Journal of Dance Medicine & Science最新文献

Objectives: To explore reconstructed identities of dancers who experienced an injury, using a model of identity reconstruction post-injury. Methods: An online questionnaire study with 145 dancers who had experienced a significant dance-related injury. Measures included a questionnaire measuring dancers' reconstructed identities, injury perceptions and injury centrality to self-concept. Statistical analyses included factor analysis, regression analyses and discriminant analysis. Results: Four latent variables discovered "supernormal self," "former self," "middle self," and "resentful self" reconstructed identities. Injury centrality to the self and specific injury perceptions were correlated with reconstructed identity scales in the predicted directions. Conclusions: The findings validated the existence of 4 distinct reconstructed identities associated with time distance from the injury. Classifying injured dancers according to these identities can help dance educators, practitioners and counselors detect dancers needing help and tailor counseling methods to modify the relevant injury perceptions.

Objective: To investigate the effects of a dance intervention on selected functional parameters during the 180° turning phase of the Timed Up & Go (TUG) test in people with Parkinson's Disease (PwPD). Methods: Fifteen adults clinically diagnosed with idiopathic PD were allocated into dance intervention (DIG; n = 7 ; age 73 ± 2 years) and control (CG; n = 8; age 64 ± 5 years) groups. The dance intervention lasted for 3 months (1 hour, twice a week). At baseline, all participants completed the Unified PD Rating Scale-part III, the International Physical Activity Questionnaire-short form, and the Hoehn & Yahr scale. Pre- and post-intervention, the primary outcomes were measured (number of steps and time to complete the 180° turning phase of the TUG test) at 2 speeds (comfortable walking and as quickly and safely speed) while using the Xsens^® 3D motion suit. The secondary outcome (girdle dissociation) was assessed by calculating the difference between pelvis and affected shoulder orientation in the transverse plane (dissociation angles) at each data point during the TUG test's 180° turning phase. Results: At participant's comfortable walking speed, the functionality during the 180° turning remained unaffected following the dance intervention. However, at participant's fast speed, the dance intervention group significantly reduced the number of steps with a large effect size, and the total time taken to complete the 180° turning with a medium effect size. Post-intervention, most participants in the dance intervention group reduced the affected shoulder and pelvic girdle dissociation and turned more "en bloc." Conclusion: Dance can improve selected functional parameters during the 180° turning at fast speed in PwPD. The current results should be considered in rehabilitation programs.

Introduction: Ballet dancers have a special morphology, such as a large muscle thickness that affects passive torque. Ballet dancers also possess specialized mechanical, and neural properties of muscles and tendons. These characteristics may produce different static stretching effects than non-dancers. Therefore, this study aimed to determine the differences in the effects of static stretching on joint range of motion, passive torque, and muscle strength between ballet dancers and non-dancers. Methods: This study included 13 ballet dancers and 13 college students. The muscle and tendon thicknesses were assessed using ultrasonography. In the right lower extremity, torque-angle data and muscle-tendon junction displacement measurements were obtained during isokinetic passive dorsiflexion before and after a 5-minute static stretch against the right plantar flexors. The relative stretching intensity was calculated by dividing the stretching angle by the maximal dorsiflexion angle pre-stretch. Additionally, the isometric maximal voluntary plantar flexion torque on the left ankle was measured before and after 5 minutes of static stretching against the left plantar flexors. Results: Ballet dancers had significantly greater muscle thickness than non-dancers (22.4 ± 2.2 vs 18.1 ± 1.7 mm), whereas no significant difference was observed in the Achilles tendon thickness. No significant difference was observed in the stretching angle; however, the relative stretching intensity was higher in the control group (65.9 ± 19.8 vs 127.5 ± 63.8%). Static stretching increased the maximal dorsiflexion angle (dancer: 30.4° ± 9.6° to 33.9° ± 9.5°, non-dancer: 18.4° ± 8.6° to 20.5° ± 9.5°) and maximal passive torque in both groups, whereas the maximal isometric plantar flexion torque and submaximal passive torque decreased. However, no significant differences were observed in the changes between the groups. Conclusion: These results indicate that despite having a lower relative stretching intensity, ballet dancers experienced similar changes as non-dancers after 5 minutes of static stretching.

Introduction: Promoting physical wellness for preschool-aged children with developmental disorders (DD) is a known challenge. Interventions are more likely to succeed when physical activity opportunities are available to children within the context of their typical environments. We evaluated the feasibility and preliminary effect of 1 potential solution: structured creative dance classes delivered within a preschool environment.

Methods: Using a non-randomized feasibility study design, we offered physical activity in the form of creative dance classes for children with and without DD within an inclusive preschool. Classes lasted 30 minutes and were held once a week or 7 weeks. We measured attendance (primary), observed active participation (% of class duration), and balance (Pediatric Balance Scale). Non-parametric descriptive statistics are expressed as median (interquartile range). Balance was evaluated regarding (a) difference between groups at baseline (Mann-Whitney statistic) and (b) intervention effect for children with DD (1-tailed, paired t-test).

Results: Twelve preschoolers (age range = 3-5 years) participated: 4 with DD and 8 with neurotypical development. Attendance was 93% (79%-100%) for children with and 100% for children without DD. Per class, rate of active participation in dance activity was 33% (28%-45%) for children with and 80% (71%-82%) for children without DD. Starting balance scores were lower (P = .014) for children with DD (42 (39-45)) compared to those without (51 (50-52)). Post-intervention, balance scores improved for the children with DD to 50 (50-51) (df = 3, p = .014, t-statistic = 2.35); each child with DD surpassed minimal detectable change for balance.

Conclusion: Creative dance classes, delivered within an inclusive preschool environment, are feasible for some preschool-aged children with DD to participate in and efficacious as a physical training challenge at low activity doses. More study is warranted of this potential solution to meet the need for physical wellness promotion among young children with DD.

Background: Achilles tendinopathy can be a devastating condition in ballet dancers. Initial medical evaluation is frequently conducted by generalist physicians, who may lack the perspective of dance and sports medicine focused training and often prescribe complete rest for chronic overuse injuries. In order to provide targeted information about Achilles tendinopathy and the unique needs of elite athletes, such as ballet dancers, we designed an educational intervention that covers relevant anatomy, physiology, biomechanics, clinical presentation and evaluation, and recommendations for initial treatment and sub-specialty referral. The objectives of this study were to determine baseline understanding of Achilles tendinopathy by generalist physicians and to evaluate the efficacy of an educational intervention on their knowledge.

Methods: This was a prospective pre- post-test study, to measure improvement in knowledge about Achilles tendinopathy. Emergency Medicine and Primary Care physicians participated in an educational intervention with didactic and hands-on components. Data were analyzed using a two-tailed t-test.

Results: Twenty generalist physicians participated. There was significant improvement in their knowledge of Achilles tendinopathy for all our educational objectives (Pre-test: 59% correct answers; post-test: 79% correct answers; P < .0001; 95% CI: 6.32-10.78.).

Conclusions: A brief educational intervention leads to increased knowledge of Achilles tendinopathy in generalist physicians. By increasing awareness of Achilles tendinopathy through a standard educational model, we propose that our curriculum can be portable and accessible to all health care providers who encounter dancers and other athletes with Achilles tendinopathy and may serve as a model for expanded education to generalists about other conditions commonly encountered in ballet dancers.

Introduction: The menstrual cycle is an important indicator of health in female athletes. Female elite adolescent dancers are expected to control their weight while also training intensely, which can lead to menstrual disorders. This study aimed to investigate the relationship between body composition and menstrual status in female elite adolescent dancers. Methods: In total, 131 female elite adolescent dancers (age: 15.9 ± 1.5 years) were enrolled in this study. We measured the height, weight, and body fat percentage (BFP) for each participant and calculated their body mass index (BMI). We gathered information on individual menstruation patterns and the participants' menstrual cycles over the previous year using recall methods. We then compared the differences between dancers with menstrual cycle disorders and those without. Primary amenorrhea was defined as menarche occurring after the age of 15, while secondary amenorrhe was defined as experiencing fewer than 5 or no menstrual periods for at least 3 of the previous 12 months. We conducted a reliability test using the same questionnaire 2 weeks later. Statistical significance was defined as P < .05, and we calculated the effect sizes (d) and 95% confidence intervals (95% CI). Results: The average BMI and BFP were 22.6 ± 3.0% and 19.4 ± 2.2 kg/m², respectively. Low BFP and low BMI were observed in 51 (38.6%) and 47 (35.6%) participants, respectively. Primary amenorrhea in 3 participants (2.3%) and 29 (22.1%) reported experiencing secondary amenorrhea; they had lower BFP than the dancers who did not experience amenorrhea (P = .041, 95% CI, -2.51 to -0.05). Conclusion: Female elite adolescent dancers in China may have lower BFP and menstrual problems. Given that lower BFP may contribute to the occurrence of menstruation disorders, it is essential to pay an attention to both BFP and the menstruation status in female elite adolescent dancers.

Introduction: The grand jeté requires grace and proper biomechanics to produce the iconic glide through the air. Understanding how the preceding choreographed movements affect take-off and flight may influence teaching and training. We sought to examine the effects of 5 common preparatory approaches on grand jeté biomechanics. Methods: One male and 19 female dancers (19.3 ± 1.4 years; 1.61 ± 0.05 m; 58.1 ± 7.3 kg) with 12.5 ± 4.8 years of formal ballet experience performed grand jetés from run, chaine, chasse, assemble, and step-step approaches. Plié angle (deg), vGRF (BW), leap height (m), and leap distance (m) were measured with a motion analysis system and a force plate. One-way repeated measures ANOVAs were conducted to compare variables between approaches and Bonferroni tests were used for pairwise comparisons. Results: Plié depth, vGRF, leap height, and leap distance were all significantly different (P < .001). Plié angles (43.6-68.2 deg) were deepest for the assemble and shallowest for the run. vGRF (2.46-3.81 BW) were greatest for the assemble versus all but the run, and smallest for the chaine. Leap height (0.33-0.41 m) was highest for the run versus the chaine and step-step, but not versus assemble. Height was lowest for the chaine. Leap distance (0.24-1.03 m) was longest for the run and shortest for the assemble. Conclusions: The run approach optimizes the float through the air illusion (high leap height and distance) through applying high vGRF but moderate plié angles. The chasse approach is the next most optimal. The 2-legged assemble requires deeper plié angles to achieve height but produces shorter horizontal distances. Single leg plié training may enhance grand jeté performance and reduce injury risk from approaches such as the run, chaine, chasse, and step-step.Level of Evidence: Level 2.

Objective: To explore perspectives and experiences of adolescent ballet dancers in Australia in relation to dance-related injuries and their impact, injury risk factors, prevention, and treatment. Design: Adolescent ballet dancers aged from 12 to 19 years in Australia were invited to participate in an online qualitative survey. Methods: Responses to open-ended questions were analyzed thematically using grounded theory while quantitative information was summarized with descriptive statistics and triangulated with qualitative data. Results: Nineteen adolescent dancers reported experiencing pain and multiple injuries but hiding or ignoring injuries due to fear. Dancers recognized the significant physical and psycho-social impact of dance-related injuries on themselves and others. Several risks and injury prevention strategies were identified by dancers. Dancers perceived that treatments were not always informed or effective. Conclusion: Findings suggest that adolescent ballet dancers experience multiple dance-related injuries but require support to disclose injuries, participate in injury prevention, and access treatment. Health professionals may improve quality of care by increasing their understanding of ballet and providing specific management advice. Dance teachers may benefit from further education to support their students. Clinical trials are required to confirm or negate the validity of proposed injury risks and the effectiveness of injury prevention strategies and treatments.

Introduction: The primary aim of this study was to present descriptive heart rate (HR), heart rate recovery (HRR) and RPE data for the DAFT and HIDT within one sample of contemporary dance students. The second aim was to explore if objective (HR) and subjective (RPE) data were correlated between tests.

Method: 40 (11 males, 29 females) university dance students with a mean age of 18.8 ± 1.8 years performed the DAFT and HIDT on 2 separate occasions within 1 week. Measurements were HR after 4 minutes in all stages of the DAFT, the percentage of age-predicted maximal HR (%HR_max) of all stages of the DAFT and at the end of the HIDT, and peak HR (HR_peak) at the end of both tests. Subjective ratings of perceived exertion (RPE) and HR recovery after 1 minute of rest (HRR) were determined after the tests.

Results: HR_peak of the DAFT and HIDT were 188.1 ± 11.0 and 185.3 ± 7.3 beats·min^-1, respectively. There were high positive correlations between HR_peak of the HIDT and stages 3 to 5 of the DAFT (r = 0.716-0.740, all P-values < .01). HRR (r = .678, P < .01) and %HR_max (r = .746, P < .01) showed moderate to high correlations between the DAFT and HIDT. The anaerobic training zone was reached in stages 4 and 5 of the DAFT and at the end of the HIDT. The subjective RPE scores did not significantly correlate between DAFT and HIDT, neither with objective HR data.

Conclusion: Although the DAFT and HIDT differ in intensity and work-to-rest ratio, there were high correlations between HR and HRR data of both tests and both tests reached intensities above the anaerobic threshold (%HR_max > 85%).

Purpose: The Backalast^® compression jacket is intended to improve posture and proprioception of the trunk and shoulder girdle for dancers and dance students during dance training by way of elastic bands in the rear of the garment (which include bands enclosing the inferior thorax). This study was intended to investigate whether there is evidence to support those objectives. Materials and Methods: Fifteen dance students participated (4 male, mean age 19.9 ± 1.4 years old). The dependent variables of trunk-pelvis angle and proximity of trunk axis to global vertical for each participant were measured using optical motion capture before and after the completion of a series of trunk movements. The Helen Hayes model, which we used to represent the trunk, includes the shoulder girdles as part of the trunk. We compared the effect of the type of garment (Backalast^® or control compression shirt) worn upon the 2 dependent variables, within-subject with paired t-tests. The order of whether Backalast^® or control compression shirt was worn first was alternated between participants. Results: The pre/posttest difference in trunk proprioception as represented by the construct of ability to reproduce trunk-pelvis angle wearing the Backalast^® was 0.8° ± 0.8°, but for the control shirt, the difference was 1.8° ± 1.4°, P = .03. The difference between garments in vertical trunk alignment, measured after the series of trunk movements, was not significant. Conclusion: Our findings suggest that the Backalast^® can help enhance trunk proprioception when compared to the control compression shirt, although it did not change the angle at which the participants' held their trunks while standing erect (proximity to global vertical).