Journal of Dance Medicine & Science最新文献

Background: Research on improving dancer fitness to enhance performance capacity and prevent injury continues to grow. Fitness research for the adolescent dance team population, however, presents an evidence void.

Purpose: Utilizing studio-based assessments, this descriptive quantitative study reveals an initial set of fitness normative values for the female adolescent competitive dance team dancer population.

Methods: 115 female dance team dancers ages 12 to 17 participated in a 90-minute field test assessment battery for cardiorespiratory fitness, muscle endurance of the upper body, lower body, and core, and lower extremity power. Descriptive statistics (mean, standard deviation, and interquartile range) created an initial set of quantitative fitness normative values for this population.

Results: Dancers' results revealed 29.5mL/O2×min ± 5.7 estimated VO2max, 35 ± 16 push ups, 62 ± 14 half sit ups, 51 ± 13 squats in 1 minute, 190 ± 23 cm broad jump, 445 ± 65 cm right lower extremity triple hop, and 450 ± 69 cm/left lower extremity triple hop.

Conclusion: Discussion includes comparison of findings relative to previously established adolescent fitness and dancer normative data. Discussion also suggests implications, study limitations, and future research directions.

Introduction: Breaking, often mislabeled as breakdancing in the media, is a dance style originating from the Bronx of New York in the early 1970s. A unique condition in this population is a form of alopecia known as "headspin hole," or "breakdancer overuse syndrome" of the scalp. This form of hair loss may show a variety of patterns based on the activities of the dancer. The purpose of this study was to investigate the relationship between alopecia and breaking, the level of concern dancers have regarding hair loss, barriers to medical treatment, and how it affects their dancing.

Methods: This was a cross-sectional study using an online survey. The survey addressed participants' demographics, hair, dancing styles, training, and health history. Questions about the effects of hair loss on the participants were also asked.

Results: This study found that there was a significant difference in hair loss among breakers compared to non-breakers. This was not seen after controlling for age and sex. However, the concern for hair loss was significant even after controlling for these variables. Similarly, hair loss was significantly associated with the frequency of headspins. Despite these concerns, breakers were less likely to seek medical attention.

Conclusions: This study showed that there are significant disparities in hair loss between breaking and other dance styles. Hair loss due to breaking has been shown to have significant effects on an individual's concerns, which may be compounded by the fact that this population is less likely to seek out medical care and have significantly greater substance use compared to the other dancers surveyed. Further research is necessary to investigate interventions to prevent and treat hair loss in this population and the means to decrease the gap in health care in the dance population.

Introduction: Urinary incontinence (UI) is a common issue in female athletes and is known to negatively impact quality of life and sport performance. However, the prevalence of UI in dancers has not been widely investigated. The purpose of this study was to assess the prevalence of UI as well as other symptoms of pelvic floor dysfunction in female professional dancers.

Methods: An anonymous online survey that included the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) was developed and distributed via e-mail and social media. Two hundred and eight female professional dancers between the ages of 18 and 41 years (mean: 25.4 ± 5.2 years) who had a typical dance training and performance schedule of 25 hours or more per week completed the survey.

Results: A total of 34.6% of participants reported experiencing UI, with 31.9% of the dancers who reported UI reporting symptoms consistent with urge UI, 52.8% reporting UI with coughing or sneezing, and 54.2% reporting UI with physical activity or exercise. For those reporting UI, the mean ICIQ-UI SF score was 5.4 ± 2.5 points and the mean score for impact on everyday life was 2.9 ± 1.9. A report of pain with sexual activity and intercourse was significantly associated with presence of UI (p = 0.024), but the effect size was not notable (phi = 0.159).

Conclusion: The prevalence of UI in female professional dancers is similar to that found in other high-level female athletes. Based on the notable prevalence of UI, health care professionals working with professional dancers should consider regularly screening for UI and other symptoms of pelvic floor dysfunction.

Dancers need adequate cardiorespiratory fitness (CRF) levels in order to cope with the demands of dance classes and choreographies. Screening and monitoring of CRF is advised. The aim of this systematic review was to provide an overview of tests used to assess CRF in dancers and to examine the measurement properties of these tests. A literature search was performed in three online databases (PubMed, EMBASE, and SPORTDiscus) up until August 16, 2021. Study inclusion criteria were: 1. a CRF test was used; 2. participants were ballet, contemporary or modern, or jazz dancers; and 3. English full-text peer-reviewed article. General study information, participant information, CRF test used, and study outcome were extracted. If available, measurement property data were extracted (i.e., test reliability, validity, responsiveness, and interpretability). Of the 48 articles included in the review, most used a maximal treadmill test (n = 22) or the multistage Dance Specific Aerobic Fitness test (DAFT; n = 11). Out of the 48 included studies, only six examined the measurement properties of CRF tests: Aerobic Power Index (API), Ballet-specific Aerobic Fitness Test (B-DAFT), DAFT, High-Intensity Dance Performance Fitness Test (HIDT), Seifert Assessment of Functional Capactiy for Dancers (SAFD), and the 3-minute step test. Good test-retest reliability was found for the B-DAFT, DAFT, HIDT, and SAFD. Criterion validity was determined for the VO_2peak of the API, the 3-MST, HIDT, and SAFD. For HR_peak, criterion validity was studied for the 3-MST, HIDT, and SAFD. While different CRF tests are being used in descriptive and experimental research within dance populations, the body of research supporting the measurement properties of such tests is very small. As many studies have methodological flaws (e.g., small participant numbers or no statistical analysis for validity or reliability), additional good quality research is required to re-examine and complement current measurement property results of the API, B-DAFT, DAFT, HIDT, SAFD, and 3-MST.

Introduction: Ankle sprains are the most common acute injury among dancers and may result in the development of chronic ankle instability (CAI). Chronic ankle instability is characterized by recurrent ankle sprains, incidents of the ankle "giving way," and sensations of instability and has been reported to negatively impact functioning and psychosocial status. The large number of ankle sprains in addition to contextual factors relating to professional dancing, suggests that CAI may be a significant problem in professional ballet dancers. This study aimed to determine the prevalence of CAI and describe the ankle injury history and level of self-reported function in South African ballet dancers.

Methods: This descriptive, cross-sectional study included all professional ballet dancers employed by three professional South African ballet companies (n = 65). The Identification of Functional Ankle Instability Questionnaire (IdFAI), Foot and Ankle Ability Measure (FAAM), Dance Functional Outcome Survey (DFOS), and a researcher-developed injury history questionnaire were completed by consenting participants. Descriptive statistics were calculated.

Results: A CAI prevalence of 73.3% CI [55.6%, 85.8%] was calculated among 30 participants. Twenty-five (83.3%) participants reported sustaining at least one significant ankle sprain with 88% (n = 22) indicating dance related activities as the cause. Dancers with CAI demonstrated a tendency to have less control over their ankles giving way and tended to take longer to recover from their ankles giving way than those dancers not affected. Eight participants (36.4%) with CAI were identified as having a significant level of disability on the FAAM activities of daily living (ADL) subscale and six participants (27.3%) on the sport subscale. Participants with CAI had a median total score of 83.5; IQR [80 - 90] on the DFOS.

Conclusion: The self-reported function of South African professional ballet dancers is not severely affected, however, the high prevalence of CAI and reported symptoms is concerning. Education on CAI symptoms, prevention, and evidence-based management is recommended.

Hip hop is a popular dance genre practiced worldwide that has gained popularity since the 1970s. Despite this, studies related to the area and its physiological demands are still scarce. The purpose of this study was to report the cardiorespiratory profile of a group of male and female hip hop dancers to determine the zones of intensity of a predefined hip hop party dance sequence. Eight Brazilian professional hip hop dancers, four women and four men, mean age 22 ± 2.3 years, participated in the study. Using a portable gas analyser (Cosmed K5) their cardiorespiratory variables were measured at two different times: first, during a maximal treadmill test and later during a predefined hip hop party dance sequence. Descriptive statistics (mean and standard deviation) were used for calculating the dependent variables: oxygen consumption (VO₂), heart rate (HR), and the intensity zones for the predefined hip hop sequence. Data normality was verified using the Shapiro-Wilk test. The Mann-Whitney U-test was performed to check any sex-related difference (p < 0.01). No statistical difference between male and female dancers was found in the cardiorespiratory profile and responses to the predefined hip hop party dance sequence. On the treadmill, the participants' VO_2peak was 57.3 ± 12.7 ml·kg^-1·min^-1, and HR_max was 190.0 ± 9.1 b·min^-1. The predefined hip hop party dance sequence was mainly (61%) performed in the moderate aerobic zone. However, when the dancers jumped, the intensity of the sequence increased. This information could be used to develop a specific supplementary training protocols for hip hop dancers to improve their physiological fitness parameters and reduce the incidence of injury.

Introduction: Few studies have published data concerning the longitudinal rehearsal and performance demands experienced by professional ballet dancers. We aimed to describe the rehearsal and performance volumes undertaken across five professional ballet seasons and identify factors associated with inter-dancer and inter-production variation in dance hours.

Methods: Scheduling data were collected from 123 dancers over five seasons at The Royal Ballet. Linear mixed effects models were used to evaluate differences in: 1. weekly dance hours and seasonal performance counts across sexes, company ranks, and months; and 2. factors associated with the variation in rehearsal hours required to stage different productions.

Results: On average across the five seasons, a peak in performance volume was observed in December, whereas rehearsal hours peaked in October and November and between January and April. Differences in weekly dance hours were observed between company ranks (p < 0.001, range in means: 19.1 to 27.5 hours per week). Seasonal performance counts varied across company ranks (p < 0.001), ranging from 28 (95% CI: 22, 35) in principals to 113 (95% CI: 108, 118) in the rank of artist. Rehearsal durations were considerably greater in preparation for newly created ballets compared with existing ballets (77.8 vs. 37.5 hours). Rehearsal durations were also greater in preparation for longer ballets, with each additional minute of running time associated with a 0.43 hour increase in rehearsal duration (p < 0.001). Full-length ballets, however, were consistently the most time-efficient to stage due to their long performance runs compared with shorter ballets (16.2 vs. 7.4 performances).

Conclusions: Training principles such as progressive overload and periodization should be implemented in professional ballet companies to manage the high and variable rehearsal and performance loads.

Introduction: This study investigated how toe flexor muscles are related to postural stability in 11 ballet dancers and 12 non-dancers.
Methods: Toe flexor strength (TFS), cross-sectional areas (CSA) of the abductor hallucis, flexor hallucis brevis, flexor digitorum brevis, flexor hallucis longus (FHL), and flexor digitorum longus, and center of pressure (COP) displacement during single-leg demi-pointe were measured. Correlations between toe flexor strength and COP displacement and between CSA and COP displacement within each group were calculated using Pearson's correlation coefficient or Spearman's correlation coefficient.
Results: The dancers showed smaller COP displacement than the non-dancers (p < 0.05). Toe flexor strength in dancers was moderately negatively correlated with COP displacement in the anterior-pos- terior direction (r = -0.54, p < 0.01) and total COP displacement (r = -0.57, p < 0.01). Only the CSA of the FHL in dancers exhibited a significant negative correlation with COP displacement in the anterior-posterior direction (r = -0.42, p < 0.05) and total COP displacement (r = -0.52, p < 0.01).
Conclusion: The present study found a relationship between the toe flexor strength and COP displacement and CSA of toe flexor muscles and COP displacement during one-legged demi-pointe standing. These results suggest that the development of the toe flexor muscles may be involved in the balance control of dancers.

This study aimed to investigate the perceptions of training load practices of dance artistic and health professionals. Artistic staff and health professionals with experience in dance were invited to participate in a cross-sectional survey study relating to training load practices in pre-professional and professional, ballet and contemporary dance. The survey was developed from previous investigations in soccer and consisted of multiple-choice, Likert scale, and free-text responses. Responses to closed questions were reported by percentage and 95% confidence intervals (95% CI). Thematic analysis was performed by two independent assessors of free-text responses. There were six artistic staff and 18 health professional participants. Artistic staff were perceived to be "mostly/completely responsible" for planning training (artistic staff: 100%, 95% CI: 61%, 100%; health professionals: 94%, 95% CI: 76%, 100%), with health professionals "mostly/completely responsible" at times of injury (artistic staff: 83%, 95% CI: 41%, 99%; health professionals: 95% CI: 61%, 96%). Both groups reported using individual modification to manage training loads and recognized the benefits of rest. Artistic staff recognized the need to modify training when injured, in line with experience levels, workload, age, and general health. Both groups "agree/strongly agree" that monitoring would be or is useful (artistic staff: 83%, 95% CI: 41%, 99%; health professionals: 95% CI: 61%, 96%). This investigation provides insight into the perceptions of artistic staff and health professionals with experience in dance toward training practices. Artistic staff and health professionals need to work together and adapt monitoring practices to their context to support artistic staff in planning training. The findings guide the implementation of these interventions by understanding potential barriers to their effectiveness that may potentially reduce injury.

Objectives: Performance anxiety (PA) is debilitating and impacts the sufferer's ability to perform. Forgetfulness, concentration loss, and physical symptoms develop, leading to some giving up performing.
Methods: An online questionnaire was used to gather data, including demographic questions and the Kenny Music Performance Anxiety Inventory (K-MPAI). The questionnaire was distributed via social media and the British Association for Performing Arts Medicine (BAPAM) database. Data was collected over a 2-month period and was analyzed using simple proportions with a score of ≥ 104 on the K-MPAI indicating the presence of PA and ≥ 130 indicating notable levels of PA.
Results: Thirty-three participants completed the questionnaire (57.6% female). When looking at the ages of participants (18 to 80), the most common age range was 31 to 35 (33%). Two-thirds of participants were deemed to suffer from PA after completing the K-MPAI. A large proportion of participants with PA (63.6%) scored above the threshold score of 130 indicating "significant performance anxiety." Females or currently unemployed performers showed higher levels of PA than other subgroups. However, a chi-squared test showed no significance between sexes (p = 0.32) or employment status (p = 0.31) and the incidence of PA.
Conclusion: The research showed that PA is a significant issue in musical theater, as it is with other musicians who have been studied extensively. We conclude that more research is needed to look at appropriate treatments specifically for musical theater performers.