Journal of Dance Medicine & Science最新文献

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: 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: 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.

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: 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.

Background: Low back pain is a common disorder with high severity among dancers. Since Arabesque used in dance is more likely to cause lower back pain, it is important to prevent the onset of lower back pain during arabesque. Previous studies are investigating motion of the lumbar vertebrae during various tasks in targeting dancers. However, since the thoracic and lumbar vertebrae are connected, it is necessary to assess including motion of the thoracic spine. The purpose of this study was to clarify the relationship between the upper, middle, and lower thoracic vertebrae and the upper and lower lumbar vertebrae in dancers during arabesque. Methods: The participants were 13 university students with dance experience, and they performed double-standing and arabesque tasks. During the tasks, the positions of reflective markers attached to the spine (upper, middle, and lower thoracic vertebrae, and upper and lower lumbar vertebrae) were measured using a three-dimensional motion analysis system. The amount of change in the spinal angle of during standing and arabesque were calculated based on positions of spinal markers, and the relationship between the amount of change each spinal region (6 pairs) were analyzed by using Pearson's correlation test. Results: A significant negative correlation was observed between the amount of change in the angle of the middle thoracic vertebrae and the amount of change in the upper lumbar vertebrae (r = -.66, P = .013), which means that as the movement of the middle thoracic vertebrae increases, the movement of the upper lumbar vertebrae decreases. No significant correlation was observed between other spinal angles (P > .05). Conclusion: The results of this study suggest that increasing mobility in the middle thoracic vertebrae may be able to prevent hyperextension of the upper lumbar vertebrae, leading to the prevention of upper back pain in dancers.

Background: Ballet, epitomized by iconic seasonal performances such as "The Nutcracker," combines artistic expression with considerable physical demands. This study investigated the physiological and psychological responses of ballet dancers to the demands of intensive training and performance, with a specific focus on "The Nutcracker." Methods: Thirty- eight dancers volunteered for the study, including 6 youths (10.5 + 1.8 years, n = 6 female), 7 adolescents (15.4 + 1.1 years, n = 5 female), and 25 adults (21.1 + 2.1 years, n = 20 female). Employing an uncontrolled observational design, this pilot study tracked key biomarkers such as CK-MM for muscle damage and B-ALP for bone health, alongside psychological measures via PANAS-C/PANAS and DASS-21. Results: Significant findings included a post-performance reduction in cortisol and depression levels. Conclusion: These insights advocate for tailored strategies that address the multifaceted needs of dancers, acknowledging the intricate balance required to maintain peak performance and overall health within the demanding realm of professional ballet.

Introduction: The demipointe dance position puts the ankle at high risk of overuse injury and posteromedial ankle pain due to increased ankle valgus forces. Previous work has shown that creating lower limb external rotation intrinsic to demipointe with hip external rotation reduces foot pronation that causes ankle valgus stress. Therefore, the purpose of this work was to examine long axis rotation kinematics of the hip, knee, and ankle as well as the ankle joint contact forces in demipointe to better understand the biomechanical impact(s) of the specific cue to increase hip external rotation in this position. Methods: Three-dimensional motion capture and force plate data were collected from 23 contemporary or ballet pre-professional dancers (age: 19.94 ± 1.34 years) who each performed 3 dancer-selected (DS) demipointe positions and 3 demipointes with the cue to "externally rotate from the hips." Results: The cue to increase hip external rotation resulted in significantly increased hip external rotation angle [DS: 37.5; 9.42° (median; interquartile range), Cued: 39.9; 10.8°, P < .0001)] and significantly reduced ankle eversion angle (DS: 8.13; 11.4°, Cued: 7.77; 10.3°, P = .023). However, total turnout angle was also significantly decreased (DS: 75.8; 7.91°, Cued: 75.4; 7.73°, P < .0001), which is undesirable for proper esthetic performance of demipointe. Total ankle joint force remained unchanged, but ankle eversion force was significantly reduced (DS: 15.3; 4.18 %bodyweight (BW), Cued: 14.7; 4.99 %BW, P < .0001) with use of the cue. Discussion/Conclusion: Utilization of a cue to increase hip external rotation was successful in increasing hip contribution to turnout angle and reducing injurious ankle eversion force. Further coaching using this cue may allow dancers to produce these advantageous mechanics while maintaining turnout angle.

Aim: This study aimed to compare the effects of Ballroom Dancing (BD) versus Walking Training (WT) on the physical fitness performance in physically independent older women with adequate or inadequate levels of vitamins B12 and D.

Methods: Forty-three sedentary women aged 68.5 ± 6.5 years, were allocated to the BD (n = 23) or WT (n = 20) groups. They took part in a 12-week intervention, performed 3 times a week, for about 50 minutes with moderate effort intensity. Data were collected through Short Physical Performance Battery (SPPB), 6 minutes Walk Test (6MWT), Hand Grip Test (HGT), Isokinetic tests for lower limbs and blood tests to detect serum levels of vitamins B12 and D.

Results: The BD group performed better after the intervention in relation to the WT in the Sit and Stand Test (SST) (BD pre = 3.1 score vs post = 3.8 score; WT pre = 2.8 score vs post = 3.4 score; P = .02) and in the Peak Torque 180° extension (PKTOQ 180° extension) (BD pre = 56.7 Nm vs post = 61.2 Nm, WT pre = 56.7 Nm vs post = 56.1; P < .01).

Conclusion: A time effect was observed in all other variables, with the exception of HGT. Both interventions improved physical fitness performance, regardless of the adequacy of vitamins B12 and D, but the older women from BD obtained significant improvements in more variables than the WT.

Introduction: The Oslo Sports Trauma Research Centre Questionnaire on Health Problems (OSTRC-H) is a valid and reliable registration method for self-reported injuries and is regularly used among dancer populations. Monthly questionnaire administration is acceptable in athlete populations but has not been evaluated in dancers. The aim of this exploratory study was to assess the influence of weekly versus monthly administration of the OSTRC-H on estimated injury outcomes among elite adolescent ballet dancers.

Methods: Participants (n = 103) were prospectively followed for 6 months and completed the OSTRC-H online, evaluating perceived consequences of self-reported health problems during the previous week and the previous 4 weeks, respectively. Four definitions of dance-related injury were utilized: (1) all complaints, (2) substantial, (3) medical attention, and (4) time-loss injuries. Descriptive statistics estimated: (1) the number of injuries reported (count), (2) average injury prevalence [proportion, 95% confidence intervals (CI)], (3) average severity score (0-100), and (4) days of time loss (count) for each injury definition. The 4 outcome measures were then compared between weekly and monthly registration with paired sample t-tests (P < .05) and overlapping 95% CI.

Results: A significant difference between the number of all complaints injuries (weekly: 133; monthly: 94; P < .001) and substantial injuries (weekly: 64; monthly: 45; P = .012) was found. Regardless of injury definition, there were no significant differences between injury prevalence, severity scores, and days of time loss when reported weekly versus monthly.

Conclusion: Monthly administration of the OSTRC-H is an acceptable method to estimate injury prevalence, severity scores, and days of time loss amongst elite adolescent ballet dancers.