Journal of Dance Medicine & Science最新文献

Background: Développé is a leg gesturing skill commonly used in concert dance forms such as Ballet and Modern Dance. It requires mastery of subtle skills that make dance unique. Measuring unique dancer capacities such as développé can present special challenges for dance medicine and science researchers. Purpose and research design: One purpose of this study was to evaluate a field-deployable protocol for measuring the height of dancers' développé to the side. A second purpose was to use a concurrent multiple-baseline experimental design to determine whether each of six university dance majors nearing the end of their pre-professional training could improve their performance of développé through targeted training. Methods: During 4, weekly, 30-minute training sessions, dancers were taught an approach to performing développé advocated by an internationally recognized dance kinesiologist. The dancers also completed 3, self-guided training sessions per week in which they applied the approach while engaging in développé-related strengthening and stretching exercises. Each dancer's développé performance was measured twice weekly for 8-1/2 weeks (17 measurements). Results: All 6 dancers' développé height increased only when training was applied for each dancer suggesting that training, rather than other uncontrolled variables, was the likely cause of the improvements in performance. Conclusions: Two conclusions appear justified: (1) reliable and responsive measurements of développé height can be made efficiently in field settings, and (2) university dancers with considerable prior training can improve their performance of développé with targeted training.

Introduction: Ballroom dancing, particularly in its competitive form of dancesport, has been recognized for its beneficial effects on physical health and psychological well-being. In recent years, research attention has also shifted toward examining its associations with psychological constructs such as stress, anxiety, and coping. Study Design: The present cross-sectional comparative study aimed to compare sport dancers and non-dancers in the level of perceived stress and the coping strategies. Additionally, the study explored the relative contribution of specific coping strategies to perceived stress while controlling for sex, age, and dance status. Methods: The sample consisted of 119 participants aged 18 to 31, of whom 61 were competitive sport dancers. Research data collection was conducted using a form containing a demographic section focusing on dancesport, the Perceived Stress Scale (PSS-10) and the Brief COPE questionnaire. The results of the research do not indicate significant differences in levels of perceived stress; non-dancers, male and female sport dancers perceive stress at similar levels. Regarding coping, sport dancers also less frequently choose a problem-solving coping compared to non-dancers (P = .007). Defensive strategies were the most significant predictor of perceived stress of the sport dancers (P < .001). Conclusion: The research findings can be applied in sport and dance psychology, dance coach education, promoting the development of constructive coping in sport dancers via mental contrasting, advanced competition practice and as well as the overall training program in a dynamic dance environment.

Introduction: Sedentary lifestyles remain a persistent health issue in Japan. Ballroom dancing has recently gained attention as a potential means of maintaining physical activity, but there are very few reports on Japanese subjects. Exploratory research is therefore needed to investigate the effects of ballroom dancing on the physical and mental health of sedentary middle-aged Japanese adults. The aim of this study was to assess the impact of ballroom dancing on various health-related physical and psychological outcomes in middle-aged adults compared to a control group. Methods: A parallel-group study was carried out. Thirty healthy but inactive middle-aged adults with no previous dance experience were divided into 2 groups: an intervention group which participated in a recreational level ballroom dance program for 10 weeks (60 minutes, once per week) and a control group which had no dance lessons. Subjects completed questionnaires regarding subjective mood changes and daily physical activity. Objective measures of physical fitness, oxidative stress, antioxidant capacity, and autonomic nervous system function were also assessed before (T0) and after 10 weeks (T11) of dance practice. Results: In the subjective questionnaire, the Profile of Mood States 2 (POMS^®2) survey, one of the health-related indicators, T-scores of the Total Mood Disturbance (TMD) after the intervention showed a difference (P = .014) between the dance group and the control group. In post hoc tests, increases of autonomic activity and number of days of high-intensity physical activity correlated positively with a reduction in TMD in the dance group. Conclusion: Among inactive middle-aged adults, participation in weekly ballroom dance lessons for 10 weeks improved their psychological mood compared to a control group. The improvement was found to have the positive effects of activating autonomic nervous system activity and increasing high-intensity physical activity. The results suggest that ballroom dancing may be effective in improving exercise habits and physical and mental health.

Introduction: Ballet-based dance training emphasizes the equal development of both legs. However, dancers often perceive differences between their legs during balance or landing. There still needs to be more consensus on the functional difference between dominant (D) and non-dominant legs (ND). Therefore, this study investigated both legs' neuromuscular strategy in single-leg balance and landing based on leg dominance. Methods: Thirteen female dancers (age: 22.2 ± 2.8 years) with no history of ankle injuries in the past year participated in the study. Based on the questionnaire, the dominant leg was set, which legs were preferred to balance, generate strength, and land. Joint kinematics and ground reaction force (GRF) were analyzed using a three-dimensional motion analysis system and force plates during single-leg balance (SLB), passé balance (PB), sissone simple (SS), and sissone ouverte (SO). The tibialis anterior (TA), medial gastrocnemius (MG), peroneus longus (PL), and gluteus medius (GM) activation were measured by wireless surface electromyography (EMG). Displacement (cm) of the center of pressure and the dynamic postural stability index (DPSI), a balanced score post dynamic tasks, were calculated. Results: Bilateral leg balance ability was observed based on joint kinematics and DPSI during SLB, PB, SS, and SO. Higher TA activity was noted during PB in ND legs than in D legs (P = .038). PL activation was significantly increased in ND legs (69.3 ± 34.4%) than in D legs (45.6 ± 19.2%) before contact during SS and SO (P < .05). After landing with ND legs, dancers regulated postural stability with increasing TA activation (P < .05). Conclusions: Pre-activation of PL before landing with ND legs increases ankle stiffness, enhancing stability. Conversely, D legs achieve balance with lower activation levels. The findings highlight significant differences between legs in dancers, suggesting that leg dominance should be considered in future training and performance strategies.

Introduction: The use of neuromuscular interventions in sports induce meaningful motor performance in strength, sprint and power. The aim of this study was to investigate the effectiveness of the "11+ Dance" exercise program versus normal training (control) on possible adaptations in power, lower-body strength, and inter-limb asymmetry in adolescent ballet dancers. Study Design: Prospective randomized controlled trial. Methods: Dancers (n = 76) from a pre-professional ballet school volunteered for this study. Data from the two trials (pilot and main trials) were combined to protect the results from possible learning effect of the intervention. Participants were randomly assigned to either the 11+ Dance intervention (n = 38) or Control (n = 38). Participants completed at least 21 sessions over 7-9 weeks. The 11+ Dance intervention consisted of neuromuscular-based exercises, whereas the Control group carried out their normal routine. Baseline and post intervention outcome measures included countermovement jump (CMJ), reactive strength index (RSI), isometric mid-thigh pull (IMTP), and inter-limb asymmetry (ASYM). Results: Non-statistically significant improvements were noted for both 11+ Dance and control groups across outcome measures; CMJ F(1, 66) = 3.52, P = .065, ${\eta }_p^2$ = .051 (14% vs 8%), RSI F(1, 65) = 1.02, P = .316, ${\eta }_p^2$ = .015 (6% vs 13%), and IMTP F(1, 67) = 1.7, P = .197, ${\eta }_p^2$ = .025 (23% vs 18%). ASYM (F[1, 63] = .109, P = .743, ${\eta }_p^2$ = .002) (24% vs 15%). No statistically significant interaction for adherence was revealed for all the parameters. Conclusion: The 11+ Dance intervention elicited similar physiological adaptations as the Control group. Larger longitudinal studies are needed to investigate the efficacy of the 11+ Dance on injury incidence and severity as current evidence suggests prophylactic programs such as the 11+ Dance have an effect on injury prevention.

Introduction: There is currently little research relating specifically to the muscular strength and endurance requirements of the upper body such as lifts at varying heights, ground floor contact with the hands and inversions such as handstands. Enhanced understanding of muscular demands can inform training program design to build physical tolerance to meet the demand of the activity. The aim of this study was to ascertain the frequency of upper body muscular skills in contemporary and ballet dance performance. Methods: Analysis of 46 individual ballet performers (F = 23, M = 23) from 12 performances (duration 63.5 ± 44.5 minutes) and 44 individual contemporary performers (F = 21, M = 23) from 12 performances (duration 35.7 ± 4.3 minutes) was carried out. Frequency of upper body skills was recorded using Dartfish Easytag-Note and converted to mean frequency per minute of total performance and per performance by genre and by sex. Differences in frequency between genre were analyzed via Mann-Whitney U. Phase two analyzed differences between sex via Mann-Whitney U. Finally, analysis of differences between sex within dance genre was carried out via Wilcoxon signed rank test. Significance was accepted at P < .05. Results: A significant difference was apparent between ballet and contemporary dance for holding own weight (P < .05) with a greater total mean frequency within contemporary performances of 8.50 ± 9.03 compared to a total mean frequency of 1.51 ± 3.13 within ballet performances. Additionally, there was a significant difference for above shoulder assisted lift (P < .05) when comparing male dancers, with male contemporary dancers carrying out significantly more (9.82 ± 8.56) per performance than male ballet dancers (2.33 ± 4.66). A higher mean frequency of below shoulder lifts than above shoulder lifts was also noted, with the majority of above shoulder lifts remaining at eye level. Conclusion: Training programs must prepare dancers for upper body movements that consider differing biomechanical demands of a variety of lifts and inversions.

Introduction: Elite ballet is one of the most demanding physical activities for the skeleton, making dancers susceptible to bone stress injuries. This pilot study compared bone remodeling in professional female ballet dancers from the Royal Ballet Company with controls from Imperial College London. Methods: The study included dancers (n = 5, median age 29 ± 16 years) and controls (n = 6, median age 24 ± 8.5 years). The main outcome measure was bone turnover, assessed by measuring the ratio of resorption (NTX) and formation (P1NP) markers in urine and serum. Estrogen metabolism was evaluated through 2OH/16OH metabolite ratios. Both markers were measured using ELISA kits. Diet was tracked using 72-hour diaries, and weekly exercise hours were recorded through 2-week diaries and cross referenced with training logs. Results: Results showed significantly higher bone resorption to formation ratio (NTX/P1NP) in dancers versus controls (P < .050), and elevated estrogen metabolite ratios (2OH/16OH) (P < .010). These findings occurred despite similar dietary profiles between groups including fat (P = .874) carbohydrate (P = .501) and protein (P = .099). Dancers showed significantly higher weekly exercise hours (46.50 ± 38.75 vs 14.75 ± 11.75 hours/week, P < .001) and lower BMI (18.36 ± 1.35 vs 20.77 ± 3.66, P = .020). Conclusions: The pilot data suggest elite ballet dancers may exhibit an imbalance in bone remodeling with high resorption and low formation relative to controls. This imbalance in bone turnover markers could serve as a screening tool for identifying dancers at increased risk of bone stress injuries. The NTX/P1NP ratio could potentially offer a low-cost, non-invasive approach to identify at-risk dancers early and implement preventative measures. Further research and longitudinal trials are needed to test whether these markers can predict bone stress injury risk.

Introduction: Dance is physically demanding and often involves unilateral movements performed within a small base of support. Prior authors have reported that dancers use one leg preferentially over the other (ie, lower extremity asymmetry). Increased leg asymmetry-quantified using the Limb Symmetry Index (LSI), is associated with increased injury risk. Clinicians often use LSI to make return-to-performance decisions (eg, >85% performance on injured vs non-injured limb). However, limited research has examined leg symmetry in collegiate dancers. Purpose: To examine LSI in collegiate dancers using the modified star excursion balance test (mSEBT) and single-leg hop test (SLH). Methods: 120 healthy collegiate dancers (105 females, 15 males; 18.31 ± 0.80 years; 164.18 ± 7.12 cm; 61.18 ± 8.46 kg) performed the mSEBT (normalized to % leg-length: LL) in the anterior, posteromedial, and posterolateral directions and the SLH test (normalized to % body height: BH) across both legs using previously published guidelines. mSEBT scores were averaged for all three directions per leg. SLH scores were averaged per leg. LSI was calculated as (lower value/higher value) × 100 to obtain a percentage. Results: Mean mSEBT scores were 95.7 ± 14.2%LL (lower score) and 96.6 ± 14.3%LL (higher score). Dancers LSI for mSEBT was 99.1 ± 0.9%. Mean SLH scores were 82.8 ± 13.3%BH (lower score) and 86.4 ± 13.5%BH (higher score). Dancers LSI for SLH was 95.9 ± 3.5%. Conclusions: Dancers' LSI% was greater than 90% for mSEBT and SLH, concurrent with the normal values of LSI > 90% in healthy, physically active adults. Dancers displayed lower leg symmetry. Practitioners can thus use the contralateral leg as a reference for return-to-performance decisions following injury in dancers. LSI should be integrated into a comprehensive screening process to identify large (>85%) asymmetries and guide training programs post-injury to assist educators and practitioners' evidence-based return-to-performance decisions. Future researchers should examine LSI in other dance genres and across levels.Level of Evidence: 2C.

Introduction: As demanding as dancing en pointe is, no universal standard exists to determine when a ballet dancer is ready to advance to this next level. The goal of this study was to provide preliminarily tested and reliable guidelines for a screening tool that can be used to determine (1) if a dancer is ready for pointe, (2) reasons why a dancer may not be ready, and (3) areas for improvement to guide training and preparation. Methods: Participants: Seventeen dancers aged 9 to 17 years with a minimum 4 years of ballet and who were either possibly ready for pointe or had been in pointe class less than 3 months participated in this study. Study Design: Dancers were prospectively assessed by two physicians using the Pointe Assessment Screening Shah Edison (PASSÉ) tool for assessing pointe readiness. Interrater reliability and the relationship of individual tests to overall pointe readiness were evaluated using descriptive statistics, kappa, diagnostic metrics, and logistic regression. Setting: Private practice office; ballet studios. Results: There was 94% agreement among raters in determining overall pointe readiness, and individual tests all had significant interrater agreement ranging from 62% to 97% (P ≤ .04). Ankle plantarflexion >90° (100%), stability in grand plié (100%), and holding relevé (96%) had the highest sensitivity for overall readiness, indicating their necessity to advance to pointe. The tests with greatest specificity for identifying lack of readiness were relevé passé (72%), sauté (72%), and airplane (69%). Conclusions: This study provides preliminary testing of a reliable screening tool, the PASSÉ screen, which can be utilized to determine pointe readiness with excellent interrater agreement for the overall pass/fail and significant agreement for tests that contribute to readiness. At minimum, dancers must be able to pass the grand plié, ankle plantar flexion, and relevé tests. Also passing the sauté, relevé passé, and airplane tests indicates high likelihood of readiness.