Journal of Dance Medicine & Science最新文献

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.

Introduction: Measurement of performance quality in dance is important but challenging and few dance performance quality measures exist. This study aims to (1) identify and (2) assess the quality of dance performance outcome measures for ballet, modern and contemporary dance. Methods: A 2-step systematic review with two separate literature searches was conducted. Step 1 involved a systematic review to identify all ballet, modern and contemporary dance performance quality outcome measures. Step 2 involved a systematic review to identify studies that reported measurement properties (eg, validity, reliability) of the tools identified in Step 1. A comprehensive electronic search of MEDLINE, SPORTSDiscus, CINHAL, Embase and IADMS Bibliography was conducted from inception to November 2020 (Part 1) and February 2021 (Part 2). To evaluate the quality of each dance performance outcome measure, three steps were conducted (1) assessment of methodological quality using the COSMIN checklists, (2) evaluation of results against criteria of good measurement properties and (3) summary of the evidence and an overall rating of evidence using a modified Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results: Fifteen dance performance quality outcome measures were identified (Step 1). Seventeen studies reported measurement property data for 14 of 15 identified outcome measures (Step 2). The majority of the 34 measurement property outcomes were rated as doubtful (COSMIN checklists), and demonstrated sufficient measurement properties. Only one outcome measure, the Radell Evaluation Scale for Dance Technique (RESDT), was assessed as having low and moderate quality evidence for validity and reliability respectively. The remaining 13 tools were rated as having very low-quality evidence (GRADE criteria). Conclusions: Due to low quality, the 15 dance performance quality tools cannot be confidently recommended for use at this time. Dance teachers, clinician and researchers should consider feasibility issues and use the tools with caution until adequate high-quality evidence is available.

Introduction: Ballet demands diverse physical prowess, requiring dancers to execute movements symmetrically, irrespective of their dominant leg. Ballet often includes jumps, including the basic open-leg leap-the grand jeté-which requires uniform performance regardless of the leg on which the leap is initiated. However, no studies have simultaneously evaluated the effects of dominant leg or movement variation on jump height, leg split angle, jump time, and floor reaction forces during take-off and landing, which are related to the feeling of floating in the grand jeté. This study aimed to determine whether the high-level, stable, and beautiful performance required of professional ballet dancers in the grand jeté is affected by the dominant leg. Methods: Twelve female ballet dancers, all right leg dominant, performed the grand jeté 3 times on each side, distinguishing between dominant (right leg landing) and non-dominant (left leg landing) grand jetés. Utilising 3D movement analysis, we measured jump height, jump time, maximum leg split angle, and maximum vertical ground reaction force (VGRF) during take-off and landing. Mean values and coefficients of variation were calculated for each analysed parameter. Paired sample t-tests were conducted to assess differences between left and right grand jetés, with a significance level set at P < .05. Results: Statistically significant differences were observed in jump height (P = .028) and jump time (P = .001) when comparing the average of three trials for each side. However, no significant differences were found in maximum leg split angle (P = 0.643), maximum VGRF at take-off (P = .200), and maximum VGRF at landing (P = .109). In addition, no significant differences in coefficients of variation were identified for all items. Conclusion: Ballet dancers showed consistent performance on dominant and non-dominant legs but higher and longer jumps for grand jetés landing on the dominant leg, which may have affected overall performance.

Purpose: This study examined risk and protective factors in dancers with/without posttraumatic stress disorder (PTSD) and with/without trauma exposure.

Literature review: Exposure to traumatic events and developing PTSD can compromise daily functioning and performance ability. Despite exposure many dancers adapt, whereas others suffer psychopathology such as depression, anxiety, PTSD, and difficulties regulating emotions.

Methods: Two hundred ninety two pre-professional/professional dancers provided informed consent (IRB approved) and completed 8 self-report measures. A subsample (66%) exposed to a significant traumatic event was evaluated for PTSD. Multivariate analyses of covariance (MANCOVA) were conducted to compare dancers with/without PTSD and with/without trauma exposure. A logistic regression analysis determined predictors of PTSD.

Results: The MANCOVAs indicated that dancers exposed to trauma (66%) and who had PTSD (32%) had significantly more difficulty regulating emotions, engaged more emotion-oriented coping under stress, and had increased depression, trait anxiety, and cumulative trauma. In these group comparison analyses there were non-significant differences regarding flow experiences and task- and avoidance-oriented coping strategies. In the logistic regression analysis childhood physical and sexual abuse, childhood emotional neglect, mental illness within the family, and difficulty disclosing abuse experiences were predictors of PTSD. In the total sample 21% had PTSD.

Discussion and conclusions: This study identified types of abuse/trauma, emotion regulation/coping, and psychopathology associated with PTSD in dancers exposed to trauma (66%) and with PTSD (32%). In the total sample 21% had PTSD. Regardless of exposure to trauma or PTSD, the non-significant findings indicated similarities for dancers for global and autotelic flow experiences and task- and avoidance-oriented coping strategies. These positive factors may mitigate trauma-related symptoms. It is recommended that dancers, educators, and clinicians understand the effects of trauma exposure and promote the development of effective coping strategies, emotion regulation, and flow states which may diminish the negative effects of PTSD.

Introduction: In classic ballet, choreography often involves tiptoe standing. Tiptoe standing requires a high and stable foot arch structure, which is achieved by contraction of the plantar intrinsic foot muscles (PIFMs). Long-term repetitive loading with a specific movement can induce hypertrophic adaptation of the associated muscles. For dancers, however, limited information on the size of individual PIFMs is available from previous studies. The purpose of this study was to determine the differences in the sizes of 10 individual PIFMs between dancers and non-dancers.

Methods: Muscle volumes (MVs) of 10 individual PIFMs were measured using magnetic resonance imaging in 15 female dancers and 15 female non-dancers. Muscles analyzed included abductor hallucis, flexor digitorum brevis, abductor digiti minimi, quadratus plantae, lumbricals, flexor hallucis brevis, adductor hallucis oblique head, adductor hallucis transverse head, flexor digiti minimi, plantar/dorsal interossei. In addition to absolute MVs, relative MVs normalized to body mass (rMV_BM) and the percentage of individual MVs relative to the sum of 10 individual PIFM MVs (%MV_WHOLE) were calculated.

Results: The absolute MVs of 6 individual PIFMs, including the flexor digitorum brevis and lumbricals, were +16% to 59% larger in dancers than in non-dancers (P ≤ .048). The rMV_BM of all individual PIFMs were +35% to 95% larger in dancers than in non-dancers (P ≤ .019). The %MV_WHOLE of the flexor digitorum brevis and lumbricals were +10% to 36% higher (P ≤ .014) and those of the abductor digiti minimi and adductor hallucis oblique head were +8% to 11% lower (P ≤ .037) in dancers than in non-dancers.

Conclusions: For all 3 MV measures, only the flexor digitorum brevis and lumbricals, which are functionally specialized for flexion of the second to fifth metatarsophalangeal joints, were consistently larger in dancers than in non-dancers. This may be due to long-term repetitive loading on these PIFMs during ballet training involving tiptoe standing.

Introduction: While several studies have analyzed the characteristics and burden of injuries and physical complaints in (pre-)professional dancers, mental health problems, other than eating disorders, have rarely been studied in professional ballet dancers. The aims were to (a) investigate the prevalence of self-reported mental health problems, and (b) analyze their potential associations with sleep disturbance, coping skills and social support in professional ballet dancers. Methods: During a pre-season health screening, professional ballet dancers of three companies were asked to answer questions on personal characteristics, current need and attempt to lose weight, chronic/recurrent mental health problems, and need of support from a psychotherapist as well as established questionnaires on depression (PHQ-9), generalized anxiety (GAD-7), eating disorders (EDE-QS), sleep disturbance (ASSQ), athletic coping skills (ACSI-28) and perceived social support (F-SozU-K6). Results: All 96 dancers (average age 27.3 years, 51.0% male) who participated in the screening answered the questionnaire. In the PHQ-9, 19 (19.8%) dancers reported mild, and 4 (4.2%) moderate to severe symptoms. In the GAD-7, 19 (19.8%) dancers reported mild, 11 (11.5%) moderate and three (3.1%) severe symptoms. Ten (10.4%) dancers were screened positive for an eating disorder in the EDE-QS. Almost two thirds of the dancers reported sleep problems of mild (n = 39; 40.6%), moderate (n = 19; 19.8%) or severe extent (n = 3; 3.1%) in the ASSQ. One in five dancers (n = 19; 19.8%) wanted or needed support from a psychotherapist at the time of the screening. The mean score of ASSQ correlated significantly with PHQ-9 (r = .34; P = .001) and GAD-7 (r = .27; P = .008). Correlations of mental health problems with athletic coping skills and social support were generally low. Conclusion: The prevalence of mental health problems, especially anxiety and eating disorders, was high in professional ballet dancers. Routine screening of mental health and sleep problems as well as interventions to improve mental health and sleep quality are strongly recommended. Level of Evidence: 2b cross-sectional study.

Background: Mindfulness and acceptance-based approaches have been trialled in professional sport. The present pilot study was a randomized controlled trial with professional ballet dancers investigating the effectiveness of the Mindfulness-Acceptance-Commitment (MAC) approach, developed for athletes, compared to an education program which included topics relevant to ballet and performance. Methods: Participants included 16 professional ballet dancers (2 men and 14 women) who were randomly assigned into either the MAC or education group for 1 session per week, for 6 weeks. Participants were assessed pre-and post-intervention using the Mindfulness Inventory for Sport (MIS) and the Acceptance Action Questionnaire (AAQ-II). Within 2 weeks of the final mindfulness session, all participants completed a semi-structured interview. Results: No differences were found when comparing the questionnaire responses between pre- and post- intervention, nor between the MAC group and the control group at post intervention for all subscales. Although dancers reported in the interviews that the sessions were valuable, they advised their ability to dedicate time to mindfulness ongoing would be challenging. Conclusions: Mindfulness interventions, as explored in this study, show promise to promote the well-being of professional ballet dancers. For consistent and ongoing mindfulness practice, future designs should seek to embed mindfulness practice into dancer and company schedules.