Injury patterns in young, non-professional dancers

Patellofemoral pain and musculoskeletal features in young pre- and post-pubertal female dancers

The aim of this study was to examine associations between patellofemoral pain (PFP) and musculoskeletal features (such as tendon structure and bone properties) in young (pre- and post-pubertal) female dancers. A total of 49 dancers participated in this study (mean age 13.6 ± 2.9; weight 47.0 ± 13.2; height 153.7 ± 12.9 and body mass index (BMI) 19.4 ± 3.1) and were assessed for the following factors: dance background and Tanner stage through interviews; ultrasonography assessments of bone properties and patellar tendon structure through ultrasonographic tissue characterization and quantitative ultrasound, respectively; and anthropometric measurements, muscle strength, range of motion (ROM), hypermobility and PFP through physical examinations. PFP was found in 49% of the participants. Post-pubertal dancers with no-PFP were found to have greater muscle strength, greater radial and tibial properties, and better tendon structure compared to pre-pubertal dancers with PFP and compared to pre-pubertal dancers with no-PFP [F(2, 41) = 18.64, p < .001; F(2, 41) = 20.46, p < .001; F(2, 41) = 33.06, p < .001; and, F(2, 41) = 6.02, p = .007, respectively]. Logistic regression showed that tibial bone properties and range of movement (ROM) in hip external rotation were significantly associated with PFP [odds ratio (OR) = .889 and OR = 2.653, respectively; Cox & Snell R2 = .701]. The study revealed a high prevalence of PFP among young dancers, with low bone properties and hyperjoint ROM emerging as the main factors that are related to PFP. These findings should be addressed by medical teams, athletic trainers, and dance teachers regarding the need for implementing modifications to dance training programmes and injury-prevention strategies in young pre-pubertal dancers.

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.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Prevalence of ankle instability in performers of Chinese classical dance: a cross-sectional study of 105 Chinese dancers

Objectives

Foot and ankle injuries are commonly seen in dancers, yet limited studies exist on the injury prevalence of performers of Chinese classical dance. This study aims to determine and assess the prevalence of chronic ankle instability (CAI) in Chinese dancers and correlate the impact of CAI with foot function.

Methods

This is a cross-sectional study of 105 Chinese dancers. CAI was assessed using the Cumberland Ankle Instability Tool and foot function via the Foot and Ankle Outcome Score (FAOS). Both self-reported assessment tools were distributed online between January and February 2021. Subjects were divided into CAI and healthy groups to observe any correlations in demographics, training hours and foot function.

Results

CAI was seen in 28% of Chinese dancers, with most being unilateral instability. The number of training hours, level of expertise, occupation, gender and age showed no statistical significance with CAI. The FAOS showed that subjects with CAI had significantly greater pain and poorer quality of life.

Discussion and conclusion

CAI is a problem affecting 28% of performers of Chinese dance. Future research should investigate the ankle biomechanics in Chinese dance and specific risk factors for CAI to formulate strategies to prevent ankle injuries in Chinese dancers.

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.

Development of Muscle-Tendon Adaptation in Preadolescent Gymnasts and Untrained Peers: A 12-Month Longitudinal Study

PURPOSE

The current study investigated the effects of long-term athletic training on the development of the triceps surae muscle-tendon unit in preadolescence.

METHODS

Eleven preadolescent untrained children and a group of 21 artistic gymnastics athletes of similar age (9 ± 1.7 yr) and maturity (Tanner stages I and II) participated in the study. The measurements were conducted every 3 months for 1 yr, and training volume and duration of the athletes were documented. Plantar flexor muscle strength, Achilles tendon stiffness, maximum tendon strain, and gastrocnemius medialis morphometrics were measured by integrating kinematics, ultrasonography, and dynamometry. A linear mixed-effects model was used to analyze the investigated parameters.

RESULTS

We found greater muscle strength (P < 0.001) in athletes compared with nonathletes but no differences in Achilles tendon stiffness (P = 0.252), indicating a training-induced imbalanced adaptation of muscle strength and tendon stiffness in preadolescent athletes. Although pennation angle (P = 0.490), thickness (P = 0.917), and fascicle length (P = 0.667) did not differ between groups, we found higher fluctuations in pennation angle and muscle strength over 1 yr in athletes. The imbalanced adaptation of muscle strength and tendon stiffness together with greater fluctuations of muscle strength resulted in greater tendon strain fluctuations over 1 yr (P = 0.017) and a higher frequency of athletes with high-level tendon strain (≥9%) compared with nonathletes.

CONCLUSIONS

The findings indicate an increased mechanical demand for the tendon in preadolescent athletes that could have implications for the risk of tendon overuse injury. Therefore, we recommend the implementation of individual training approaches to preserve a balanced adaptation within the triceps surae muscle-tendon unit in preadolescent athletes.

Novel Quantitative Ultrasonic Analysis of Patellar Tendon in Collegiate Athlete Following Bilateral Debridement: A Case Report

An NCAA Division I female basketball athlete (20 years, 190.5 cm, 87 kg) suffered from chronic tendinopathy. After failed conservative treatments, the athlete underwent bilateral open patellar debridement surgery. Pain and dysfunction were assessed via the Victorian Institute of Sport-P (VISA-P) with concurrently collected B-mode ultrasound images of the patellar tendon throughout a 12 month rehabilitation. Peak spatial frequency radius (PSFR), a quantitative ultrasound parameter previously shown to correlate to collagen organization, was compared to changes in VISA-P scores. An overall increase in PSFR values across 0, 30, 60, and 90° of knee flexion were observed throughout recovery. Despite increased PSFR and returning to sport, the athlete still reported significant pain. This level 3 exploration case report provides novel insight into ultrasonically-measured structural changes of the patellar tendon following surgery and during rehabilitation of an athlete suffering from chronic tendinopathy. Perceived pain measurements were not necessarily related to structural adaptations.

Sagittal Integral Morphotype of Female Classical Ballet Dancers and Predictors of Sciatica and Low Back Pain

The aims of this study were to describe the sagittal integral morphotype (SIM) of classical ballet (CB) dancers, and to establish predictor factors and their cut off values for high risk of experiencing sciatica or low back pain (LBP). This retrospective cohort study was performed in 33 female professional CB dancers. Data related to anthropometric parameters, CB dance experience, sciatica or LBP history, and sagittal spine curvatures were collected. A binary logistic regression and receiver-operating characteristic analysis were performed. The main spine misalignments observed in the SIM of CB dancers were thoracic functional hyperkyphosis, hypomobile kyphosis, and hypokyphosis, and those for the lumbar curvature were hyperlordotic attitude and functional hyperkyphosis. The lumbar curvature in slump sitting and trunk forward bending positions, together with the stature, were significant predictor factors of sciatica history, while the years of dance experience was a significant predictor factor of LBP history. The cut off values analysis revealed that dancers with a stature of 161 cm or less, and those with 14 years of experience or more, have a greater probability of experiencing sciatica or LBP history, respectively.

Predicting Injury Status in Adolescent Dancers Involved in Different Dance Styles: A Prospective Study

The positive effects of dance on health indices in youth are widely recognized, but participation in dance is accompanied with a certain risk of injury. This prospective study aimed to investigate injury occurrence and to evaluate the possible influences of specific predictors on the occurrence of musculoskeletal problems and injuries in adolescent dancers. Participants were 126 dancers (21 males; 11–18 years), who were competitors in the urban dance, rock and roll, and standard/Latin dance genres. Predictors included sociodemographic factors, anthropometric/body build indices, sport (dance) factors, and dynamic balance. The outcome variable was injury status, and this was evaluated by the Oslo Sports Trauma Research Centre Overuse Injury Questionnaire (OSTRC). Predictors were evaluated at baseline, and outcomes were continuously monitored during the study period of 3 months. During the study course, 53% of dancers reported the occurrence of a musculoskeletal problem/injury, and dancers suffered from an average of 0.72 injuries over the study period (95% CI: 0.28–1.41), giving a yearly injury rate of 280%. Gender and dance styles were not significantly related to the occurrence of injury. Higher risk for injury was evidenced in older and more experienced dancers. Dynamic balance, as measured by the Star Excursion Balance Test (SEBT), was a significant protective factor of injury occurrence, irrespective of age/experience in dance. Knowing the simplicity and applicability of the SEBT, continuous monitoring of dynamic balance in adolescent dancers is encouraged. In order to prevent the occurrence of musculoskeletal problems/injuries in youth dancers, we suggest the incorporation of specific interventions aimed at improving dynamic balance.

Special Considerations for Growing Dancers

Care of young dancers requires a unique approach during a critical time of growth and development. Young dancers' well-being depends on factors including sleep, mental health, growth-associated musculoskeletal imbalances, and nutrition. Puberty is a particularly important time for young dancers. It coincides with an increased commitment to their art form and physical/psychosocial changes. It is imperative for practitioners to understand these various factors in order to optimize young dancers' health and allow them to safely train and perform.

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.

Can young dancers skip/recover from patellofemoral pain? A two-year follow-up

Aiming to follow the prevalence of patellofemoral pain (PFP) among young dancers over 2-years, and to assess the prevalence of re-injured/recovered dancers; 67 dancers (aged 12.8 ± 0.5) were screened for PFP at baseline, 65 dancers at 1^st follow-up and 51 dancers at 2^nd follow-up. All dancers (46) that took part in all the 3 screenings had at least one episode of PFP along the screenings. No dancers recovered in the 1^st follow-up, yet 40.5% of the dancers with PFP at the 1^st follow-up recovered in the 2^nd follow-up. Along the 3 screenings, 23.9%, 34.8%, and 41.3% of the dancers had 1,2 or 3 PFP episodes, respectively. None of the dancers skipped PFP along the 3 screenings. A high prevalence of dancers had sustained PFP along the 2 follow-ups, with low recovery rate. Dancers and teachers should be alert to the need for devising modifications of training and injury prevention strategies from young age.

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.

Unilateral and bilateral patellofemoral pain in young female dancers: Associated factors

Aiming to evaluate the prevalence of unilateral/bilateral patellofemoral pain (PFP) among young dancers, and to investigate whether different factors are associated with PFP in young dancers, 132 dancers aged 12-14 years were assessed for PFP. Anthropometric parameters, proprioception ability, dynamic postural balance (DPB), and muscle strength were measured. PFP was found in 64.1% of the dancers. No significant differences in the prevalence of dancers with no, unilateral, or bilateral PFP at different ages were found. Significant age effects were found for anthropometric and developmental measurements, and for intensity of training. PFP effect was found for DPB asymmetry, ankle proprioception, and leg-length %height. A higher hip abductor/adductor ratio was associated with PFP in 14-year-old dancers. Binomial logistic regression showed that increased number of hours per day (h/day) and decreased number of hours per week (h/week), low proprioception scores, greater leg length as %height, and more anterior DPB asymmetry were significant predictors of PFP. In conclusion: unilateral/bilateral PFP is common among young dancers. Body morphology, reduced ankle proprioception ability, DPB asymmetry, and increased h/day of practice are associated with PFP. Dance teachers should start monitoring the impact of training and implement injury modification/prevention strategies when their students are at a young age.

Ankle Injuries in Dancers

The term dance encompasses a broad range of different styles; much of the orthopaedic literature has focused on ballet dancers. Injury is common in dancers at all levels, and many serious dancers sustain multiple injuries as they progress through their career. Foot and ankle injuries are among the most common injuries experienced by dancers. These injuries include those that are specific to dancers because of the unique physical maneuvers required to effectively perform, but they can also include common injuries that may require relatively different treatment because of the physical demands of the dancer. Os trigonum syndrome and flexor hallucis longus tenosynovitis generally fall into the former category as they are injuries that are more prevalent in dancers due to the extreme plantarflexion involved in dancing, especially ballet, and the relative demand placed on the toe flexors, most notably the flexor hallucis longus. On the other hand, anterior ankle impingement occurs both in dancers and in the general public. In many cases, a team approach to treatment with knowledgeable physical therapists can obviate the need for surgical treatment. If surgical treatment proves necessary, good results can be achieved with sound surgical technique and a well thought-out rehabilitation program.

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

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

The 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.

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

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

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Should Ballet Dancers Vary Postures and Underfoot Surfaces When Practicing Postural Balance?

BACKGROUND

Postural balance (PB) is an important component skill for professional dancers. However, the effects of different types of postures and different underfoot surfaces on PB have not adequately been addressed.

PURPOSE

The main aim of this study was to investigate the effect of different conditions of footwear, surfaces, and standing positions on static and dynamic PB ability of young ballet dancers.

METHODS

A total of 36 male and female young professional ballet dancers (aged 14-19 years) completed static and dynamic balance testing, measured by head and lumbar accelerometers, while standing on one leg in the turnout position, under six different conditions: (1) "relaxed" posture; (2) "ballet" posture; (3) barefoot; (4) ballet shoes with textured insoles; (5) barefoot on a textured mat; and (6) barefoot on a spiky mat.

RESULTS

A condition effect was found for static and dynamic PB. Static PB was reduced when dancers stood in the ballet posture compared with standing in the relaxed posture and when standing on a textured mat and on a spiky mat (p < .05), and static PB in the relaxed posture was significantly better than PB in all the other five conditions tested. Dynamic PB was significantly better while standing in ballet shoes with textured insoles and when standing on a spiky mat compared with all other conditions (p < .05).

CONCLUSIONS

The practical implications derived from this study are that both male and female dancers should try to be relaxed in their postural muscles when practicing a ballet aligned position, including dance practice on different types of floors and on different types of textured/spiky materials may result in skill transfer to practice on normal floor surfaces, and both static and dynamic PB exercises should be assessed and generalized into practical dance routines.

At What Age Do Children and Adolescents Develop Lower Limb Tendon Pathology or Tendinopathy? A Systematic Review and Meta-analysis

BACKGROUND

Tendon pathology and tendinopathy have been reported in children and adolescents; however, the age at onset and prevalence of the conditions have not been examined systematically.

OBJECTIVE

To examine the prevalence of lower limb tendon pathology and tendinopathy in children and adolescents, and the factors associated with these conditions in this population.

METHODS

Six databases were searched (MEDLINE, the Cochrane Central Register of Controlled Trials, Embase, Scopus, the Web of Science and the Allied and Complementary Medicine Database). Studies were included if the prevalence of lower limb tendon pathology and/or tendinopathy were reported in humans under the age of 18 years. Studies were divided according to the method of diagnosis (physical examination, ultrasound or a questionnaire) and further divided into studies that reported prevalence data by tendon [reported two data points (right and left) for each participant] and those that reported prevalence data for each participant [reporting one data point (right or left) per participant].

RESULTS

Seventeen studies met the inclusion criteria. Lower limb tendinopathy prevalence (presence of pain and dysfunction) ranged between 8.2 and 33.3%, and increased in prevalence as age increased up to 18 years. The odds ratio for studies reporting tendinopathy by tendon was 0.37 (95% confidence interval 0.20-0.69) in favour of boys presenting with tendinopathy. Study aims and reporting methods were heterogeneous.

CONCLUSIONS

The age at onset of lower limb tendinopathy in children and adolescents has not been widely studied. This systematic review found that tendinopathy is present in children and adolescents, and increases in prevalence with age up to 18 years. Male sex is significantly associated with tendinopathy in studies that report tendinopathy by tendon.

Critical review on the socio-economic impact of tendinopathy

There are currently no studies that determine the total burden that tendinopathy places on patients and society. A systematic search was conducted to understand the impact of tendinopathy. It demonstrated that the current prevalence is underestimated, particularly in active populations, such as athletes and workers. Search results demonstrate that due to the high prevalence, impact on patients' daily lives and the economic impact due to work-loss, treatments are significantly higher than currently observed. A well-accepted definition by medical professionals and the public will improve documentation and increase awareness, in order to better tackle the disease burden.

Injuries in female dancers aged 8 to 16 years

CONTEXT

Most studies of injured dancers have been carried out on professional adult dancers; data on young, nonprofessional injured dancers are sparse.

OBJECTIVE

To identify the types of injuries sustained by recreational dancers and to examine their association with age, joint range of motion, body structure, age at menarche, presence of anatomic anomalies, and physical burden (i.e., practice hours en pointe).

DESIGN

Descriptive epidemiology study.

SETTING

The Israel Performing Arts Medicine Center, Tel Aviv.

PATIENTS OR OTHER PARTICIPANTS

A total of 569 injured female dancers, aged 8 to 16 years.

MAIN OUTCOME MEASURE(S)

Dependent variables were 61 types of current injuries that were later classified into 4 major categories: knee injuries, foot and ankle tendinopathy, back injuries, and other injuries. Independent variables were age, joint range of motion, body size and shape, age at menarche, anatomic anomalies, and dance discipline (e.g., hours of practice per week en pointe).

RESULTS

At least 1 previous injury had been sustained by 42.4% of the dancers. The most common injuries involved the knee (40.4%), followed by other injuries (23.4%). The relative frequency of back injuries and tendinopathy decreased with age, whereas knee injuries increased. Types of injuries were significantly associated with ankle plantar flexion, hip external rotation, hip abduction, and knee flexion. Multinomial regression analysis revealed only 3 predictive variables (with other as baseline), all for back injury: scoliosis, age, and hip external rotation.

CONCLUSIONS

Joint range of motion and scoliosis may signal the potential for future injury. Young dancers (less than 10 years of age) should not be exposed to overload (especially of the back) or extensive stretching exercises.

Paratenonitis of the foot and ankle in young female dancers

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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