Journal of Dance Medicine & Science最新文献

Introduction: Ballet dancing is driven by goals of artistic performance that depend on aesthetic standards. These standards involve maintaining a slim and muscular physique. Therefore, dancers tend to adopt eating behaviors that may have long-term consequences for their health and performance. This study aims to explore ballet dancers' perceptions of their dietary behaviors. Method: This study employed a qualitative approach, utilizing semi-structured interviews conducted via videoconference. Recruitment was carried out on social media in January 2023. Interviews were analyzed through reflexive thematic analysis. Each interview was coded using an inductive approach. Categories were grouped into sub-themes and themes. Participant citations were then translated. Results: Eleven interviews were conducted with professional ballerina dancers from various Operas in France and Monaco. Analysis generated three themes. Firstly, dancers must meet specific ballet standards instilled in them by both instructors and peers. Dance instructors were perceived as authority figures, and their words about their students' physical appearance during puberty often carried stressful memories. Secondly, our participants discussed their relationship to food. To match the ideal ballerina's appearance, dancers recounted adopting unhealthy eating behaviors. Thirdly, once in a ballet company, dancers recalled gaining maturity and knowledge, which helped them realize the consequences of these negative behaviors. They became more concerned about their health and adapted their diets. Individual characteristics, personal reactions to instructors' demands, and the influence of significant others influenced their eating behaviors. Our participants voiced a desire for attitudes to change regarding ballet standards. They wished for more medical follow-up concerning physical and mental health. Conclusion: When it comes to diet, professional ballet dancers should be considered not just as artists, but also as elite athletes. Eating behaviors play a fundamental role in an athlete's performance and well-being, as they help meet nutritional needs in the context of high athletic fueling demands.

Introduction: Turnout, or external rotation, is a fundamental movement pattern in dance and has been associated with injury risk. While previous research has examined the relationship between turnout and range of motion (ROM) while other contributing factors such as strength and movement competency have been largely overlooked. This study aimed to explore the relationships between functional turnout measurements and movement competency screen (MCS) scores, passive hip external rotation (PER) and external rotation strength in collegiate dancers. Understanding these relationships is crucial for optimizing training and reducing injury risk in dancers. Methods: Twenty-one undergraduate dance majors participated in a cross-sectional study assessing PER, strength, movement competency (MCS) and turnout in a single session. Turnout was assessed statically (Static Functional Turnout, SFT) and dynamically (Dynamic Functional Turnout, DFT), in both first and fifth positions. Data were analyzed using IBM SPSS Statistics v27.0.1.0, with Pearson correlations used to examine the relationships between variables. Results: No statistically significant relationships were found between individual turnout measurements and MCS scores. Most participants (n = 18) exhibited greater SFT than their available PER, suggesting that turnout was achieved through movement at joints other than the hips. These dancers had lower PER and hip external rotation strength compared to those whose SFT was less than their PER. The extent to which dancers exceeded their PER during SFT had a moderate to good negative correlation with MCS scores (R = -.555, P = .017). This suggests that dancers who generate turnout beyond their passive hip mobility have lower movement competency. Conclusion: Turnout execution in dancers varies widely and does not consistently correlate with hip external rotation strength, ROM, or movement competency scores. However, dancers who exceed their available PER during the SFT demonstrate lower movement competency, suggesting that motor control may be an important factor in turnout execution.

Introduction: There are similarities in physical and psychological demands, but differences in working conditions between professional freelance and company dancers. The purpose of this study is to examine the work ability of professional dancers working in both of these fields and to analyze influencing factors associated with each work model.

Methods: A partially standardized survey was used to collect sociodemographic and dance-specific data. Work Ability Index (WAI) scores were also collected. The sample consisted of 247 participants (172 freelance and 75 company dancers). Differences between the subgroups were analyzed using Analyses of Variance (ANOVA), parametric and non-parametric tests. Factors impacting the WAI score(s) were determined by the employment of several generalized linear regression models.

Results: The sample shows moderate to good work ability, and statistical analysis revealed no significant difference between professional freelance and company dancers (P = .984). There are significant differences between the subgroups of professional dancers in terms of age (P < .01), ethnicity (P < .001), predominant dance style (P < .001), weekly training hours (P < .001), number of workplaces (P < .001), and distribution of work content (P < .001). Regression shows that negative factors for WAI are female (RF = -2.438, P < .1) and non-binary gender (RF = -7.822, P < .5) and increasing number of workplaces (RF = -1.125, P < .05). Positive factors include work in commercial (RF = 6.399, P < .01) and jazz dance (RF = 6.503, P < .01).

Conclusions: Professional freelance and company dancers generally demonstrate moderate to good work ability, which indicates that there is room to increase the proportion of those with very good work ability. Given that ability to work is influenced by multiple factors, special attention should be given to female and non-binary dancers, who are more likely to experience negative impacts on their work ability.

Objectives: Lower back pain (LBP) is a common issue among dancers across various styles. This study aims to investigate the 12-month prevalence, level of disability, duration and frequency of LBP episodes in a sample of dancers engaged in different dance styles. Additionally, it seeks to identify risk factors for low back pain, including dance style, sociodemographic factors, and psychosocial factors.

Methods: A survey was conducted via an online questionnaire utilizing www.SoSciSurvey.de. 77 dancers aged between 14 and 45 years, who danced at least 1 hour per week on average, were included. The sample comprised both recreational and professional dancers, exhibiting a wide range of workloads. Participants conveyed their sociodemographic Information, parameters related to their dancing and their 12-month prevalence of LBP including the duration and frequency of LBP episodes. To assess the degree of LBP induced disability, participants completed the Oswestry disability Index (ODI). A Chi-squared Test (Prevalence), Kruskal-Wallis Test (H-test), and Spearman correlation (confounders) were conducted.

Results: The 12-month prevalence of LBP in the cohort was high with 83.1%. The dance style did not have a statistically significant impact on the 12-month prevalence (P = .844) and the ODI (P = .065). Satisfaction with their own dance performance, coaching staff and the dance group, as well as heavy manual labor, smoking and psychological comorbidities were all statistically significantly correlated with at least 1 of the outcomes (P < .05).

Conclusion: Psychosocial factors, psychological comorbidities, and lifestyle factors such as occupation and smoking status impacted LBP. Dance style did not affect LBP significantly.

Aim: This study investigated how muscle activation and movement altered as a result of dorsiflexor and plantarflexor muscle fatigue in dancers during single-leg relevés.

Methods: 14 participants with current or recent experience in dance performed 10 single-leg relevés before and after a fatigue protocol at a set tempo of 46 beats per minute. The pre-fatigue and post-fatigue differences were assessed via surface electromyography of the lateral gastrocnemius, medial gastrocnemius, soleus, and tibialis anterior during the ascending and descending phases. Kinematic data was obtained and assessed using 3D motion capture technology.

Results: No significant differences in muscle activation occurred from pre-fatigue to post-fatigue during the ascending phase. However, there was a significant increase in activation during the descending phase in both the soleus (P = .020) and lateral gastrocnemius (P = .028). Additionally, there was a significant decrease in ankle range of motion (P = .004) and heel height achieved (P = .006) from pre-fatigue to post-fatigue. There was also a significant decrease in ankle dorsiflexion (P < .001) and plantarflexion (P = .014) post-fatigue.

Conclusion: Overall, ankle plantarflexor fatigue results in an inability to maintain movement despite increased muscle activation. Future research could support in validating the findings that dancers should limit working past or near fatigue, as it could lead to increased mechanical compensations which increase the risk of injury.

Introduction: Excessive contact forces on the hands during breaking can potentially cause a high injury incidence. Chair freeze is a basic posture unique to breaking; however, its effect on the hands remains unclear. Clarifying dancer-specific factors is essential for preventing trauma and overuse injuries. This study aimed to investigate the contact load and pressure on the hands during chair freeze and their determinants.

Methods: 15 professional breakers were recruited. The peak landed load per bodyweight and contact pressure were measured using thin-film pressure sensors in the chair freeze and handstand postures. The location of the highest pressure was also assessed. The following possible factors of load and pressure were assessed: age, height, weight, body mass index, hand axis, practice duration, and grip strength.

Results: Load per bodyweight and pressure were significantly higher in the chair freeze than in the handstand (0.69 bodyweight vs 0.47 bodyweight and 247.1 kPa vs 155.8 kPa; P < .0001 and P < .0001, respectively). In 14 of 15 dancers (93.3%), the highest pressure was concentrated on the radial side of the palm during chair freeze. Body height and weight were significantly correlated with load per bodyweight and pressure in chair freeze (ρ = 0.55, 0.57, 0.54, and 0.59; P = .036, .028, .038, and .020, respectively).

Conclusion: Load per bodyweight and pressure on the landed hand was 1.5- to 1.6-fold higher during the chair freeze than during the handstand, concentrating on the radial side of the palm. Dancers' body size was associated with the contact force on the hand in the chair freeze.

Introduction: In conjunction with medication, exercise is key for managing Parkinson disease (PD) related motor symptoms. Barre is an exercise modality that combines elements of classical ballet with strength training, involving high repetitions of low impact movements. Barre is accessible and may address documented barriers to exercise for people with PD such as fear of falling, lack of enjoyment, and lack of social support. To our knowledge, there is no previous literature on the effects of barre for PD. Therefore, this study aims to test the feasibility and acceptability of a novel barre exercise intervention. Methods: Individuals with mild to moderate PD were recruited to participate in a barre exercise class. The intervention consisted of twice-weekly, 45-minute group exercise classes for 12 weeks. Feasibility benchmarks included attendance, retention, and acceptability. Balance, gait, and functional strength assessments were carried out pre- and post-intervention to explore preliminary motor trends. Participants also completed a quality of life survey and a qualitative exit interview. Results: Eleven individuals completed the intervention. All three feasibility benchmarks were met. Participants had high attendance (70-100% of classes offered), high retention (84.6%), and reported that the class quality was excellent and generally met their needs. While most motor outcomes changed little pre- to post-intervention, gait outcomes (speed, distance on 2MWT) did improve. Exit interview themes surrounding what participants liked best about the program included comradery, support, and that the class was specific to PD, with 82% of participants indicating that they would re-enroll if the class was offered in a community setting. Conclusion: Engaging in barre exercise may be a safe, feasible way to meet exercise guidelines for PD. Future controlled studies should explore the clinical efficacy of barre for improving balance, gait, and functional strength in larger samples.

Introduction: There is an increased injury risk during pointe training if dance students are not physically or technically prepared. The objective of this study was to find consensus between dance experts pertaining to the most reliable screening protocols when determining pointe readiness in young adolescent female dance students. Methods: Dance experts (10+ years of professional dance (pointe) experience/teaching pointe experience/clinician to dancers), were recruited through multiple dance teacher/science groups on social media. The Delphi method was utilized via Online Surveys and distributed in rounds until consensus was found. Questions were created, and subsequent rounds were devised based on analyzed data from the previous round. Descriptive and thematic analysis was used to collate, rank, and analyze data. Consensus was determined at 60% agreement between the dance experts' answers. Results and discussion: Fifteen dance experts completed Round 3 with 80% consensus. The most important physical attributes were ankle alignment, pelvic stability, ankle strength, ankle stability, and lower limb alignment. Screening measures consisted of medical history, teacher assessment, heel raise test, single leg plié, plantarflexion. Functional skills tests were heel raise test, single leg sauté, holding passé relevé on demi-pointe, balance, and pencil test. All agreed that teacher assessment is more reliable than a test battery. Overall, responses corresponded with statistically significant evaluators yet were not conclusive. Conclusion: Contradictory responses meant providing reliable outcomes to the objectives was challenging. Further research projects are needed to indicate any association between testing and teacher assessment for pointe readiness.

Background: Toe flexor strength, which involves the combined activation of plantar intrinsic and extrinsic foot muscles, is crucial for locomotion, balance, and performance. Strong toe flexors are particularly crucial for efficient propulsion during running and jumping. Therefore, strengthening the feet has gained increased attention in the general population, as well as among athletes and dancers. However, accurately assessing foot muscle strength remains challenging. This study investigated the within- and between-session reliability of toe flexor maximal voluntary isometric contraction (MVIC) using a custom-made dynamometer. Method: Twenty-five vocational ballet students (23 females and two males; age: 16.48 ± 1.2 years; mass: 53.06 ± 8.84 kg; height: 167.14 ± 6.4 cm; forefoot length: 6.55 ± 0.44 cm) participated in two data collection sessions 48 to 72 hours apart with three trials each session. The toes were positioned at a 25° dorsiflexion angle on the dynamometer. Results: Between-session reliability showed good to excellent intraclass correlation coefficient (ICC) values for absolute MVIC (aMVIC) of the right and left foot (ICC = 0.89-0.95; 95% CI: 0.75-0.96; coefficient of variation [CV]: 4.63-6.45). Toe flexor strength normalized to forefoot length and body weight (rTFS) was excellent for both feet (ICC = 0.91-0.95; 95% CI: 0.79-0.98; CV: 4.8-6.4). The minimal detectable change (MDC) ranged from 9.7% to 13.7% of individual scores. Within-session ICC values ranged from 0.92 to 0.95 (95% CI: 0.70-0.98), indicating excellent reliability across all measures. Discussion: Based on these findings, we recommend conducting at least one familiarization session and three trials per session to reduce the variability in toe flexor muscle strength measurements. The toe flexor dynamometer shows great potential for future research on toe flexor muscle strength in dancers, as well as monitoring back-to-stage rehabilitation progress and assessing pointe readiness.

Aim: To investigate quality of life (QoL) measures in a cohort of young female dancers. Methods: Cross-sectional survey study design was utilized to study dancers 8 to 17 years enrolled in two elite dance schools in the Boston area. The main outcome measure was the Pediatric Quality of Life (PedsQL 4.0) questionnaire, a validated QoL survey for children, with established normative values for comparison. Demographics and questions pertaining to training regimens and injury/illness history were also included. Sub-groups (8-11 years, 12-14 years, and 15-17 years) were created to analyze outcomes by age. Results: One hundred and forty emails were delivered, 72 were completed and included in the final data analysis (51.4%). The median scores for physical, psychosocial, emotional, social, and school PedsQL sub-scales were 87.5, 90.0, 80.0, 100.0, and 92.5, respectively. The median score of the total PedsQL scores was 88.8. No difference in QoL outcomes by age group was found (physical: P = .328; psychosocial: P = .918; emotional: P = .673; social: P = .573; school: P = 0.962; total: P = 0.766). 52.5% of the participants responded that they regularly perform in shows. Median hours/week of dance rehearsal was 10 hours (mean ± standard deviation: 10.3 ± 4.9; 95% CI: 9.0, 11.6; IQR: 7.0, 13.5; range: 2.0, 20.0) and 68.9% reported they practice and rehearse throughout the entire calendar year as opposed to solely during the school year; most dancers reported participating in dance 11 months (median value) per year (mean ± standard deviation: 10.7 ± 0.8; 95% CI: 10.5, 11.0; IQR: 10.0, 11.0; range: 9.0, 12.0). Conclusion: QoL measures for young female dancers were higher relative to existing data for the general population and lower compared to other sports participation. These results will support the social, emotional, and physical health of young dancers.