A new consideration in athletic injuries. The classical ballet dancer

Excessive Knee Internal Rotation during Grand Plié in Classical Ballet Female Dancers

Classical ballet dancers are exposed daily to physically demanding movements. Among these, the Grand Plié stands out for its biomechanical complexity, particularly the stress applied to the knee joint. This study investigates the knee kinematics of healthy professional classical ballet dancers performing the Grand Plié. Twenty dancers were evaluated with a motion analysis system using a marker-based protocol. Before measurements, the self-reported Global Knee Functional Assessment Scale was delivered for the knees' functional ability, and the passive range of knee motion was also assessed. The average score on the Global Knee Functional Assessment Scale was 94.65 ± 5.92. During a complete circle of the Grand Plié movement, executed from the upright position, the average maximum internal rotation of the knee joint was 30.28° ± 6.16°, with a simultaneous knee flexion of 134.98° ± 4.62°. This internal rotation observed during knee flexion exceeds the typical range of motion for the joint, suggesting a potential risk for knee injuries, such as meniscal tears. The findings provide an opportunity for future kinematic analysis research, focusing on the movement of the Grand Plié and other common ballet maneuvers. These data have the potential to yield valuable information about the knee kinematics concerning meniscus damage.

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.

Negative magnetic resonance imaging in three cases of anterior tibial cortex stress fractures

Anterior mid-tibial cortex stress fractures (ATCSF) are uncommon and notoriously challenging to treat. They are termed high risk due to their predilection to prolonged recovery, nonunion and complete fracture. Early diagnosis is essential to avoid progression and reduce fracture complications. Imaging plays a key role in confirming the diagnosis. Magnetic resonance imaging (MRI) is accepted as the gold standard modality due to its high accuracy and nonionizing properties. This report describes three cases of ATCSFs in recreational athletes who had positive radiographic findings with no significant MRI changes. Two athletes had multiple striations within their tibias. Despite the radiographic findings, their severity of symptoms were low with mild or no tenderness on examination. Clinicians should be mindful that the ATCSFs may not present with typical acute stress fracture symptoms. We recommend that plain radiographs should be used as the first line investigation when suspecting ATCSFs. Clinicians should be aware that despite MRI being considered the gold standard imaging modality, we report three cases where the MRI was unremarkable, whilst radiographs and computed tomography confirmed the diagnosis. We urge clinicians to continue to use radiographs as the first line imaging modality for ATCSFs and not to directly rely on MRI. Those who opt directly for MRI may be falsely reassured causing a delay in diagnosis.

Factors related to prevalence of hallux valgus in female university students: a cross-sectional study

Background

We investigated the prevalence of hallux valgus (HV) and examined its association with various factors in a cross-sectional study of Japanese female university students.

Methods

A questionnaire survey of foot symptoms, lifestyle, and body mass index (BMI) was administered to 343 women who provided informed consent at a women’s university. Footprints were obtained and bone density was measured. Associations of HV with various factors were analyzed by logistic regression analysis.

Results

Big toe pain was reported in 26.5% of the women. HV (HV angle, ≥15°) was present in the left foot in 22.4%, the right foot in 20.7%, and unilaterally or bilaterally in 29.7% of women. Mild HV (HV angle, ≥15° to <20°) was noted in the left foot and right foot in 13.4% and 13.1% of women, respectively; no severe HV (HV angle, ≥40°) was observed. HV was associated with big toe pain (adjusted OR: 3.56, 95% CI: 2.01–6.32), history of HV in the mother or maternal grandmother (adjusted OR: 2.45, 95% CI: 1.19–5.02), and history of HV in other family members (adjusted OR: 3.09, 95% CI: 1.35–7.06). Moderate HV was associated with big toe pain (adjusted OR: 4.58, 95% CI: 2.17–9.66) and history of HV in the mother or maternal grandmother (adjusted OR: 3.36, 95% CI: 1.40–8.07). The proportion of women with big toe pain increased significantly with HV severity.

Conclusions

HV was present in about 30% of female university students. Young women with big toe pain or a family history of HV should be evaluated for HV.

Chronic inflammation and neutrophil activation as possible causes of joint diseases in ballet dancers

Herein, we investigated the effects of a ballet class on the kinetic profiles of creatine kinase (CK) and lactate dehydrogenase (LDH) activities, cytokines, complement component 3 (C3), and the concentrations of immunoglobulin (Ig), IgA and IgM, in ballerinas. We also verified neutrophil death and ROS release. Blood samples were taken from 13 dancers before, immediately after, and 18 hours after a ballet class. The ballet class increased the plasma activities of CK-total (2.0-fold) immediately after class, while the activities of CK-cardiac muscle (1.0-fold) and LDH (3.0-fold) were observed to increase 18 hours after the class. Levels of the TNF-α, IL-1β, IgG, and IgA were not affected under the study conditions. The exercise was found to induce neutrophil apoptosis (6.0-fold) 18 hours after the ballet class. Additionally, immediately after the ballet class, the neutrophils from the ballerinas were found to be less responsive to PMA stimulus. Conclusion. Ballet class was found to result in inflammation in dancers. The inflammation caused by the ballet class remained for 18 hours after the exercise. These findings are important in preventing the development of chronic lesions that are commonly observed in dancers, such as those with arthritis and synovitis.

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.

Dance-Related Injury

Although dance medicine has derived extensive knowledge from sports medicine, some aspects covered in the practice of dance medicine are unique to this field. Acute and overuse injuries must be analyzed within the scope of associated mechanisms of injury, mainly related to the practice of specific dance techniques. Even though most available medical literature concerning dance medicine is specific to ballet-related conditions, many of the concepts covered here and in other articles can be helpful in the treatment and diagnosis of participants in other dance disciplines. Continued research is expanding the knowledge on injury patterns of different dance disciplines. It is the experience of dance practitioners that dancers are quite in touch with their bodies; thus, when their ailments are systematically analyzed, and underlying cause can usually be identified. In this sense, it is evident that the principles of dance medicine and rehabilitation allow the practitioner to arrive at a diagnosis and treat the underlying causes to prevent reinjury, ameliorate sequelae from injury, and minimize residual deficits after injury.

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

OBJECTIVE

To examine in a cross sectional study the influence of femoral torsion (FT) and passive hip external rotation (PER) on turnout (TO). Starting age, years of classical ballet training, and current and past dance training intensity were assessed to determine their influence on FT, PER, and TO in pre-professional female dancers.

METHODS

Sixty four dancers (mean (SD) age 18.16 (1.80) years) were recruited from four different dance training programmes. They completed a dance history questionnaire. FT was measured using a clinical method. PER was measured with the subjects prone, and TO was measured with the subjects standing.

RESULTS

Mean TO was 136 degrees, mean unilateral PER was 49.4 degrees, and mean FT was 18.4 degrees. A positive correlation was observed between PER combined (PERC) and TO (r = 0.443, p < 0.001). A negative association was found between FT combined (FTC) and PERC (r = -0.402, p = 0.001). No association was found between starting age or years of classical ballet training and FTC, PERC, or TO. Dancers who trained for six hours a week or more during the 11-14 year age range had less FT than those who trained less (mean difference 6 degrees, 95% confidence interval 1.4 to 10.3). Students currently training for longer had higher levels of TO (p < 0.001) but comparable PERC and FTC.

CONCLUSION

FT is significantly associated with PERC. Dancers who trained for six hours a week or more at 11-14 years of age had significantly less FT. FTC had a significant influence on PERC, but no influence on the execution of TO.

Range of joint movement in female dancers and nondancers aged 8 to 16 years: anatomical and clinical implications

BACKGROUND

Little data are available on changes that occur with age in joint range of motion in dancers and nondancers.

HYPOTHESIS

In dancers, joint range of motion will increase with age, whereas it will decrease in nondancers, independent of the joint studied.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

The study population included 1320 female dancers, aged 8 to 16 years, who participated in different types of dancing classes (classical ballet, modern dance, jazz, etc) and 226 nondancers of similar age. Range of motion was measured for the hip, knee, ankle, foot, and spinal joints.

RESULTS

The pattern of differences in range of motion with age varied in different joints and types of movement. (1) For combined ankle and foot plantar flexion (pointe), ankle plantar flexion, and hip external rotation, there was no change in range of motion in dancers, whereas range of motion diminished with age in the nondancers. (2) For ankle dorsiflexion, neither group showed any change with age, and range of motion was significantly greater in the nondancer group. (3) For knee flexion, hip flexion, and hip internal rotation, range of motion decreased with age in both groups. (4) For hip abduction, range of motion decreased with age in dancers and remained constant in the nondancers. (5) For hip extension, range of motion increased in both groups. (6) For lower back and hamstrings, range of motion increased among dancers with age and remained constant among nondancers.

CONCLUSION

Dancers and teachers should realize that passive joint range of motion is unlikely to improve with age. Therefore, the major goal of a dancing program should focus on exercises that retain the natural flexibility of the dancers' joints rather than trying to improve them.

Ballet dancer's turnout and its relationship to self-reported injury

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To compare the relationship between the degrees of turnout, passive hip external rotation range of motion, and self-reported history of low back and lower extremity injury in ballet dancers.

BACKGROUND

Ballet dancers are encouraged to externally rotate their lower extremities (turnout) as far as possible. This may cause stress on the dancers' low back and lower extremities, putting them at risk for injury.

METHODS AND MEASURES

Thirty college-level ballet dancers and instructors were evaluated. Each participant completed an injury questionnaire that placed the participant either in a group with a self-reported history of low back and lower extremity injury or in a group without a self-reported history of low back and lower extremity injury. Each dancer's first-position turnout and passive external rotation range of motion for both hips were measured. The comparison between each dancer's first-position turnout and the measured hip external rotation range of motion was called "compensated turnout." A 2-sample test was used to determine if the average compensated turnout was significantly different in the injured and noninjured groups.

RESULTS

The mean (+/- SD) compensated turnout values for the injured and noninjured groups were 25.40 degrees (+/- 21.3 degrees) and 4.7 degrees (+/- 16.3 degrees), respectively. This difference was significant at P = 0.006.

CONCLUSION

Based on a self-reported history of low back and lower extremity injuries, ballet dancers have a greater risk of injury if they reach a turnout position that is greater than their available bilateral passive hip external rotation range of motion.

Pedobarographic and musculoskeletal examination of collegiate dancers in relevé

Twenty-one collegiate ballet pupils were evaluated via history/questionnaire, musculoskeletal assessment, and pedobarographs, focusing on factors (e.g., alignment of hip, knee, and foot) thought to affect the important and common second-position relevé in dance. In a blinded manner, three observers classified the pedobarographs (obtained by an independent examiner) according to force distribution through the foot. Most dancers bore weight through the toes and transmitted force on both the medial and central metatarsal heads, and some transmitted force through only one of these rays, but none transmitted force through the lateral ray alone. This analysis provides a baseline for future assessment of normal or abnormal dance maneuvers.

Flexor hallucis longus dysfunction: an overview

Whereas acute and chronic injuries of the tibialis posterior, peroneal and Achilles tendon are frequently encountered, disorders of the flexor hallucis longus tendon are often overlooked, which may contribute to chronic pain and disability. Patients with stenosing tenosynovitis of the flexor hallucis longus tendon frequently present with overlapping signs and symptoms of flexor hallucis longus tendinitis, plantar fasciitis and tarsal tunnel syndrome, which the authors collectively refer to as "flexor hallucis longus dysfunction." A keen awareness of the presenting signs and symptoms and use of ancillary MR imaging and FHL tenography will assist the practitioner in recognizing this commonly misdiagnosed condition.

Delayed union stress fractures of the anterior tibia: conservative management

INTRODUCTION

A conservative method of treating four delayed union stress fractures of the anterior mid-tibia is described, with an illustrative case history.

METHODS

Once diagnosed each of the patients was treated in a pneumatic lower leg brace with modified rest. The mean (range) age of the patients was 28 (24-32) years and all were involved in professional or amateur sports. The mean (range) duration of symptoms before diagnosis and definitive treatment of the four fractures was 9 (3-14) months.

RESULTS

Use of this technique avoided the need for surgery in this group of patients and allowed return to unrestricted activity an average of 12 months from presentation.

CONCLUSION

The treatment is cost effective and avoids the often uncertain results and morbidity associated with surgery for these difficult stress fractures.

Lesões na dança: estudo transversal híbrido em academias da cidade de Bauru-SP

As atividades físicas praticadas pelos bailarinos predispõem-nos à ocorrência de inúmeros agravos. A busca por informações sobre as lesões dessa modalidade permitiu constatar, em nosso meio, escassez de investigações sobre o assunto. Nesse sentido, o objetivo desta pesquisa foi apontar as principais lesões da dança, visando descrever sua distribuição e caracterização a partir de nossa realidade, bem como sugerir medidas preventivas para os agravos de maior ocorrência. Para tanto, realizou-se estudo com 122 bailarinas na faixa etária de 8 a 30 anos, alocadas nas academias de dança da cidade de Bauru. Em sua maioria, eram membros do corpo de baile (42%) ou estudantes (45%), com 3 a 11 anos de prática (73%), alunas de balé clássico (84%) e jazz (66%) e participavam de 4 a 8 aulas semanais (70%), com duração de 60 a 120 minutos (89%). O procedimento para coleta de dados foi o inquérito de morbidade referida para obtenção de informações sobre os agravos ocorridos no período de um ano. A apresentação dos resultados deu-se sob a forma de estatística descritiva, com distribuições de freqüência absoluta, relativa, corrigida e razão de lesões. Em termos analíticos foram utilizados testes não paramétricos de Wilcoxon, Spearman e Kruskal-Wallis, para p < 0,05. Os resultados apontaram 53,27% das respondentes com freqüências entre 1 e 6 lesões agudas, que aumentam com a idade, concentram-se no plano tegumentar (79,46%) e estão associadas a variáveis como a idade em que começou a dançar e com o uso de sapatilha de ponta; 97,48% são agravos de membros inferiores, com predominância de calos (47,03%) e bolhas (28,56%) nos pés. O balé clássico foi o estilo responsável pela maior parte das lesões; as mais experientes e as estudantes foram as mais afetadas e o uso da sapatilha de ponta implicou risco elevado para ocorrência dos agravos observados nos pés.

Relationship between hip external rotation and turnout angle for the five classical ballet positions

Functional turnout for each of the five classical ballet positions involves lower extremity motion that occurs primarily through hip external rotation. Ballet dancers often attempt to increase turnout angle through excessive motions at the foot or knee that may be associated with the development of musculoskeletal pathology. The purpose of this study was to further the understanding of turnout by identifying the relationship between available hip external rotation an functional turnout for the five classical ballet positions. Subjects were 20 female ballet dancers between the ages of 11 and 14. The investigators measured hip external rotation as the sum of passive external rotation available at both hips of each subject. Functional turnout angle was measured for each subject as the subject stood in each of the five classical ballet positions. A repeated measures analysis of variance and Tukey Honestly Significant Difference test indicated that hip external rotation was significantly less than functional turnout for the five classical ballet positions. No significant differences in functional turnout angle were present among the five ballet functional turnout angle for each of the five ballet positions. Hip external rotation should not be used to predict functional turnout for the five classical ballet positions. Turnout in first position may be useful as guide for functional turnout for the crossed foot positions: third, fourth, and fifth.

Flexor hallucis longus dysfunction

Nineteen consecutive cases of flexor hallucis longus stenosing tenosynovitis that underwent operative tenolysis from September 1994 to December 1996 were retrospectively reviewed. This is classically a disorder of ballet dancers, and to a much lesser extent, running athletes. The patients were primarily nonathletic, male, and middle-aged. The mean symptom duration was 20 months, multiple physicians had been encountered, and misdiagnosis was common. Patients presented with overlapping signs and symptoms of flexor hallucis longus tendinitis, plantar fasciitis, and tarsal tunnel syndrome. A cross-reference of patients with posteromedial ankle pain, medial arch pain, and/or a positive Tinel's sign revealed that 14 (74%) and 6 (32%) feet had two of three, or all three signs, respectively. Magnetic resonance imaging and tenography proved valuable in establishing the correct primary diagnosis. Nonoperative protocols were unsuccessful. Flexor hallucis longus tenolysis was successful in each case with a mean return to regular activity at 9 weeks. Flexor hallucis longus stenosing tenosynovitis may be more prevalent than reported and should be a diagnosis of inclusion among all patient populations who present with posterior ankle, medial arch, and/or tarsal tunnel symptoms.

Pain in the posterior aspect of the ankle in dancers. Differential diagnosis and operative treatment

A retrospective review was performed of the results of operative treatment of stenosing tenosynovitis of the flexor hallucis longus tendon or posterior impingement syndrome, or both, in thirty-seven dancers (forty-one operations). The average duration of follow-up was seven years (range, two to thirteen years). The results were assessed with use of a questionnaire for all patients, and a clinical evaluation was performed for twenty-one patients (twenty-two ankles). Twenty-six operations were performed for tendinitis and posterior impingement; nine, for isolated tendinitis; and six, for isolated posterior impingement syndrome. A medial incision was used in thirty-three procedures; a lateral incision, in six; an anterior and a medial incision, in one; and a lateral and a medial incision, in one. Thirty ankles had a good or excellent result; six, a fair result; and four, a poor result. (The result of the second procedure on an ankle that was operated on twice was not included.) The result was good or excellent for twenty-eight of the thirty-four ankles in professional dancers, compared with only two of the six ankles in amateur dancers.

Release of the flexor hallucis longus tendon in ballet dancers

Thirteen female ballet dancers had an operative release of the flexor hallucis longus tendon because of isolated stenosing tenosynovitis, and the results were reviewed after a mean duration of follow-up of six years and six months (range, two to ten years). All of the patients danced at the advanced or professional level, and all had failed to respond to non-operative management. The mean age of the patients at the time of the operation was twenty years (range, thirteen to twenty-six years). Symptoms, which included pain and tenderness over the medial aspect of the subtalar joint, had been present for a mean of six months (range, two to twelve months) preoperatively and were exacerbated by jumping and by attempts to perform en pointe work. Crepitus was present in six patients, and triggering was present in three. No patient had evidence of a symptomatic os trigonum. Postoperatively, all patients participated in a formal physical-therapy program for a mean of nine weeks (range, four to thirteen weeks). All patients returned to dancing, within a mean of five months (range, two to nine months), and eleven reached a level of full participation in dancing without restriction. At the time of the most recent follow-up, all patients noted improvement compared with the pre-operative condition. Eight patients were professional ballet dancers, four were students at advanced ballet schools, and one had stopped performing ballet for reasons unrelated to the tenosynovitis of the flexor hallucis longus. In addition, two of the students had decided not to pursue careers in dancing because of persistent, but greatly diminished, symptoms. No complications were noted in this series. We concluded that an operative release of the flexor hallucis longus is effective for the treatment of isolated stenosing tenosynovitis in female ballet dancers who place high demands on the foot and ankle and for whom non-operative treatment has failed.

Fractures of the distal shaft of the fifth metatarsal. "Dancer's fracture"

We retrospectively reviewed the office records of the senior author--which include two national ballet companies--and identified 35 dancers who sustained distal shaft fractures of the fifth metatarsal. The usual fracture pattern is a spiral, oblique fracture starting distal-lateral and running proximal-medial. Treatment consisted of open reduction and internal fixation for 2 patients, closed reduction and percutaneus fixation for 2 patients, short leg weightbearing cast for 7 patients, and an elastic wrap and treatment of symptoms for 24 patients. Patients with marked displacement of the fracture underwent internal fixation early in the study period; but more recent treatment emphasized nonoperative means, even for displaced fractures. The average time to pain free walking was 6.1 weeks (range, 0 to 16); return to barre exercises, 11.6 weeks (range, 4 to 48); and return to performance, 19 weeks (range, 6 to 52). There was one delayed union (7 months) and one refracture (2 months) that subsequently healed. All patients returned to professional performance without limitation and no patient reported pain with performance at followup. Spiral fractures of the distal shaft of the fifth metatarsal are common injuries and can usually be treated nonoperatively for these high performance athletes without long-term functional sequelae.

Hallux valgus in ballet dancers: a myth?

Among dancers it is widely believed that ballet dancing induces hallux valgus. Revision of radiographs of 63 active and 38 retired dancers of both sexes showed no increase in the valgus angulation of the hallux compared with that of nondancers.

Exercise and the musculoskeletal system

1. Normal joints in individuals of all ages may tolerate prolonged and vigorous exercise without adverse consequences or accelerated development of OA. 2. Individuals who have underlying muscle weakness or imbalance, neurological abnormalities, anatomical variances, and who engage in significant amounts of exercise that stress the lower extremities, may accelerate the development of OA. 3. Individuals who have suffered injuries to supporting structures may also be susceptible to accelerated development of OA in weight-bearing joints, even without increased stress to the joint from exercise. 4. Certain individuals with established degenerative or inflammatory arthritis may benefit from supervised exercise programmes. 5. Still more information is needed so that physicians can identify subjects at risk for the development of OA, advise the millions of participants about the beneficial and deleterious effects of regular exercise and sports participation, and develop successful rehabilitation programmes for injured joints.

Musculoskeletal problems of performing artists

We have reviewed the frequency and variety of rheumatic problems among performing artists. For instrumentalists, injuries are related to the type of instrument played, the technique used and the effort expended in the quest for excellence. For dancers, musculoskeletal problems too reflect technique and effort. We should not be surprised at the frequency of these problems. Rheumatologists, as well as orthopaedic surgeons, physiotherapists, neurologists and other physicians, encounter performing artists as patients. We should be familiar with their problems and be able to knowledgeably diagnose and manage them. This may include observing the artist during actual performances. How is the instrument being held? What is the posture of the artist? What are the comments of the coach or teacher. What type of shoes does the ballerina wear? What movements in particular cause discomfort? These and similar observations will have direct bearing on the musculoskeletal problems of these artists. Published studies have related the variety, frequency and disabling nature of performance-related musculoskeletal problems. Unfortunately few if any of these are controlled, blinded or prospective. We need more and better information. We will want clear information about prevalence of problems, better definition of the musculoskeletal ailments, classification of the relationship of problems with performance and individual biomechanical features, information about response of specific problems to interventions, and data about the long-term consequences, if any, of these rheumatic problems to the musculoskeletal system. Artists as patients are unique. Minor problems can become potentially career-ending disabilities. Making music or performing dance may provide us with delightful entertainment but represents a source of livelihood to artists. Understanding their medical needs and enabling them to continue to perform is the challenge before us.

Injury in ballet: a review of relevant topics for the physical therapist

Currently, there is a need for a review of the literature on ballet injury as it pertains to the physical therapist. Relatively few articles have reviewed ballet injury prevalence and mechanisms of injury. The purpose of this paper was to provide a thorough literature review of the prevalence of ballet injury and mechanisms of injury. Environmental factors and footwear relating to ballet injury were also reviewed. The literature indicated that 65-80% of ballet injuries are in the lower extremity, 10-17% occur in the vertebral column, and most of the remaining percentage are upper limb injuries (5-15%). The etiology of common lower limb conditions included an incorrect turnout; soft tissue imbalances; reduced quadriceps performance; "rolling in of the foot;" inversion sprains; and frequent pliés, pointé, and demipointé work. Spinal conditions were reported to result from hyperextension and hyperlordosis of the lumbar spine as well as the psoas insufficiency syndrome. It was revealed that inappropriately fitting footwear lead to various foot conditions and abnormal lower kinetic chain biomechanics. Environmental factors, such as the dance surface, also have implications in ballet injury. The author concluded that ballet injuries have a multifactorial etiology that primarily involves the interplay of compensatory biomechanics in the spine and lower extremity, environmental factors, and footwear. In addition, some clinical recommendations have been made regarding the physical therapy management of ballet injuries.

A profile of the musculoskeletal characteristics of elite professional ballet dancers

Twenty-eight principal dancers and soloists from America's two most famous ballet companies were examined for anthropometric measurements, including flexibility, muscle strength, and joint range of motion. Both male and female dancers were flexible, but not hypermobile, and did not differ significantly from each other. Marked differences were found between the range of motion of the hip and ankle in the dancers and the norms for the general population. The increased external rotation of the hip in women was accompanied by a loss in internal rotation, resulting in an increased range of motion with an externally rotated orientation. The men, however, lost more internal rotation than they gained in external rotation. These data raise the possibility of a torsional component to the turned-out hip position in elite female professional ballet dancers. In addition, significant anatomic differences separate elite dancers of both sexes from the normal population.

A technique for measuring absolute toe pressures: evaluation of pressure-sensitive film techniques

Although a number of pathologies of the forefoot in ballet dancers on pointe have been described, pressures and deforming forces have not been adequately measured. To evaluate the possible use of pressure-sensitive film (PSF) in measuring the pressures on the external soft tissues in such a confined space as the dancer's toe shoe, it was tested and calibrated with 20 cadaver toes. Each cadaver toe was internally stabilized and loaded longitudinally against PSF on a flat surface. The resultant films were analyzed with a video imaging system and the pressures and total forces were determined. Results showed that the linearity of the PSF to pressure had a regression value of 0.98. By using two sensitivity ranges of films, the total force measured by the PSF was found to be within 10% of the known applied force on each toe. The PSF, therefore, may very well be a useful and accurate method of measuring external soft tissue pressures on the forefoot.

Analysis of the forefoot on pointe in the ballet dancer

The forefoot positions of nine ballet dancers standing on pointe were determined using a mold technique. These molds revealed three positions of the toes: (1) no crossing of the three medial toes; (2) crossing of the third toe behind the second; and (3) crossing of the hallux partially in front of the second. Almost half of all the toes seen on the molds had some deformation of the toenails. These molds also indicated a wide variability in the amount and location of contact between the shoes and toes.

Relationship of turnout to hip abduction in professional ballet dancers

The ability to externally rotate or turn out the hip is fundamental to ballet. Every classical dancer aims to achieve perfect turnout. The purpose of this study was to determine how much turnout is necessary for maximal abduction. It was hypothesized that moderate turnout is sufficient for this purpose. Twenty-two professional dancers from the Alberta Ballet Company were studied. Measurements of passive hip abduction were taken at 0 degree, 45 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees and maximum hip lateral rotation using a goniometer and Leighton flexometer. Statistical analysis was done using Pearson correlation coefficients. A significant positive correlation was found between abduction and lateral rotation (P less than 0.05). The greater the position of external rotation, the more abduction achieved. In conclusion, the traditional emphasis on good turnout has some scientific merit and functional implications.

Personality, stress, and injuries in professional ballet dancers

Twenty-nine soloist and principal dancers (mean age, 29.08 years) from America's two most celebrated ballet companies were administered questionnaires measuring personality (API), occupational stress (OES), strain (PSQ), and coping mechanisms (PRQ), and injury patterns. The results revealed that male dancers demonstrated significantly more negative personality traits and psychological distress than female dancers or men in the general population. In addition, physical stress and personality traits, characteristic of the "overachiever," distinguished injured dancers. It is suggested that classical ballet's emphasis on the ballerina may be at odds with a masculine identity in male dancers. Furthermore, the qualities that lead to success in this profession may contribute to injuries if carried to an extreme.

Articular mobility in ballet dancers. A follow-up study after four years

A follow-up study of ballet dancers was conducted to determine the influence of 4 years additional training on articular mobility using Beighton's method. The score increased in 25 (45.5%) of the 55 dancers reexamined. Acquired forward flexion accounted for this increase in 21 (84%) of the 25 dancers. These 21 dancers had had significantly less training than had the 30 dancers who could forward flex when examined initially (P less than 0.0001), showing that forward flexion is acquired through training. There were significantly more hypermobile individuals among dancers who had continued dancing than among those who had stopped (P less than 0.03). However, only 2 (16.7%) of 12 dancers who had progressed in their careers were hypermobile. We conclude that 1) most ballet dancers are able to forward flex, 2) forward flexion is usually acquired and develops after 4 or more years of training, 3) the mobility score may assist in predicting who will continue dancing, but that 4) there is no association between hypermobility and dancing excellence.

A Physiologic Profile Comparing Levels and Styles of Female Dancers

In brief: A physiologic profile comparing 39 female dancers was undertaken to better understand the factors distinguishing four levels and styles of dance: professional ballet (PB), professional modern, university ballet, and university modern. The PB dancers had significantly lower VO2 max values on the tread-mill as well as lower peak blood lactate levels following the Wingate test for anaerobic capacity than the other dancers. The PB dancers also had a significantly higher isokinetic hamstring-quadriceps ratio than the modern dancers. These findings suggest that physiologic capacity may differ among female dancers according to their levels and styles of dance.

Isokinetic characteristics of the knee in female, professional and university, ballet and modern dancers*

*Study conducted as part of thesis submitted by R.D.C. in partial fulfillment of the requirements for the degree of Master of Science. The purpose of this investigation was to evaluate isokinetic characteristics of the knee in female, ballet and modern, professional and university dancers in order to evaluate possible differences among the groups. A total of 37 dancers with a mean age of 24.9 years was tested using a Cybex II dynamometer. A multiple analysis of variance (MANOVA) indicated that the ballet dancers had significantly higher H/Q ratios than modern dancers at three speeds (p < 0.024). Post hoc procedures indicated that the professional ballet dancers (PB) had significantly higher H/Q ratios than all other groups at 180 degrees /sec (p < 0.05). Also, although most of these dancers demonstrated normal peak torque/body weight values for knee extension and flexion, specific weaknesses were observed in the force decay rate of the quadriceps curves. It was concluded that these theatrical dancers were not a homogeneous group in terms of certain isokinetic characteristics.J Orthop Sports Phys Ther 1988;9(12):410-418.

Transverse tibial stress fractures. A special problem

Five transverse tibial stress fractures have been reviewed. Two of three cases in the anterior midtibia and one in the proximal posteromedial tibia had radionuclide scans. These cases demonstrated minimal scan activity at the stress fracture site. This minimal scan activity in patients with a clinical history of pain and a tender mass suggests poor bone reparation and nonunion. One anterior midtibial stress fracture developed a complete fracture. A proximal anterior tibial ridge stress fracture revealed radiological and clinical evidence of healing.

Kappa Delta Award paper. Osteoregulatory nature of mechanical stimuli: function as a determinant for adaptive remodeling in bone

The capacity for functional adaptation within the skeleton was studied using the functionally isolated turkey ulna preparation. The results of this study would suggest that adaptive bone remodeling is extremely sensitive to alterations in both the magnitude and distribution of the strain generated within the bone tissue. At present, it appears that a loading regime can only influence bone remodeling when it is dynamic in nature. The full osteogenic potential of its influence is then achieved after only an extremely short exposure to this stimulus. The potency of the stimulus appears to be proportional to the magnitude of the strain engendered. As strain levels that are acceptable in one location induce adaptive remodeling in others, it would appear that each region of each bone is "genetically programmed" to accept a particular amount and pattern of intermittent strain as "normal." Deviation from this "optimal strain environment" will stimulate changes in the bone's remodeling balance, resulting in adaptive increases or decreases in its mass.

Technique as a Consideration in Modern Dance Injuries

In brief: Modern dance encompasses many different techniques, each of which makes unique demands on the dancer's body. When these demands are amplified by the repetition required to learn and use any technique, overuse injuries sometimes result. To provide a data base for studying injuries in a significant sample of the modern dance community, we surveyed 164 modern dancers, who reported a total of 229 injuries over the past five years. Injury sites and frequency varied with the dance technique. For example, the rate of knee injuries was higher among dancers using the Graham technique than among those using the Horton technique (25% and 10.8%, respectively), whereas lower back injuries occurred more frequently in Horton than in Graham dancers (21.6% and 16.7%, respectively). Hence, technique is a factor to consider when studying modern dance injuries.

Arthroscopic Assessment and Treatment of Dancers' Knee Injuries

In brief: The author saw 16 dancers with a history of dance-related knee injuries that had defied conservative treatment. Arthroscopic examination revealed 15 meniscal tears and four cases of chondromalacia patellae. The meniscal tears were treated by partial arthroscopic meniscectomy and the chondromalacia patellae by shaving, drilling, and debridement of the patella. After surgery the results were rated by means of a physical examination and a patient questionnaire. The results were generally excellent, with 13 of the 16 dancers returning to a preoperative level of dance activity. However, the author stresses the importance of preventing injury by using correct dance technique, wearing knee pads during practice, and avoiding excessively hard floor surfaces.

Foot and ankle injuries in theatrical dancers

The theatrical dancer is a unique combination of athlete and artist. The physical demands of dance class, rehearsal, and performance can lead to injury, particularly to the foot and ankle. Ankle sprains are the most common acute injury. Chronic injuries predominate and relate primarily to the repeated impact loading of the foot and ankle on the dance floor. Contributing factors include anatomic variation, improper technique, and fatigue. Early and aggressive conservative management is usually successful and surgery is rarely indicated. Orthotics play a limited but potentially useful role in treatment. Following treatment, a structured rehabilitation program is fundamental to the successful return to dance.

The adolescent ballet dancer. Nutritional practices and characteristics associated with anorexia nervosa

A questionnaire was administered to 45 female ballet dancers aged 12-21 years and 44 nonathletic female subjects aged 14-16 years. Dietary practices and nutrition beliefs of the dancers were assessed, and a comparison was made of the prevalence of anorexia nervosa characteristics among the two groups. Ballet dancers reported characteristics of anorexia nervosa significantly more often than did controls. Characteristics used to differentiate between the groups were underweight (p less than 0.05), distorted body image (p less than 0.005), amenorrhea (p less than 0.02), and binge eating (p less than 0.005). Nutrition practices and beliefs among adolescent ballet dancers included frequent use of weight reduction strategies such as fasting, binging, and selective food restriction. Supplements were used by 60% of the dancers, primarily a multivitamin or vitamin C supplement. Fluids or carbohydrates wer not viewed as an important aid to performance by the majority of dancers. This study indicates the need for improved education for ballet dancers, coaches, trainers, and parents, including information on nutrition needs and the management of behaviors associated with anorexia nervosa.

Aerobic Dance Injuries: A Retrospective Study of Instructors and Participants

In brief: In this study shoes, floor types, and individual physical differences were evaluated for their effects on aerobic dance injuries. The injury frequency was 75.9% for instructors and 43.3% for students. The shin was the most common site of injury in both groups. Overall, 60% of the injuries in the student group and 52% of injuries in the instructor group occurred below the knee. Most injuries were not debilitating, and few required medical treatment. The authors concluded that resilient but stable floor surfaces, proper shoes, and moderating the frequency of participation can prevent injuries in aerobic dance.

Aerobic Dance Injuries: A Survey of Instructors

In brief: The authors surveyed 135 instructors about the incidence of injuries and associated factors related to aerobic dance. The instructors had a high number of overuse injuries. Many instructors and students were dancing on nonresilient surfaces and were wearing inappropriate shoes. Many instructors may have exceeded their limits of tolerance to mechanical impact shock trying to maintain high levels of aerobic exercise.