Musculoskeletal injuries in young ballet dancers

Acute Musculoskeletal Complaints Vary According to the Perceived Stress Among Hungarian Professional Dancers

Introduction: Studies showed that professional dance is often associated with a high degree of acute musculoskeletal injuries. These injuries' etiology predominantly describes their biomechanical or other extrinsic factors, but there is a limited number of scientific reports dealing with the perceived stress or mental health status concerning the physical complaints especially, among Hungarian professional dancers. Materials and Methods: In this study, we used validated questionnaires (RESTQ, SEFIP, Mental Health Test) filled out by Hungarian professional female dancers (N = 168) via an online platform anonymously and analyzed statistically. Results: Our findings showed a significantly positive relationship between musculoskeletal complaints and perceived stress, an elevated level of general stress, and a higher level of resilience in this population compared to the general population. Conclusion: Dancers demonstrate a heightened perception of stress; however, they exhibit elevated scores on resilience assessments, indicative of heightened functionality in their daily lives. Stress, per se, may not be directly regarded as a causative factor for acute musculoskeletal conditions, but it could potentially influence the severity of pain sensations and subjective pain levels in the context of existing injuries. Additional investigations are warranted to elucidate the precise mechanisms by which stress exacerbates the pain experience among dancers.

Umbrella review of musculoskeletal injury burden in dancers: implication for practice and research

BACKGROUND

Dancers are susceptible to injury. Nevertheless, injury epidemiology research in dancers is inconsistent. Furthermore, ballet dancing has dominated the huge body of reviews analyzing the epidemiology of musculoskeletal injuries in a variety of artistic dance forms, making it challenging to acquire a thorough, comprehensive, and understandable reporting of the available data.

PURPOSE

The overview and reanalysis of dancers' musculoskeletal pain and injury load across artistic dance forms.

STUDY DESIGN

Systematic review of systematic reviews and meta-analysis.

METHODS

A search was conducted online for literature written in English using PubMed and Google Scholar (2012-2021). The data gathered was then analyzed using predetermined qualifying criteria.

RESULTS

12 reviews were determined to be qualified, the majority of which had moderate to low confidence and raised concerns about bias based on JBI-URARI and ROBIS. The prevalence of dance-related musculoskeletal injuries ranged from 26% to 84% in any artistic dancers and 42% to 343% in ballet dancers. The incidence was less than 5 per 1000 dance hours in both groups, with lower extremities and back being the commonly reported sites. Reviews themselves stated that the quality of the reviews was often poor. Due to the study's heterogeneity and methodological inconsistency, data pooling and meta-analysis were not possible.

CONCLUSION

The current review emphasizes the gaps and restrictions in the dance epidemiology literature that make it challenging to quantify and report a single overall injury rate for dancers. These results underline the need for better primary investigations and evidence synthesis. As injury epidemiology is a critical component of the overall injury-prevention puzzle, there is a need for standardization in future research, particularly with active and prospective injury surveillance, injury classification, injury evaluation, and injury reporting.

LEVEL OF EVIDENCE

Systematic Review, Level III.

Dance-related musculoskeletal injury leading to forced time-loss in elite pre professional dancers - a retrospective study

OBJECTIVES

Describe the epidemiology of dance-related musculoskeletal injury leading to forced time-loss in elite pre-professional dancers and provide descriptive data on the prevalence concerning diagnoses, location, and injury type, stratified by gender and skill level.

METHODS

Retrospective cohort, over a 3-year period on a full-time pre-professional Portuguese dance school featuring 70 both gender students with a mean age of 14.87 years. A total of 110 injuries were analyzed. Non-parametric statistics were used.

RESULTS

The most prevalent diagnosis leading to forced time-loss in female dancers were Medial Tibial Stress Syndrome (MTSS), 14.29%, and Posterior Ankle Impingement Syndrome (PAIS), 7.14%, whereas in male dancers these were Hallux Sprain, 17.50%, and Lumbar Spine Joint Injuries, 7.50%. Differences were found in injuries' anatomical location between genders and in Incidence Proportion and Clinical Incidence between skill levels. 72.20% of the chronic injuries and 50.00% of the acute injuries occurred in Level III students.

CONCLUSIONS

With respect to forced time-loss injuries, male dancers were found to sustain more acute traumatic injuries and female dancers overuse, respectively, sprains and MTSS and PAIS. Identifying which injuries are most likely to lead to forced time-loss may be useful for helping health-care professionals in clinical decision-making and in developing more effective injury prevention and management strategies.

Systematic review of methods used to measure training load in dance

Dance is a popular physical activity. Increased dance training has been associated with an increased risk of injury. Given the established association between training load (TL) and injury in sport, knowledge of how TL is currently being measured in dance is critical. The objective of this study is to summarise published literature examining TL monitoring in dance settings. Six prominent databases (CINAHL, EMBASE, Medline, ProQuest, Scopus, SportDiscus) were searched and nine dance-specific journals were handsearched up to May 2022. Selected studies met inclusion criteria, where original TL data were collected from at least one dancer in a class, rehearsal and/or performance. Studies were excluded if TL was not captured in a dance class, rehearsal or performance. Two reviewers independently assessed each record for inclusion at title, abstract and full-text screening stages. Study quality was assessed using Joanna Briggs Institute Critical Appraisal Tool checklists for each study design. The 199 included studies reported on female dancers (61%), ballet genre (55%) and the professional level (31%). Dance hours were the most common tool used to measure TL (90%), followed by heart rate (20%), and portable metabolic systems (9%). The most common metric for each tool was mean weekly hours (n=381; median=9.5 hours, range=0.2-48.7 hours), mean heart rate (n=143) and mean oxygen consumption (n=93). Further research on TL is needed in dance, including a consensus on what tools and metrics are best suited for TL monitoring in dance.

Artistic Swimming Injuries in Young Elite Athletes: An 11-year Follow-Up

OBJECTIVE

Artistic swimming is a highly challenging discipline, requiring physical skills and creativity. There are almost no published data on trauma. We aimed to assess the incidence and the nature of injuries in artistic swimmers.

DESIGN

An 11-year retrospective single-center cohort study.

SETTING

Department of Sport Medicine of a University Hospital.

PATIENTS

One hundred and twenty-four elite female artistic swimmers aged 12.9 ± 1.6 years.

INTERVENTIONS

The cohort was divided into 3 groups according to the competition categories (from 9 to 12 years old called "future", 12-15 years old called "youth", 15-19 years old called "junior").

MAIN OUTCOME MEASURES

Injury rate per season and per athlete was assessed.

RESULTS

The injury rate was 0.95 injuries/season/athlete and 1.05 injuries/1000 hours of practice. The most frequent injuries were rotator cuff tendinopathy (13.6%), acute low back pain (13.6%), and patellofemoral syndrome (11.9%). Swimmers in the youth and junior categories had significantly more injuries than those in the future category (P = 0.009), possibly because of more training hours (P < 0.001). Twelve major injuries occurred, all in the same group of youth swimmers.

CONCLUSION

This is the first study investigating trauma during artistic swimming practice. A better knowledge of the main injuries is necessary for the physician to provide optimal care for athletes and to develop prevention. Attention should be particularly paid to the swimmers' shoulders and knees.

The interactions between agonist-to-antagonist muscle strength performance and plantar pressure distribution, foot contact area, and impulse in novice ballet dancers

BACKGROUND

Hip, trunk, knee, and ankle/foot muscles may lead to increased variability in the components of balance and plantar pressure distribution (PPD) analysis. However, the role of these muscle groups in the PPD of different ballet techniques in novice ballet dancers has not previously been studied.

OBJECTIVE

Our objective was to examine whether balance and PPD vary among five different ballet techniques and correlate with the agonist-to-antagonist strength performance of trunk, knee, hip, and ankle muscles in adolescent ballet dancers.

METHODS

The anthropometric parameters, muscle strength performance, balance, and PPD of sixty healthy female ballet dancers (age: 14.36 ± 2.18 y) were measured at 48-h intervals.

RESULTS

The forefoot's PPD was significantly greater than the midfoot and rearfoot for all techniques (p= 0.000). The percent plantar load of forefoot during développé à la seconde (side, front, back), passé, and penché was greater than midfoot (166.56%, 161.51%, 168.11%, 165.14%, 174.04%) and rearfoot (47.75%, 32.84%, 43.83%, 48.73%, 49.66) for all techniques, respectively. The forefoot's PPD, impulse, and contact area during all techniques were significantly correlated with the trunk muscle strength ratio (p< 0.05).

CONCLUSION

Ballet dancers with higher trunk muscle strength imbalance showed a greater percentage difference in pressure load between the left and right foot in the anterior and posterior directions, poor balance, aggravated trunk imbalance, increased PPD, contact area, and impulse in the forefoot during each technique.

Body asymmetries as risk factors for musculoskeletal injuries in dancesport, hip-hop and ballet dancers?

OBJECTIVES

The study aimed to determine the incidence and expression of body asymmetries in dancers of three different dance styles: dancesport (n = 14), hip-hop (n = 21) and ballet (n = 20) and to examine how body asymmetries (muscle strength and power, stability and range of motion) are associated with musculoskeletal injuries occurring over the past 12 months.

DESIGN

Cross-sectional and retrospective study.

METHODS

Maximal isometric voluntary contraction was measured for trunk, hip, knee and ankle movements. Participants performed a single leg stance, unilateral landing, weight bearing symmetry, squat and countermovement jump on force platforms. Passive range of motion was measured for hip, knee and ankle with two-arm goniometer or digital inclinometer (hip flexion, extension and rotations). A retrospective questionnaire was used to collect data on musculoskeletal injuries occurring in the last 12 months.

RESULTS

Different dance styles were associated with different body asymmetries, including strength asymmetries (hip flexion and external rotation), agonist/antagonist asymmetries (trunk flexion/extension, hip abduction/adduction, ankle dorsi/plantar flexion) and hip adduction and internal rotation range of motion asymmetries. Moreover, strength asymmetries of hip flexion, adduction and abduction/adduction as well as stability asymmetries were associated with the total number of musculoskeletal injuries.

CONCLUSIONS

The incidence of body asymmetries (> 10%) in dancesport, hip-hop and ballet dancers was confirmed, as well as the association of some asymmetries with self-reported injuries occurring over the last 12 months. The cause-effect relationship should be clarified by further studies.

Pediatric Musculoskeletal Injuries

Musculoskeletal injuries are a common reason for emergency department and primary care visits in the pediatric population. The prevalence of these injuries is likely related to children and adolescents participating in sports activities, physical activity, and exercise that can lead to these injuries. It is important for health care professionals and practitioners to understand the assessment, evaluation, and treatment of musculoskeletal injuries, but also to understand when to refer for expert consultation. [Pediatr Ann. 2022;51(9):e330-337.].

Ballet Rehabilitation: A Novel Return to Sport Protocol

Dance injuries and re-injuries are common but can be difficult to rehabilitate because of the unique demands and motor skills required. During tissue healing, pain resolves prior to tissue maturation and re-injury often occurs if the original injury is not properly rehabilitated.

The purpose of this narrative review is to analyze the existing literature addressing ballet injury, re-injury, and recovery, and to provide clinicians with timing guidelines for entering and implementing a Return to Sport (RTS) ballet rehabilitation protocol designed to prevent re-injury by progressive, sport-specific tissue loading. Thus far, a literature-based ballet-specific and body region-specific late-stage rehabilitation RTS protocol has not been established. The authors sought to address this literature gap by combining this comprehensive narrative review with our extensive clinical expertise to develop a late-stage rehabilitation RTS protocol to help guide medical clinicians treating injured ballet dancers.

Injury Rates and Characteristics Associated with Participation in Organized Dance Education: A Systematic Review

INTRODUCTION

Several studies and recent systematic reviews have investigated injury in dance settings and have largely focused on specific concert dance genres (i.e., ballet, contemporary) and elite levels (i.e., pre-professional, professional) of dance. Less is known about the health of those who participate in dance education settings, namely teachers and students from private dance studios. Given that these individuals constitute a large proportion of the dance community, greater clarity of risks in the dance training environment could benefit an underserved majority by informing the development of effective injury prevention strategies.<br/> Objective: The primary objective was to describe injury rates and characteristics associated with participation in organized dance education settings.<br/> Methods: Six electronic databases were searched to April 2021 (Medline, EMBASE, SportDiscus, CINAHL, SCOPUS, Cochrane). Selected studies met a priori inclusion criteria that required original data from dance teacher and student samples within formal dance education settings. All genres of dance were eligible. Studies were excluded if no injury outcomes or estimates of dance exposure were reported, if injuries occurred during rehearsal and performance, or if dance was used as a therapeutic intervention or exercise. Two reviewers independently assessed each paper for inclusion at abstract and full text screening stages. The quality of included studies was assessed using the Joanna Briggs Institute Level of Evidence tool.<br/> Results: The initial database search identified 1,424 potentially relevant records, 26 were included and scored. Most studies (n = 22) focused on dance students only, three included only dance teachers, and one study included both. Among both dance students and teachers, the majority of injuries reported were overuse or chronic and involved the lower limb. For studies that reported injury rates (n = 14), estimates ranged from 0.8 to 4.7 injuries per 1,000 dance hours, 4.86 per 1,000 dancer-days, and 0.21 to 0.34 per 1,000 dance exposures.<br/> Conclusions: Based on the current research, dance students and teachers experience a similar rate of injury to concert and professional dancers, and their injuries are most commonly overuse injuries involving the lower extremity. There have been few high-quality investigations of injury specific to the dance training environment. Therefore, consensus around the burden of injury in the dance education settings remains difficult. Future dance epidemiological investigations that examine the burden of injury among dance teachers and students, include operational injury and exposure definitions, and utilize prospective designs are warranted.

The Relationship of Year Group and Sex on Injury Incidence and Countermovement Jump in Adolescent Ballet Dancers: A Cross-Sectional Analysis

INTRODUCTION

Pre-professional ballet training involves long training hours from an early age that could influence young dancers' physical performance and injury incidence. This cross-sectional analysis investigated the relationship of year group and sex with countermovement jump and injury incidence (primary outcome) in adolescent ballet dancers at a pre-professional dance school.

METHOD

Countermovement jump (CMJ) height was recorded at the start of the academic year for 179 participants (M = 68, F = 111) spread across eight year-groups. Injury etiology and incidence was prospectively recorded over a 6-month period (September through February) by the medical team using a time-loss definition.

RESULTS

Between-subject statistically significant differences were reported for sex [F(1, 153) = 101.46; p < 0.001], year group [F(7, 153) = 12.57; p < 0.001], and sex*year group [F(7, 153) = 9.22; p < 0.001]. Mean CMJ across the year groups ranged between 24.7 to 41.3 cm for males and 23.5 to 25.1 cm for females. Injury incidence per dancer was 0.84 (CI: 0.13, 1.56) and injury incidence per 1,000 hours of dance was 1.94 (CI: 1.63, 2.25). No statistically significant differences between sexes or year groups were reported for injury incidence per 1,000 dance hours and time-loss. Hours dancing was statistically significantly positively associated with CMJ (r = .481, p < 0.05) and negatively associated with injury incidence (r = -.253, p < 0.05) for males; for females it was positively associated with time-loss (r = .254, p < 0.05).

CONCLUSION

Even though CMJ was cross-sectionally monitored, the expected increased physical abilities in males as they grew older and progressed through their training was observed. Females did not indicate a similar increase in their physical ability, but they seemed to become more susceptible to injuries as they grow older. The lack of this speculative physiological development for the females may be associated with the ballet-only approach in their training. The use of CMJ as an injury screening tool may be limited, however, it could still be used as a tool to monitor physiological and fundamental motor skill development of adolescent dancers, as jumping is an integral part of ballet.

Neuromuscular Training in Pre-Professional Ballet Dancers: A Feasibility Randomized Controlled Trial

INTRODUCTION

It is well documented that there is high prevalence of injuries in pre-professional and professional ballet dancers. Current evidence from high in quality and quantity research on injury prevention in sport indicates that interventions can reduce injury risks by 30% to 50%. Injury prevention research in dance is limited. The aim of this study was to assess the feasibility (adherence, fidelity, and practicality) of a randomized controlled trial for the utilization of neuromuscular training in pre-professional ballet dancers.

METHODS

A convenience sample of 22 pre-professional ballet dancers were randomized into an intervention and control group. The intervention group took part in a neuromuscular-based training workout, five times per week before the ballet class, for 10 weeks. The intervention was an adaptation of the FIFA 11+, an injury prevention intervention and is called 11+ Dance. The intervention consisted of low intensity bodyweight exercises that lasted 20 to 30 minutes performed daily.

RESULTS

Intervention adherence was 38% ± 8%, with higher participation at the beginning of the study. Attendance for post-testing was low 45% and 36% for the intervention and control group, respectively, mainly due to injury. There were no adverse effects reported, however, the participants reported delayed onset muscle soreness at the beginning of the intervention, indicating that there may be a potential training effect. Fear of muscle hypertrophy and fatigue were also reported as reasons for attrition. The repeated measures ANOVA revealed statistically non-significant differences for the countermovement jump F(1, 9) = 0.36, p = 0.564, 𝜂2p = 0.04; reactive strength index F(1, 7) = 0.02, p = 0.885, 𝜂2p = 0.003; and the isometric mid-thigh pull F(1, 12) = 0.002, p = 0.967, 𝜂2p = 0.000.

CONCLUSION

The results of the study, together with the feedback from the participants, suggest that some protocol modifications are necessary for the feasibility of a randomized controlled trial in a pre-professional setting. The current trial has produced valuable information for the intervention frequency and load prescription.

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.

A Physiotherapeutic Approach to Musicians' Health - Data From 614 Patients From a Physiotherapy Clinic for Musicians (INAP/O)

Currently, the treatment of musicians is an interprofessional approach. Playing-related health complaints may impact the performance of a musician. In Germany, a medical consulting hour for musicians exists, but those for athletes in sports medicine are not so common. The diagnosing and treatment procedure within the physiotherapy consultation for musicians follows a specific concept-b and requires knowledge of instruments and musician-specific complaints. Based on the consulting hour in a clinic in Osnabrueck, 614 case reports were part of this sample, of which 558 data sets were complete. The focus of the analysis is the instrument and the primary complaint. Also, the type of therapy is characterized, and the amount is calculated. Primary complaints of musicians, in general, are found most frequently in the spine and upper extremity. Musician complaints are different between instruments. Instrumentalists have a significantly higher chance to suffer from a primary complaint in the area of the upper extremity. Furthermore, the groups without an instrument (e.g., singing or dancing) are developing complaints in the anatomical area which they primarily use. Therefore, these types of therapy were used: physiotherapy, manual therapy, and osteopathy with an average of 5.9 treatment units. This study underpinned the importance of musician-specific physiotherapy as a profession to treat musicians. Also, an interdisciplinary approach is necessary to treat all aspects of complaints.

Injury Incidence and Severity in Musical Theatre Dance Students: 5-year Prospective Study

Dance injury research has mainly focused on ballet and modern dance with little data on musical theatre dancers. The purpose was to assess the incidence and severity of injuries in a musical theatre dance college over a 5-year period; 198 pre-professional musical theatre dancers (3 cohorts on a 3-year training course) volunteered for the study; 21 students left the course over the study period. Injury aetiology data were collected by an in-house physiotherapy team. Differences between academic year and sex were analysed using a Poisson distribution model; significant difference was set at p≤0.05. In total, 913 injuries were recorded, and more injuries occurred in academic year 1 than year 2 and 3. Overall injury incidence was 1.46 injuries per 1000 hours (95% CI 1.34, 1.56); incidence significantly decreased between year 1, 2 and 3 (p<0.05). There was no significant sex difference for incidence or severity. Most injuries were classified as overuse (71% female, 67% male). Pre-professional musical theatre dancers report a high proportion of lower limb and overuse injuries comparable to other dance genres. Unlike other studies on pre-professional dancers, injury incidence and severity decreased with academic year, even though workload increased across the course.

Choreography-Specific Cross-Training and Conditioning Programs

Because of increased choreographic demands, early specialization, multi-genre dancers, and high incidence of career-ending injuries, there is a need for enhanced training methodologies to address the unique needs of today's professional dancer. It is imperative for company directors, instructors, choreographers, and dance medicine practitioners to consider implementing the most specific conditioning and training programs to prepare their dancers to meet or exceed expectations without resultant injury. Quantifying effectiveness of choreography-specific training programs is an area for further research. The implementation of scientific principles can and should be used to enhance dancers' health, performance, athleticism, and artistry.

Does forced or compensated turnout lead to musculoskeletal injuries in dancers? A systematic review on the complexity of causes

Injury prevalence in dancers is high, and misaligned turnout (TO) is claimed to bear injury risk. This systematic review aimed to investigate if compensating or forcing TO leads to musculoskeletal injuries. A systematic literature review was conducted according to the PRISMA Guidelines using the databases of PubMed, Embase, Emcare, Web of Science, Cochrane Library, Academic Search Premier, and ScienceDirect. Studies investigating the relationship between compensated or forced TO and injuries in all genders, all ages, and levels of dancers were included. Details on misaligned TO measurements and injuries had to be provided. Screening was performed by two researchers, data extraction and methodological quality assessment executed by one researcher and checked by another. 7 studies with 1293 dancers were included. Methodological quality was low due to study designs and a general lack of standardised definition of pathology and methods of assessment of misaligned TO. The studies investigating the lower extremities showed a hip-focus only. Non-hip contributors as well as their natural anatomical variations were not accounted for, limiting the understanding of injury mechanisms underlying misaligned TO. As such no definite conclusions on the effect of compensating or forcing TO on musculoskeletal injuries could be made. Total TO is dependent on complex motion cycles rather than generalised (hip) joint dominance only. Objective dual assessment of maximum passive joint range of motion through 3D kinematic analysis in combination with physical examination is needed to account for anatomical variations, locate sites prone to (overuse)injury, and investigate underlying injury mechanisms.

LOW BACK PAIN AND INJURY IN BALLET, MODERN, AND HIP-HOP DANCERS: A SYSTEMATIC REVIEW

Background

Low back pain is believed to be a common complaint among dancers; however, a comparison across recent research is needed to support or disprove this assertion across genres.

Purpose

To determine the prevalence of low back pain and low back injury in ballet, modern, and hip-hop dancers through a systematic literature review. A secondary goal was to identify trends amongst dance genres, level of mastery, gender, and age, if possible.

Study Design

Systematic Review of the Literature.

Methods

PRISMA search strategy of terms relating to dance and low back pain was conducted within the Pubmed, MEDLINE, SPORTDiscus, Web of Science, and the archives of the Journal of Dance Medicine and Science databases between November 2017 and March 2018. Inclusion criteria were published articles that addressed low back pain or injury in ballet, modern, or hip-hop dance population. Exclusion criteria included studies relating to specific pathologies or studies that did not report specific dance genre. All included articles were assessed for quality using a modified grading evaluation and a Modified Newcastle-Ottawa Risk of Bias assessment.

Results

Twenty-five ballet articles, five modern, and three hip-hop articles met the inclusion criteria, for a total of 33 articles. Twenty-five of the 33 studies relied on a questionnaire to gather data. Risk of bias results ranged from 3-7/10 and quality of studies ranged from Good I to Limited III. Prevalence of low back pain seems relatively high in ballet dance (range: 20.3%-79% of total dancers are affected). Little research exists on the prevalence of back pain in modern or hip-hop dancers, but hip-hop dancers also seem likely to have low back pain (range: 46.6%-85.7% of total dancers are affected). Low back injuries are also present in ballet (range: 2.1%-88% of total injuries), modern (range: 8.6%-21.6% of total injuries), and hip-hop (range: 26.3%-69.6%).

Conclusion

Ballet dancers seem to be at risk for low back pain or injury independent of gender, age or level of mastery; however, there is not enough evidence to draw any conclusions about modern dancers or hip-hop dancers and their risk for low back pain/injury currently. Future higher-level studies are needed with reduced risk of bias.

Level of Evidence

2a.

What goes up must come down, part II: Consequences of jump strategy modification on dance leap landing biomechanics

Knee injuries are common in jumping athletes; modifying jump strategy may impact loads placed on the body and reduce injury risk. The purpose of this study was to determine if modifying strategy in a saut de chat leap to focus on height would decrease sagittal plane knee loading. Biomechanical data were collected while 28 dancers performed saut de chat leaps with instructions to jump far (FAR) or jump high (UP). In the UP condition, there was greater vertical GRF and less braking GRF. Also in UP, lower extremity contact angle was greater (71.3 ± 2.9º FAR; 75.8 ± 3.3º UP; p = 0.0178), peak knee extensor moment was greater (2.8 ± 0.7 Nm FAR; 3.2 ± 0.8 Nm UP; p = 0.01), and peak ankle plantar flexor moment was lower (3.19 ± 0.4 Nm FAR; 2.94 ± 0.4 Nm UP; p < 0.01). A more acute LECA was related to greater braking force and braking force was related to greater knee extensor moments. Despite these relationships, we observed greater knee extensor moments in UP. While the relationship among these whole-body variables and knee joint loading exists, it may not be the primary factor driving load distribution during dance leap landings.

An Injury Prevention Program for Professional Ballet: A Randomized Controlled Investigation

BACKGROUND

Few investigations have examined dance-specific injury prevention programs (IPPs), and no published randomized controlled trials are available that evaluate IPPs for dance.

HYPOTHESIS

The implementation of an IPP will significantly reduce the risk of injury in professional ballet dancers.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

A randomized controlled trial was designed that entailed a superiority model for the intervention group. All professional dancers from a single ballet company were eligible to participate. Randomization and allocation were performed before the start of the season. The control group practiced and performed without change to preexisting standard operating practice. The IPP group was instructed to perform a 30-minute exercise program 3 times per week over the 52-week study period. Injuries were recorded. Standard continuous and categorical data comparisons and correlations were used. Cox proportional hazards regression models for recurrent failures were used wherein the hazard ratio indicates the relative likelihood of injury in the control versus intervention groups.

RESULTS

Of the 52 eligible dancers, 75% (n = 39) participated. Of these 39 dancers, 19 (9 males, 10 females; mean age, 26.6 ± 4.0 years) were randomized to the control group and 20 (11 males, 9 females; mean age, 25.1 ± 5.1 years) to the IPP group. No significant (P > .05) difference was found in baseline demographics between groups. A total of 116 injuries were recorded for the entire study population (49 IPP; 67 control). Traumatic and chronic injuries accounted for 54% and 46% of injuries, respectively. The injury rate was 82% less (IPP hazard ratio, 0.18; z = -2.29; P = .022) in the IPP group after adjustment for confounding variables, and time between injuries was 45% longer (IPP hazard ratio, 0.55; z = -2.20; P = .028) than for controls.

CONCLUSION

The present study is the first prospective randomized controlled investigation of an IPP for professional ballet. The results showed an 82% decrease in injury rate for the intervention group and an extended period from previous injury to subsequent injury.

REGISTRATION

NCT04110002 (ClinicalTrials.gov identifier).

Does Function Determine the Structure? Changes in Flexor Hallucis Longus Muscle and the Associated Performance Related to Dance Modality: A Cross-Sectional Study

Background and Objectives: Flexor hallucis longus pathology is one of the most common conditions of the ankle and foot in dancers, due to the high demand of dance movements performed in an extreme plantar flexion and dorsiflexion range of motion. The objectives of this study were to determine the bilateral differences between the thickness and cross-sectional area of the flexor hallucis longus muscle in dancers, to establish possible differences between dance modalities, and to analyze whether there is a correlation between ultrasonographic parameters or performance variables and the dance modality. Material and Methods: A sample of 50 (29 classical and 21 contemporary) full-time pre-professional female dancers were included in the study. The thickness and cross-sectional area of the flexor hallucis longus muscle were evaluated for both limbs using ultrasound imaging. The range of movement of the first metatarsophalangeal joint was measured using functional extension with maximal ankle plantarflexion, balance was measured in a unilateral stance with the heel raised, endurance was evaluated through a modified heel rise fatigue test, and a counter movement jump to assess the vertical jump performance was measured bilaterally. Results: There were no significant differences recorded between the dominant and non-dominant limbs for each variable, within both groups. Contemporary dancers showed a greater thickness and cross-sectional area of the flexor hallucis longus muscle than classical dancers. However, classical dancers showed an increase of balance, endurance, range of movement of the first metatarsophalangeal joint, and counter movement jump with respect to contemporary dancers. Conclusion: Bilateral symmetry was identified in all variables for both groups. The size and performance of the flexor hallucis longus muscle may be influenced by the specific nature of dance modality.

Analysis of foot structure in young recreational female ballet dancers

Study aim: The human foot is an essential element of the locomotor system. It plays a key role in both the dynamics and the statics of the whole lower limb. The normal structure of the foot determines its mechanical function. During growth and formation of the foot structure, sport activity plays an important role.

The aim of this study was to analyse the structure of the foot in ballet dancers aged 6 to 14 years compared with a clinical reference peer group that did not do ballet.

Material and methods: The study involved 120 girls aged 6 to 14 years (mean age 9.6, sd. 2.4). Sixty of them formed the study group of ballet dancers, and the other 60 formed the reference group. To conduct the measurements, the computer podoscope CQ-ST produced by the CQ Elektronik System, connected to a portable computer, was used.

Results: A few differences were found between the foot structure in young female ballet dancers and their peers. A statistically significant difference was found in the hallux valgus α angle. The left foot of the examined ballet dancers was found to have a larger hallux valgus. A statistically significant correlation was found between the length of time of ballet training and the increase in the α angle values of the left foot and the right foot in the ballet group.

Conclusions: Ballet dancing in childhood may increase the risk of developing hallux valgus, with the tendency of worsening with training time.

Cross-Cultural Adaptation of the Dance Functional Outcome Survey (DFOS) for Spanish Dancers

A growing number of research papers regarding Spanish-speaking dancers justifies the need for an adapted Spanish version of the Dance Functional Outcome Survey (DFOS). The objective of this study was to cross-culturally adapt and validate the DFOS for Spanish-speaking dancers. A sample of 127 healthy and injured professional and pre-professional dancers were recruited. Test-retest reliability of DFOS-Sp was examined using intraclass correlation coefficients. Construct validity compared DFOS-Sp to the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) using Pearson correlations. Principal component analysis identified factors and internal-item consistency. Sensitivity was evaluated by generating receiver operating characteristic and area under the curve analyses. A subgroup of 51 injured dancers were followed across three time-points to examine responsiveness using repeated measures analysis of variance. Injured scores were analyzed for floor and ceiling effects. The DFOS-Sp showed high test-retest reliability (ICC2,1 ≥ 0.92). DFOS-Sp scores had moderate construct validity compared with SF-36 physical component summary scores (r ≥ 0.56). Principal component analysis (PCA) supported uni-dimensionality explaining 58% of the variance with high internal consistency (α = 0.91).Area under the curve (AUC) sensitivity values were excellent (AUC ≥ 0.82). There were significant differences across time (p < 0.001), demonstrating responsiveness to change, with no floor or ceiling effects. The DFOS-Sp demonstrated acceptable test-retest reliability and validity in Spanish-speaking dancers, with comparable psychometric performance to the English-language version.

Effects of SCCO2, Gamma Irradiation, and Sodium Dodecyl Sulfate Treatments on the Initial Properties of Tendon Allografts

Sterile and decellularized allograft tendons are viable biomaterials used in reconstructive surgeries for dense connective tissue injuries. Established allograft processing techniques including gamma irradiation and sodium dodecyl sulfate (SDS) can affect tissue integrity. Supercritical carbon dioxide (SCCO₂) represents a novel alternative that has the potential to decellularize and sterilize tendons with minimized exposure to denaturants, shortened treatment time, lack of toxic residues, and superior tissue penetration, and thus efficacy. This study attempted to develop a single-step hybrid decellularization and sterilization protocol for tendons that involved SCCO₂ treatment with various chemical additives. The processed tendons were evaluated with mechanical testing, histology, scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy. Uniaxial mechanical testing showed that tendons treated with SCCO₂ and additive NovaKill^TM Gen2 and 0.1% SDS had significantly higher (p < 0.05) ultimate tensile stress (UTS) and Young's modulus compared to gamma-irradiated and standard-SDS-treated tendons. This was corroborated by the ultrastructural intactness of SCCO₂-treated tendons as examined by SEM and FTIR spectroscopy, which was not preserved in gamma-irradiated and standard SDS-treated tendons. However, complete decellularization was not achieved by the experimented SCCO₂-SDS protocols used in this study. The present study therefore serves as a concrete starting point for development of an SCCO₂-based combined sterilization and decellularization protocol for allograft tendons, where additive choice is to be optimized.

The physical features suitable for classical ballet training

OBJECTIVE

The aim of this study was to determine the prerequisite physical features of classical ballet education.

METHODS

Students who enrolled and were rejected for the applications of State Conservatory Ballet Main Art Branch in the academic year 2013-2014 and 2014-2015 were compared with their exam results. This study involves defining the physical ability and determining physical fitness by using Eurofit tests including the Flamingo Balance test (FB), Plate Tapping (PT), Sit and Reach (SITR), Standing Broad Jump (SBJ), Handgrip test (HG), Sit Up in 30 Seconds (SU) and Shuttle Run 10 × 5 meter (SR), Heath-Carter somatotyping method and anthropometric measurements which determine ballet students' body type and physical abilities. Sixty-nine girls between 8-11 years old who applied for ballet education at the State Conservatory Ballet Main Art Branch were included in the study. While the average of age, height and weight measurements of enrolled students were 9.40 ± 0.74 year, 1.38 ± 0.08 m and 30.03 ± 4.73 kg respectively, the same dimensions were found in rejected students, i.e. 9.79 ± 0.94 year, 1.40 ± 0.10 m and 35.59 ± 7.31 kg respectively.

RESULTS

Measurements of diameter, circumference and subcutaneous fat were lower (p< 0.05) for enrolled students. The major body type of enrolled students was identified as mesomorphy, whereas the major body type of rejected students was identified as endomorphy. All dimensions of the Eurofit tests, except the strength test, were significantly different in enrolled students (p< 0.05).

CONCLUSIONS

The parameters used in this study can be convenient in objectively evaluating classical ballet education.

Exploring the potential utility of a wearable accelerometer for estimating impact forces in ballet dancers

Excessive forces and/or loading rates during landing may place ballet dancers at risk for overuse injury. The ability to estimate and monitor the landing forces of ballet dancers could help to improve injury prevention and rehabilitation; however, force platforms are not conducive to testing outside of a laboratory. Fortunately, it may be possible to indirectly assess landing forces via a wearable accelerometer. The purposes of this study were to examine the relationship between impact accelerations, recorded via a pelvis-worn accelerometer, and the peak forces and loading rates during performance of a common ballet manoeuvre, and to examine if a wearable accelerometer is sensitive to fatigue-related changes in landing forces. Fifteen ballet dancers continuously performed a ballet manoeuvre until self-determined exhaustion while impact accelerations and landing forces were simultaneously recorded using an accelerometer and force platforms. We observed very strong, positive relationships between the impact accelerations and the peak forces and loading rates during the landings. In addition, the changes in impact accelerations with fatigue paralleled the changes in the peak forces and loading rates. As a result, it appears that a wearable accelerometer could be used to estimate and monitor landing forces in ballet dancers.

A Retrospective Investigation on Age and Gender Differences of Injuries in DanceSport

In spite of the extensive research on incidence site and type of injury in ballet and modern dancers, limited studies on injury in DanceSport have been reported. Therefore, this study determined retrospectively (within last 12 months) incidence, severity, site and type of injury, between gender and age-class in DanceSport. Participants were 97 international sport-dancers (female, 41; male, 56). Sixty-six (69%) dancers reported 96 injuries (1.00 (range = 4)) injuries per dancer) and an injury incidence of 1.7 (range = 14) per 1000 h. Females revealed significantly higher median injury incidence (females, 2.6 (range = 14); males, 1.9 (range = 9), p < 0.05) than males. A total of 61.5% of all injuries recorded were traumatic with a significant gender difference (Wald chi-square = 11.616, df = 1, p < 0.01). Injury severity was 3 (range 240) days with an interaction effect between gender and age-class (Wald chi-square = 251.374, df = 3, p < 0.001). Meanwhile, 72.3% of the dancers reported not including sport specific exercises besides dancing. These findings show gender and age-class differences in injury incidence, type and severity. Therefore, to reduce the likelihood of injuries, the implementation of supplemental DanceSport specific exercises that also considers the gender and age-class anatomical, functional, and choreographic demand differences in the training program should be recognized.

The Beighton Score and Injury in Dancers: A Prospective Cohort Study

CONTEXT

Joint hypermobility has a high prevalence in dancers and may be associated with injury and performance.

OBJECTIVES

To investigate whether total Beighton score can predict injury and to determine the relationship between joint hypermobility and injury, and to report injury demographics.

DESIGN

A prospective cohort injury study.

SETTING

Edge Hill University dance injury clinic.

PARTICIPANTS

Eighty-two dancers (62 females, 20 males).

MAIN OUTCOME MEASURES

Joint hypermobility via the Beighton score ≥4 with lumbar flexion included and removed.

RESULTS

A total of 61 dancers were classified as hypermobile, which was reduced to 50 dancers with lumbar flexion removed. A significant difference existed between pooled total days injured in hypermobile dancers and nonhypermobile dancers with lumbar flexion included (P = .02) and removed (P = .03). No significant differences existed for total Beighton score between injured and noninjured groups with lumbar flexion included (P = .11) and removed (P = .13). Total Beighton score was a weak predictor of total days injured (r2 = .06, P = .51). In total, 47 injuries occurred in 34 dancers, and pooled injury rate was 1.03 injuries/1000 hours. Receiver operating characteristic curve analysis demonstrated an area under the curve of 0.83 for male dancers with lumbar flexion removed, which was considered diagnostic for injury.

CONCLUSIONS

The Beighton score can be utilized to identify dancers who may develop injury. Clinicians should consider the role of lumbar flexion in total Beighton score when identifying those dancers at risk of injury. Different injury thresholds in female and male dancers may aid injury management.

The Epidemiology of Low Back Pain and Injury in Dance: A Systematic Review

BACKGROUND

Dance is a physical pursuit that involves loading the spine through repetitive dynamic movements and lifting tasks. As such, low back pain (LBP) and low back injury (LBI) have been identified as common health problems in contemporary and classical ballet dancers. However, clarity regarding the experience of LBP and LBI in dance is lacking.

OBJECTIVES

To systematically review and synthesize the epidemiology of LBP and LBI in dance populations.

METHODS

A comprehensive search of 6 electronic databases, back catalogs of dance science-specific journals, and reference lists of relevant articles and a forward citation search were performed.

RESULTS

Fifty full-text articles were included in the final systematic review. There was considerable methodological heterogeneity among the included studies. The median (range) point, yearly, and lifetime prevalence of LBP was 27% (17%-39%), 73% (41%-82%), and 50% (17%-88%), respectively. The lower back contributed to 11% (4%-22%) of time loss and 11% (5%-23%) of medical-attention injuries.

CONCLUSION

Dancers are vulnerable to LBP and LBI. The use of definitions that are sensitive to the complexity of LBP and LBI would facilitate improved understanding of the problem within dance, inform health care strategies, and allow for monitoring LBP-specific intervention outcomes. J Orthop Sports Phys Ther 2019;49(4):239-252. Epub 18 Jan 2019. doi:10.2519/jospt.2019.8609.

Immediate effects of ultrasound-guided percutaneous neuromodulation versus physical exercise on performance of the flexor hallucis longus muscle in professional dancers: a randomised clinical trial

Background:

Ultrasound-guided percutaneous neuromodulation (US-guided PNM) is a minimally invasive intervention. This technique consists of the application of percutaneous electrical stimulation (PES) through an acupuncture needle-like electrode that is placed in close proximity to the nerve or motor point of the target muscle under ultrasound guidance.

Objective:

To examine the immediate effects of a stretching exercise, an eccentric exercise and US-guided PNM on the performance of the flexor hallucis longus (FHL) muscle in young dancers.

Methods:

Randomised clinical trial. A total of 45 dancers were divided into three groups: Stretching group, Eccentric group and PNM group. The following performance parameters were assessed: range of motion (ROM) of the first metatarsophalangeal joint, balance test and unilateral heel raise fatigue test.

Results:

There were no differences between these groups in baseline measurements; at the end of the study, mean balance and endurance values were only significantly higher for the PNM group compared to the Stretching (p = 0.007 and p < 0.001, respectively) and Eccentric groups (p = 0.003 and p < 0.001, respectively). The effect sizes were large for the balance (d = 0.8) and endurance (d = 1.83) tests in the PNM group. Both the Stretching and Eccentric groups exhibited improvements in ROM compared to their baseline values (p = 0.009 and p = 0.004, respectively), whereas there was no significant temporal improvement noted for the PNM group. The effect sizes with respect to ROM values were moderate for stretching (d = 0.6) and eccentric (d = 0.7) exercises.

Conclusion:

An isolated PES intervention provides a greater immediate increase in balance and muscular strength than an active stretching and eccentric exercise of the FHL muscle in young ballet dancers.

Dynamic Neuro-Cognitive Imagery (DNITM) Improves Developpé Performance, Kinematics, and Mental Imagery Ability in University-Level Dance Students

Dance requires optimal range-of-motion and cognitive abilities. Mental imagery is a recommended, yet under-researched, training method for enhancing both of these. This study investigated the effect of Dynamic Neuro-Cognitive Imagery (DNITM) training on developpé performance (measured by gesturing ankle height and self-reported observations) and kinematics (measured by hip and pelvic range-of-motion), as well as on dance imagery abilities. Thirty-four university-level dance students (M age = 19.70 ± 1.57) were measured performing three developpé tasks (i.e., 4 repetitions, 8 consecutive seconds hold, and single repetition) at three time-points (2 × pre-, 1 × post-intervention). Data were collected using three-dimensional motion capture, mental imagery questionnaires, and subjective reports. Following the DNITM intervention, significant increases (p < 0.01) were detected in gesturing ankle height, as well as in hip flexion and abduction range-of-motion, without significant changes in pelvic alignment. These gains were accompanied by self-reported decrease (p < 0.05) in level of difficulty experienced and significant improvements in kinesthetic (p < 0.05) and dance (p < 0.01) imagery abilities. This study provides evidence for the motor and non-motor benefits of DNITM training in university-level dance students.

The role of prediagnostic data in injury epidemiology in preprofessional dancers

INTRODUCTION

preprofessional dance training starts at very early ages, on a highly demanding environment placing students at significant risk for injury. Injury management and prevention are a matter of concern. Given the constant interchangeability of risk factors, identifying injury patterns may prove to be equally as important. Data looking back from the time of injury through context-specific approaches are missing.

OBJECTIVES

To identify activity-related injury patterns based on prediagnostic data.

METHODS

Prospective, non-randomized, observational study, over a 3 years period on a full-time preprofessional dance school featuring both gender students aged 9-21 years old. Non-parametric statistics were used.

RESULTS

A total of 625 dance injury records from 209 students, n = 68 males and n = 141 females, were analyzed. Season injury risk probability was identified, proving different for each skill level (SkL). Multiple individual injuries revealed a trend toward prevalence rates in advanced level, while index injuries incidence becomes more noticeable in entry level students. Overall incidence rates had no significant differences within SkL. Anatomical location was in line with previous research, although differences were found between gender and SkL. Most injuries occurred in classes, with jumps standing out as the main motor action associated with injury symptoms of gradual onset mechanism.

CONCLUSION

Dance injuries happen because of dance practice. Knowing the context of injury history from the injured dancer perspective is determinant for management and prevention. prediagnostic data are an umbrella term encompassing several aspects of injury background and represents fertile ground for research. Context-specific methodological approaches are recommended.

Differences in lower limb biomechanics between ballet dancers and non-dancers during functional landing tasks

OBJECTIVES

To determine the differences in the lower limb landing biomechanics of adolescent ballet dancers compared to non-dancers when performing a hop and a stop jump task.

DESIGN

Cross-sectional.

SETTING

Laboratory.

PARTICIPANTS

Thirteen adolescent female ballet dancers (11.8 ± 1.1 years) and 17 non-dancers (10.9 ± 0.8 years) performed hop and stop jump tasks.

MAIN OUTCOME MEASURES

Vertical ground reaction force, and three-dimensional ankle, knee and hip joint angles and moments during the landing phase.

RESULTS

Dancers displayed greater sagittal plane joint excursions during the hop and stop jump at the ankle (mean difference = 22.0°, P < 0.001, 14.8°, P < 0.001 respectively), knee (mean difference = 18.1°, P = 0.001, 9.8°, P = 0.002 respectively) and hip (stop jump task; mean difference = 8.3°, P = 0.008). Dancers displayed a larger hip extensor moment compared to non-dancers (P < 0.001) during the stop jump task only. Dancers also took longer to reach peak vGRF and jumped three times higher than non-dancers (P < 0.001) during the stop jump task. No difference in peak vGRF between groups was displayed for either task.

CONCLUSIONS

Adolescent dancers demonstrate a transfer of landing technique to non-ballet specific tasks, reflective of the greater jump height and sagittal plane joint excursions. This landing strategy may be associated with the low rate of non-contact ACL injuries in female dancers.

Foot and ankle joint movements of dancers and non-dancers: a comparative study

Ballerinas use their ankle joints more extremely and sustain injuries on the ankle joint more frequently than non-dancers. Therefore, the ankle movement of dancers is important and should be studied to prevent injuries. Measuring ankle joint range of motion (ROM) using radiographs could demonstrate the contribution to motion of each joint. The aim of this study was to analyse and compare ankle joint movements and the ratio of each joint's contribution during movement between dancers and non-dancers, using radiographic images. Dancers have lower dorsiflexion (26.7 ± 6.2°), higher plantarflexion (74.3 ± 7.1°) and higher total (101.1 ± 10.8°) ROMs than non-dancers (33.9 ± 7.0°, 57.2 ± 6.8° and 91.1 ± 9.3°, respectively) (p < 0.05). Although the ROMs were different between the two groups, the ratios of each joint movement were similar between these two groups, in all movements. Regarding total movement, the movement ratio of the talocrural joint was almost 70% and other joints accounted for almost 30% of the movement role in both dancers and non-dancers. Therefore, the differences in ROM between dancers and non-dancers were not a result of a specific joint movement but of all the relevant joints' collaborative movement.

Risk factors for musculoskeletal injury in elite pre-professional modern dancers: A prospective cohort prognostic study

OBJECTIVES

To examine risk factors for injury in pre-professional modern dancers.

DESIGN

With prospectively designed screening and injury surveillance, we evaluated four risk factors as categorical predictors of injury: i) hypermobility; ii) dance technique motor-control; iii) muscle tightness; iv) previous injury. Screening and injury data of 180 students enrolled in a university modern dance program were reviewed over 4-yrs of training. Dancers were divided into 3-groups based on predictor scores. Dance exposure was based on hours of technique classes/wk. Negative binomial log-linear analyses were conducted with the four predictors, p < 0.05.

RESULTS

Dancers with low and high Beighton scores were 1.43 and 1.22 times more likely to sustain injury than dancers with mid-range scores (p ≤ 0.03). Dancers with better technique (low or medium scores) were 0.86 and 0.63 times less likely to sustain injury (p = 0.013 and p < 0.001) compared to those with poor technique. Dancers with one or 2-4 tight muscles were 2.7 and 4.0 times more likely to sustain injury (p ≤ 0.046). Dancers who sustained 2-4 injuries in the previous year were 1.38 times more likely to sustain subsequent injury (p < 0.001).

CONCLUSIONS

This contributes new information on the value of preseason screening. Dancers with these risk factors may benefit from prevention programs.

The Influence of Injury Definition on Injury Burden in Preprofessional Ballet and Contemporary Dancers

Study Design Cohort study. Background Multiple operational definitions of injury exist in dance research. The influence that these different injury definitions have on epidemiological estimations of injury burden among dancers warrants investigation. Objective To describe the influence of injury definition on injury prevalence, incidence, and severity in preprofessional ballet and contemporary dancers. Methods Dancers registered in full-time preprofessional ballet (n = 85; 77 female; median age, 15 years; range, 11-19 years) and contemporary (n = 60; 58 female; median age, 19 years; range, 17-30 years) training completed weekly online questionnaires (modified Oslo Sports Trauma Research Centre questionnaire on health problems) using 3 injury definitions: (1) time loss (unable to complete 1 or more classes/rehearsals/performances for 1 or more days beyond onset), (2) medical attention, and (3) any complaint. Physical therapists completed injury report forms to capture dance-related medical attention and time-loss injuries. Percent agreement between injury registration methods was estimated. Injury prevalence (seasonal proportion of dancers injured), incidence rates (count of new injuries per 1000 dance-exposure hours), and severity (total days lost) were examined across each definition, registration method, and dance style. Results Questionnaire response rate was 99%. Agreement between registration methods ranged between 59% (time loss) and 74% (injury location). Depending on definition, registration, and dance style, injury prevalence ranged between 9.4% (95% confidence interval [CI]: 4.1%, 17.7%; time loss) and 82.4% (95% CI: 72.5%, 89.8%; any complaint), incidence rates between 0.1 (95% CI: 0.03, 0.2; time loss) and 4.9 (95% CI: 4.1, 5.8; any complaint) injuries per 1000 dance-hours, and days lost between 111 and 588 days. Conclusion Time-loss and medical-attention injury definitions underestimate the injury burden in preprofessional dancers. Accordingly, injury surveillance methodologies should consider more inclusive injury definitions. J Orthop Sports Phys Ther 2018;48(3):185-193. Epub 13 Dec 2017. doi:10.2519/jospt.2018.7542 Level of Evidence Symptom prevalence study, level 1b.

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).

Hip and Groin Injuries in Dancers: A Systematic Review

CONTEXT

Injury data on hip and groin injuries vary, and these injuries are often misrepresented or overlooked for more commonly seen injuries, such as those to the foot and ankle.

OBJECTIVE

To provide a systematic review of the injury rates of hip and groin pathology in dancers and look to establish a better understanding of the occurrence of hip and groin injuries in the dancer population.

DATA SOURCES

A literature search was performed using PubMed and CINAHL databases for articles published between 2000 and 2016.

STUDY SELECTION

Inclusion criteria consisted of (1) documentation of the number of hip and/or groin injuries, (2) study population consisting of dancers whose training included some level of ballet, and (3) studies of levels 1 through 3 evidence.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 3.

DATA EXTRACTION

A single reviewer identified studies that met the inclusion criteria. The number of overall injuries, hip/groin injuries, study participants, injured participants, training hours per week, mean age of study group, injury definition, injury reporting method, and study time frame were extracted.

RESULTS

Thirteen unique studies were included in the descriptive analysis. Of the 2001 dancers included in this study, 3527 musculoskeletal injuries were seen in 1553 dancers. Of these, 345 injuries were localized to the hip and groin region (overall rate, 17.2%). An incidence rate of 0.09 hip and groin injuries per 1000 dance-hours was seen in the selected cohort studies. Of 462 professional dancers, 128 hip/groin injuries were recorded, for an injury rate of 27.7%. Of the 1539 student dancers, 217 hip/groin injuries were recorded, for an injury rate of 14.1% ( P < 0.01).

CONCLUSION

Data on hip and groin injuries have many limitations. However, these injuries represent an important health issue for dancers of all skill levels, encompassing 17.2% of musculoskeletal injuries seen in dancers. An increasing rate of hip/groin injuries is seen in professional dancers compared with students.

Occupational Health and the Performing Arts: An Introduction

OBJECTIVE

Workplace hazards in the performing arts cause injuries, disabilities, and deaths every year. Occupational health professionals are familiar with most of these hazards and are particularly qualified to contribute to efforts to reduce them. This article reviews current health issues in the performing arts and highlights opportunities for occupational health contributions.

METHODS

Recognized experts in performing arts medicine were consulted and articles illustrating performing arts health issues were reviewed. Literature sources included medical databases, unindexed art-health publications, and popular press articles.

RESULTS

Resources discussing hazards and health issues in theater, dance, voice, and instrumental musicians were located and reviewed.

CONCLUSIONS

Treatment providers have a history of involvement with segments of the performing arts. The occupational health approach to workplace health issues can effectively complement these efforts. Sources of further information on performing arts health concerns are available.

Overuse Injuries in Professional Ballet: Influence of Age and Years of Professional Practice

Background:

In spite of the high rate of overuse injuries in ballet dancers, no studies have investigated the prevalence of overuse injuries in professional dancers by providing specific diagnoses and details on the differences in the injuries sustained as a function of age and/or years of professional practice.

Hypothesis:

Overuse injuries are the most prevalent injuries in ballet dancers. Professional ballet dancers suffer different types of injuries depending on their age and years of professional practice.

Study Design:

Descriptive epidemiology study.

Methods:

This descriptive epidemiological study was carried out between January 1, 2005, and October 10, 2010, regarding injuries sustained by professional dancers belonging to the major Spanish ballet companies practicing classical, neoclassical, contemporary, and Spanish dance. The sample was distributed into 3 different groups according to age and years of professional practice. Data were obtained from the specialized medical care the dancers received from the Trauma and Orthopaedic Surgery Service at Fremap in Madrid. The dependent variable was the study of the injury.

Results:

A total of 486 injuries were identified over the study period, with overuse injuries being the most common etiology (P < .0001); these injuries were especially prevalent in junior professional dancers practicing classical ballet and veteran dancers practicing contemporary ballet (P = .01). Specifically, among other findings, stress fractures of the base of the second metatarsal (P = .03), patellofemoral syndrome, and os trigonum syndrome were more prevalent among junior professionals (P = .04); chondral injury of the knee in senior professionals (P = .04); and cervical disc disease in dancers of intermediate age and level of experience.

Conclusion:

Overall, overuse injuries were more prevalent in younger professionals, especially in women. This finding was especially true for the more technical ballet disciplines. On the other hand, in the athletic ballet disciplines, overuse lesions occurred mainly in the more senior professionals.

Clinical Relevance:

This study provides specific clinical diagnoses obtained through physical examination as well as details on the different injury types sustained as a function of age and/or years of professional practice, an important aspect for ballet and sports practice in general.

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.

Life history and point prevalence of low back pain in pre-professional and professional dancers

OBJECTIVES

To investigate lifetime history and point prevalence of low back pain (LBP) in pre-professional and professional dancers and to identify any demographic or physical factors associated with LBP in dancers.

DESIGN

Cross-sectional study.

SETTING

One pre-professional ballet school, two pre-professional university dance programs, and a professional nationally touring ballet company.

PARTICIPANTS

Male and female classical ballet and contemporary dancers aged 12 years old and above.

MAIN OUTCOME MEASURES

Lifetime history and point prevalence of LBP.

RESULTS

A total of 110 (n = 19 male) dancers (mean (SD) 17.8 (2.9) years old) participated in the study, which represented 50% of the population invited to participate. A 74% lifetime prevalence of LBP was reported by dancers. Point and 12 month prevalence were 24 and 64%, respectively. No significant association was observed between LBP and any demographic or physical variables.

CONCLUSION

Pre-professional and professional dancers have an increased vulnerability to LBP. The development of LBP within this population is complex and may not be associated with individual factors measured in this study.