of Femoroacetabular Impingement in Young Female Dancers and Single-Sport Athletes

BACKGROUND

Femoroacetabular impingement (FAI) is a painful and limiting condition of the hip that is often seen in young athletes. Previous studies have reported a higher prevalence of this disorder in male athletes, but data on the structural morphology of adolescent and young adult female athletes, specifically those involved in dance, are lacking.

PURPOSE

(1) To investigate the radiographic morphology of FAI deformities in adolescent and young adult female single-sport dance and nondance athletes and (2) to examine the differences in the radiographic findings between these 2 groups.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A retrospective chart review of 56 female single-sport athletes 10 to 21 years of age with a diagnosis of FAI within a single-sports medicine division of a pediatric academic medical center was performed. Acetabular index (AI), lateral center-edge angle (LCEA), crossover sign, and ischial spine sign were measured bilaterally on anteroposterior radiographs; alpha angle (AA) was measured on lateral films, and anterior center-edge angle (ACEA) was measured on false-profile films. Independent t tests and Mann-Whitney U tests were used to compare mean angle measurements between dance and nondance athletes. Dichotomized categorical variables and crossover and ischial spine signs were analyzed between dance and nondance athletes by applying a chi-square test. Statistical significance was set as P < .05 a priori.

RESULTS

Significant differences in angle measurements were noted. AA was significantly lower in the dancers compared with the nondance athlete group (49.5° ± 6.0° vs 53.9° ± 7.3°, P = .001). The LCEA and ACEA of dance athletes were significantly greater compared with nondance athletes (33.8° ± 6.7° vs 30.9° ± 5.8° [P = .016] and 36.0° ± 8.1° vs 32.3° ± 7.0° [P = .035], respectively). No significant difference in AI was seen between the 2 cohorts (5.0° ± 4.0° for dancers vs 5.9° ± 3.4° for nondancers, P = .195).

CONCLUSION

Significant differences existed in the radiographic bony morphology of young female single-sport dance athletes compared with nondance athletes with FAI. In dance athletes, symptoms were seen in the setting of normal bony morphology.

Lower extremity and spine characteristics in young dancers with and without patellofemoral pain

Very little is known about patellofemoral pain syndrome (PPFS) among young dancers. Understanding the mechanism of the injury and implementing a preventative programme are important in order to minimize the risk of PFPS. The aim of the current study is to determine the extent to which factors such as lower extremity and back characteristics are common among dancers with PFPS. The study population included 271 dancers with PFPS and 271 non-injured dancers, aged 10-16 years. All dancers were screened for morphometric profile, dance discipline (h/week), anatomical anomalies (present/absent of scoliosis, genu valgus/varum, etc.), and joint range of motion (measured by goniometer at the hip, knee, ankle, foot, and spinal joints). The predicting factors for PFPS among young dancers (10-11 years old) were: hyper hip abduction (OR = 0.906) and lower back and hamstring flexibility (OR = 3.542); for adolescent dancers (12-14 years old): hyper ankle dorsiflexion (OR = 0.888), hind foot-varum (OR = 0.260), and mobility of patella (OR = 2.666); and, for pre-mature dancers (15-16 years old): scoliosis (OR = 5.209), limited ankle plantar-flexion (OR = 1.060), and limited hip internal rotation (OR = 1.063). In conclusion, extrinsic and intrinsic parameters predisposing the dancers to knee injuries should be identified by screening in early stages of dance classes.

Sex and growth effect on pediatric hip injuries presenting to sports medicine clinic

To compare sports-related hip injuries on the basis of sex and age in a cohort of young athletes. A 5% random probability sample of all new patients' charts over a 10-year time period was selected for investigation. The most common hip injury diagnoses, sport at time of injury, mechanism (acute/traumatic vs. overuse), and types (bony vs. soft tissue) were compared by sex and age (preadolescent vs. adolescent). Descriptive and χ-analyses were carried out. The interaction of sex and age with respect to hip injury over time was examined by two-way (sex, age) analysis of variance. A total of 2133 charts were reviewed; N=87 hip injuries. The main diagnoses for males included labral tear (23.1%), avulsion fracture (11.5%), slipped capital femoral epiphysis (11.5%), dislocation (7.7%), and tendonitis (7.7%). The main diagnoses for females were labral tear (59.0%), tendonitis (14.8%), snapping hip syndrome (6.6%), strain (4.9%), and bursitis (4.9%). The five most common sports/activities at the time of hip injury were dancing/ballet (23.0%), soccer (18.4%), gymnastics (9.2%), ice hockey (8.1%), and track and field (6.9%). Age by sex comparisons showed a greater proportion of the total hip injuries (38.5%) in males compared with females (8.2%) during preadolescence (5-12 years). However, in adolescence (13-17 years), the hip injury proportion was significantly higher in females (91.8%) compared with males (61.5%; P<0.001). Injury mechanism and type differed by sex, with females sustaining more chronic/overuse (95.1%) and soft tissue type injuries (93.4%) compared with males (50.0 and 53.8%, respectively; P<0.001). Females were found to have a sharper increase in hip injury proportion as they progressed through puberty compared with males (analysis of variance sex-by-age interaction; P<0.001). Hip injury mechanism and type differed significantly between males and females during growth. Notably, the proportion of hip injuries in the young female athletes showed a significantly greater increase with advancing age compared with males. Hip injuries in children and the interplay with growth, as it relates to injury predisposition, require further investigation to facilitate efforts aimed at prevention.

LEVEL OF EVIDENCE III

Cross-sectional epidemiological study.

The Hyperflexible Hip: Managing Hip Pain in the Dancer and Gymnast

Context:

Dance, gymnastics, figure skating, and competitive cheerleading require a high degree of hip range of motion. Athletes who participate in these sports use their hips in a mechanically complex manner.

Evidence Acquisition:

A search of the entire PubMed database (through December 2013) and additional searches of the reference lists of pertinent articles.

Study Design:

Systematic review.

Level of Evidence:

Level 3.

Results:

Whether innate or acquired, dancers and gymnasts have some hypermobility that allows their hips to be placed in potentially impinging or unstable positions required for their given activity. Such extremes of motion can result in both intra-articular and extra-articular impingement as well as compensatory osseous and muscular pathology. In addition, dancers and gymnasts are susceptible to impingement-induced instability. Dancers with innate generalized hyperlaxity are at increased risk of injury because of their activities and may require longer recovery times to return to play. Both nonoperative and operative treatments (arthroscopic and open) have an important role in returning flexibility athletes to their preoperative levels of sport and dance.

Conclusion:

Because of the extreme hip motion required and the compensatory soft tissue laxity in dancers and gymnasts, these athletes may develop instability, impingement, or combinations of both. This frequently occurs in the setting of subtle pathoanatomy or in patients with normal bony anatomy. With appropriate surgical indications and the correct operative technique, the treating surgeon can anticipate high levels of return to play for the gymnast and dancer with hip pain.

Three-dimensional analysis of a ballet dancer with ischial tuberosity apophysitis. A case study

The purpose of this case study was to describe the three-dimensional biomechanics of common ballet exercises in a ballet dancer with ischial tuberosity apophysitis. This was achieved by comparing kinematics between the symptomatic (i.e. ischial apophyseal symptoms) and contralateral lower limbs, as well as via reported pain. Results suggest consistent differences in movement patterns in this dancer. These differences included: 1) decreased external rotation of contralateral hip, hence a decreased hip contribution to 'turn out'; 2) increased contralateral knee adduction and internal rotation; 3) an apparent synchronicity in the contralateral lower limb of the decreased hip external rotation and increased knee adduction; and 4) minimal use of ankle plantar/dorsiflexion movement for symptomatic side. Pain related to the left ischial apophysitis was associated with reduced amplitudes especially in fast ballet movements that required large range of motion in flexion and adduction in the left hip joint. These findings suggest that ischial apophysitis may limit dancer's ballet technique and performance. Key PointsThe pain related to the left ischial apophysitis was associated with reduced amplitudes especially in fast ballet movements that require large range of motion. This may affect to the lower limbs kinematics, and limit dancer's technique and performance.Compensatory strategies in the kinetic chain, differences in the joint angles between the lower limbs, traction forces, velocity and amplitude demands should be taken in consideration while training and rehabilitation of the ischial apophyseal injury within classical ballet.

Effect of Mulligan's and Kinesio knee taping on adolescent ballet dancers knee and hip biomechanics during landing

Taping is often used to manage the high rate of knee injuries in ballet dancers; however, little is known about the effect of taping on lower-limb biomechanics during ballet landings in the turnout position. This study investigated the effects of Kinesiotape (KT), Mulligan's tape (MT) and no tape (NT) on knee and hip kinetics during landing in three turnout positions. The effect of taping on the esthetic execution of ballet jumps was also assessed. Eighteen pain-free 12-15-year-old female ballet dancers performed ballet jumps in three turnout positions, under the three knee taping conditions. A Vicon Motion Analysis system (Vicon Oxford, Oxford, UK) and Advanced Mechanical Technology, Inc. (Watertown, Massa chusetts, USA) force plate collected lower-limb mechanics. The results demonstrated that MT significantly reduced peak posterior knee shear forces (P = 0.025) and peak posterior (P = 0.005), medial (P = 0.022) and lateral (P = 0.014) hip shear forces compared with NT when landing in first position. KT had no effect on knee or hip forces. No significant differences existed between taping conditions in all landing positions for the esthetic measures. MT was able to reduce knee and the hip forces without affecting the esthetic performance of ballet jumps, which may have implications for preventing and managing knee injuries in ballet dancers.

The demographic characteristics of high-level and recreational athletes undergoing hip arthroscopy for femoroacetabular impingement: a sports-specific analysis

PURPOSE

The purpose of this study was to determine differences in age, gender, and the need for bilateral surgery between high-level athletes grouped by sports with similar mechanical demands on the hip and recreational athletes undergoing hip arthroscopy for femoroacetabular impingement (FAI).

METHODS

By use of a hip-preservation center registry, a retrospective review of patients undergoing hip arthroscopy for FAI between March 2010 and April 2012 was performed. Athletes were categorized as high level (high school, collegiate, or professional) or recreational. We performed a subgroup analysis for high-level athletes, looking at differences among contact, cutting, impingement, overhead/asymmetric, endurance, and flexibility sports.

RESULTS

The study included 288 high-level athletes and 334 recreational athletes. Being a high-level athlete was associated with a younger age (mean age, 20.2 years v 33.0 years; odds ratio, 0.69; P < .001) and male gender (61.5% v 53.6%; odds ratio, 1.75; P = .03). The percentage of high-level athletes undergoing bilateral surgery was higher than that of recreational athletes (28.4% v 15.9%); however, this association was found to be confounded by age on multivariate analysis. The most common sports for high-level athletes were soccer, hockey, and football. Athletes participating in cutting sports were significantly younger than athletes participating flexibility, contact, or impingement sports.

CONCLUSIONS

When compared with recreational athletes undergoing arthroscopic treatment for FAI, high-level athletes are more likely to be younger, to be male, and to undergo bilateral surgery. When high-level athletes are grouped by the mechanical demands placed on the hip by their sport, athletes participating in cutting sports are more likely to be younger than those in the other groups.

LEVEL OF EVIDENCE

Level IV, case series.

Influence of ankle injury on muscle activation and postural control during ballet grand plié

Ballet deep squat with legs rotated externally (grand plié) is a fundamental movement for dancers. However, performing this task is a challenge to ankle control, particularly for those with ankle injury. Thus, the purpose of this study was to investigate how ankle sprains affect the ability of postural and muscular control during grand plié in ballet dancers. Thirteen injured dancers and 20 uninjured dancers performed a 15 second grand plié consisting of lowering, squatting, and rising phases. The lower extremity motion patterns and muscle activities, pelvic orientation, and center of pressure (COP) excursion were measured. In addition, a principal component analysis was applied to analyze waveforms of muscle activity in bilateral medial gastrocnemius, peroneus longus, and tibialis anterior. Our findings showed that the injured dancers had smaller pelvic motions and COP excursions, greater maximum angles of knee flexion and ankle dorsiflexion as well as different temporal activation patterns of the medial gastrocnemius and tibialis anterior. These findings suggested that the injured dancers coped with postural challenges by changing lower extremity motions and temporal muscle activation patterns.

Influence of turnout on foot posture and its relationship to overuse musculoskeletal injury in professional contemporary dancers: a preliminary investigation

BACKGROUND

The angle of turnout is thought to predispose professional dancers to overuse musculoskeletal injuries of the lower limb; yet, the influence of angle of turnout on foot posture is currently unknown.

METHODS

Twelve professional contemporary dancers (five women and seven men; mean age, 26.8 years) were recruited. The angle of gait and angle of turnout were measured using a quasi-static clinical tracing method. Foot posture was assessed in the base of gait and angle of turnout using the Foot Posture Index. Each dancer completed a dance history and injury questionnaire.

RESULTS

The results show a tendency toward a pronated foot posture (mean, 9°) in the angle of turnout position. A significant relationship was noted between the Foot Posture Index and angle of turnout (ρ = 0.933-0.968, P < .01) and between the number of reported injuries and change in foot posture in the angle of turnout (ρ = 0.789, P < .01) (right foot only). Twenty-eight injuries were reported; male dancers experienced a mean of 2.8 injuries and females a mean of 1.6 injuries. An inverse relationship was noted between age at training initiation and total reported injuries (r =-0.867, P < .01). All of the dancers reported a history of injury to the spine or lower limb, and 9 of the 12 reported an injury within the previous 12 months.

CONCLUSIONS

Turnout is one of the most fundamental aspects of dance technique. This study suggests a trend toward pronation in angle of turnout and a link to lower-limb musculoskeletal injury.

Correlation of clinical and magnetic resonance imaging findings in hips of elite female ballet dancers

PURPOSE

To understand why professional female ballet dancers often complain of inguinal pain and experience early hip osteoarthritis (OA). Goals were to examine clinical and advanced imaging findings in the hips of dancers compared with those in a matched cohort of nondancers and to assess the femoral head translation in the forward split position using magnetic resonance imaging (MRI).

METHODS

Twenty professional female ballet dancers and 14 active healthy female individuals matched for age (control group) completed a questionnaire on hip pain and underwent hip examination with impingement tests and measurement of passive hip range of motion (ROM). All had a pelvic 1.5 T MRI in the back-lying position to assess femoroacetabular morphologic features and lesions. For the dancers, additional MR images were acquired in the split position to evaluate femoroacetabular congruency.

RESULTS

Twelve of 20 dancers complained of groin pain only while dancing; controls were asymptomatic. Dancers' passive hip ROM was normal. No differences in α neck angle, acetabular depth, acetabular version, and femoral neck anteversion were found between dancers and controls. MRI of dancers while performing splits showed a mean femoral head subluxation of 2.05 mm. MRI of dancers' hips showed labral tears, cartilage thinning, and herniation pits, located in superior and posterosuperior positions. Lesions were the same for symptomatic and asymptomatic dancers. Controls had proportionally the same number of labral lesions but in an anterosuperior position. They also had 2 to 3 times fewer cartilage lesions and pits than did dancers.

CONCLUSIONS

The results of our study are consistent with our hypothesis that repetitive extreme movements can cause femoral head subluxations and femoroacetabular abutments in female ballet dancers with normal hip morphologic features, which could result in early OA. Pathologic changes seen on MRI were symptomatic in less than two thirds of the dancers.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Ballet injuries: injury incidence and severity over 1 year

STUDY DESIGN

Prospective, descriptive single-cohort study.

OBJECTIVE

To assess the incidence and severity of injuries to a professional ballet company over 1 year.

METHODS

Data for an elite-level ballet company of 52 professional dancers were collected by an in-house medical team using a time-loss injury definition.

RESULTS

A total of 355 injuries were recorded, with an overall injury incidence of 4.4 injuries per 1000 hours (female, 4.1; male, 4.8; P>.05) and a mean of 6.8 injuries per dancer (female, 6.3; male, 7.3; P>.05). Mean injury severity was 7 days (female, 4; male, 9; P<.05). Most injuries were classified as overuse (64%; female, 68%; male, 60%; P>.05); mean severity of injury was 3 days for females and 9 days for males (P<.05). The percentage of traumatic injuries was 32% for females and 40% for males (P<.05); the corresponding severity was 6 and 10 days, respectively (P<.05).

CONCLUSION

The relatively high number of injuries reported and the resulting loss of dance time support the need to introduce interventions to reduce the risk of injury in professional dancers.J Orthop Sports Phys Ther 2012;42(9):781-790. Epub 19 July 2012. doi:10.2519/jospt.2012.3893.

Hip dysplasia and the performing arts: is there a correlation?

Dancers frequently present with hip pain. The etiology of this pathology has not been clearly identified from an anatomical perspective. Structural variations including hip dysplasia and dynamic variables from the foot to the pelvis will be discussed. Understanding the etiology as a structural entity, neuromuscular entity or a combination of the two, allows for a successful rehabilitative process and a successful return to dance. This article describes the possible correlation between hip dysplasia and hip pain in the dancer, the relationship of dance postures to the kinematic chain and outlines possible treatment strategies for management.

Paratenonitis of the foot and ankle in young female dancers

BACKGROUND

In their pursuit of excellence, dancers continually face the risk of injuries, such as paratenonitis. This attests to the strong need for preventive action, which is possible only if major risk factors are identified. The aim of the present descriptive study was to determine the association between risk factors and paratenonitis in young recreational female dancers.

METHODS

One thousand eighty-two non-professional female dancers, aged 8 to 16 years, were screened. The risk factors considered for paratenonitis were: joint range of motion (ROM), body structure, anatomic anomalies, dance technique, and dance discipline. All dancers were clinically examined for current ankle/foot paratenonitis.

RESULTS

Ninety-three dancers (8.6%) manifested a paratenonitis at the ankle or foot joints. ROM such as hyper ankle plantarflexion and hyper hip external rotation, false dance technique, and hours of practice per week were found to be associated with increased rate of injury. Regression analysis indicated that dancers with paratenonitis had greater hip external rotation ROM compared to dancers without paratenonitis. No association with injury was found with age of onset of menarche, body structure, and anatomic anomalies such as scoliosis.

CONCLUSION

Precautionary steps, such as screening for joint ROM and dance technique, may reduce the risk of dance injury. Furthermore, our results led to a very significant justification of the dance maxim ``don't force your natural joint ROM and especially your `turnout' position,'' as it could increase your chance to develop paratenonitis.

Sports-related injuries in the young female athlete

The number of females participating in sports continues to increase. Adolescent and preadolescent females are at a risk injury to both their open growth plates as well as their joints. The purpose of this article is to review the common injuries seen with the most popular sports with females. Mt Sinai J Med 77:307-314, 2010. (c) 2010 Mount Sinai School of Medicine.

Injury patterns in elite preprofessional ballet dancers and the utility of screening programs to identify risk characteristics

STUDY DESIGN

Retrospective descriptive cohort study.

OBJECTIVES

To describe the distribution and rate of injuries in elite adolescent ballet dancers, and to examine the utility of screening data to distinguish between injured and noninjured dancers.

BACKGROUND

Adolescent dancers account for most ballet injuries. Limited information exists, however, regarding the distribution of, rate of, and risk factors for, adolescent dance injuries.

METHODS AND MEASURES

Two hundred four dancers (age, 9-20 years) were screened over 5 years. Screening data were collected at the beginning and injury data were collected at the end of each training year. Descriptive statistics were used to characterize distribution and rate of injuries. Inference statistics were used to examine differences between injured and noninjured dancers.

RESULTS

Fifty-three percent of injuries occurred in the foot/ankle, 21.6% in the hip, 16.1% in the knee, and 9.4% in the back. Thirty-two to fifty-one percent of the dancers were injured each year, and, over the 5 years, there were 1.09 injuries per 1000 athletic exposures, and 0.77 injuries per 1000 hours of dance. Significant differences between injured and noninjured dancers were limited to current disability scores (P = .007), history of low back pain (P = .017), right foot pronation (P = .005), insufficient right-ankle plantar flexion (P = .037), and lower extremity strength (P = .045).

CONCLUSION

Distribution of injuries was similar to that of other studies. Injury rates were lower than most reported rates, except when expressed per 1000 hours of dance. Few differences were found between injured and noninjured dancers. These findings should be considered when designing and implementing screening programs.