Effect of Reduced Stiffness Dance Flooring on Lower Extremity Joint Angular Trajectories During a Ballet Jump

The Effect of Foot Position and Lean Mass on Jumping and Landing Mechanics in Collegiate Dancers

The purpose of this study was to investigate the effects of foot positioning and lean mass on jumping and landing mechanics in collegiate dancers. Thirteen dancers performed 3 unilateral and bilateral vertical jumps with feet in neutral and turnout positions. Dual-energy x-ray absorptiometry scans, jump height, vertical stiffness, and joint stiffness were assessed for relationships between foot positions. Jump heights were greater in right compared with left limb (P = .029) and neutral compared with turnout (P = .020) during unilateral jumping. In unilateral landing, knee stiffness was greater in turnout compared with neutral (P = .004) during the loading phase. Jump height (P < .001) was significantly increased, and vertical stiffness (P = .003) was significantly decreased during bilateral jumping in neutral compared with turnout. Significantly increased hip stiffness during the attenuation phase was observed in neutral compared with turnout (P = .006). Left-limb lean mass was significantly less than the right limb (P < .05). Adjustments for bilateral jumping were focused on hip stiffness, whereas there was a slight shift to knee strategy for unilateral jump.

Sensing Technology for Assessing Motor Behavior in Ballet: A Systematic Review

Background

Human performance in classical ballet is a research field of growing interest in the past decades. Technology used to acquire data in human movement sciences has evolved, and is specifically being applied to evaluate ballet movements to better understand dancers’ profiles. We aimed to systematically review sensing technologies that were used to extract data from dancers, in order to improve knowledge regarding the performance of ballet movements through quantification.

Methods

PubMed, MEDLINE, EMBASE, and Web of Science databases were accessed through 2020. All studies that used motor control tools to evaluate classical ballet movements, and possible comparisons to other types of dance and sports movements were selected. Pertinent data were filled into a customized table, and risk of bias was carefully analyzed.

Results

Eighty studies were included. The majority were regarding classical ballet and with pre-professional dancers. Forty-four studies (55%) used two or more types of technology to collect data, showing that motion capture technique, force plates, electromyography, and inertial sensors are the most frequent ways to evaluate ballet movements.

Discussion

Research to evaluate ballet movements varies greatly considering study design and specific intervention characteristics. Combining two or more types of technology may increase data reliability and optimize the characterization of ballet movements. A lack of studies addressing muscle–brain interaction in dancers were observed, and given the potential of novel insights, further studies in this field are warranted. Finally, using quantitative tools opens the perspective of defining what is considered an elite dancer.

Impact attenuation and deformation characteristics of dance floors on jump kinematics

Specialist dance floors have been promoted to reduce impact forces and reduce lower limb injury for dancers. 18 trained female dancers carried out 70 continuous ballet jumps on 4 different surfaces wearing an XSENS suit. Three specialist dance floors, Floor A (64% force reduction), Floor B (67% force reduction), Floor C (no data) were compared to Floor D (vinyl-covered concrete - control). Dependent variables for each analysed jump (2,3,4, and 67,68,69) were ankle, knee, hip range of movement (ROM); lower and upper leg angular velocities and pelvis vertical acceleration. No main effects were reported for dance floor, first and last jump series. Comparison of the floors against Floor D reported a main effect for the dance floors (p=0.001), first and last jump series (p=0.001). Between-subject effects noted that ankle ROM was significantly greater for trials on floor A (p=0.007) compared to floor D. ROM data significantly decreased between the first and last jump series whilst vertical pelvis accelerations increased except for floor A. Within the current study, a foam backed vinyl floor (C) provided better shock absorption than floors with higher deformation characteristics (A and B) and none of the specialist dance floors performed better than vinyl covered concrete (D).

Prevalence and Risk Factors of Dance Injury During COVID-19: A Cross-Sectional Study From University Students in China

Objectives: Although coronavirus disease 2019 (COVID-19) has transformed the training environment of dancers worldwide, little is known on how this has affected injury prevalence, causes, and risk factors. Methods: An online investigation involving Chinese full-time dance students was conducted (September-November 2020), which covered two 6-month periods just before and during the first COVID-19 lockdown. Results: 2086 students (19 ± 2.4 years) responded to the investigation. Injury prevalence dropped from 39.6% (before the lockdown) to 16.5% (during the lockdown) (p < 0.01). It was noted that a significant increase in injury severity during the lockdown was caused due to a 4.1% increase in moderate-to-severe injuries (p < 0.05). During the lockdown, the injuries on the lower back, feet, and shoulders decreased significantly (p < 0.01), but the knee, ankle, and groin/hip joint injuries remained the same. Fatigue and the recurrence of an old injury remained as the top two perceived causes of an injury between the two periods with the increase in an unsuitable floor (p < 0.01), a cold environment (p < 0.05), and set/props (p < 0.05). The fatigue degree of students decreased (p < 0.01) and their hours of sleep increased (p < 0.01) during the lockdown. Binary Logistic Regression analysis indicated that dance injury is associated with fatigue, the hours of sleep, and the actions taken if they suspect an injury during the lockdown (p < 0.05), but is only related to the time set aside for a cooldown and age before the lockdown period (p < 0.05). Conclusion: Although injury prevalence dropped significantly during the first COVID-19 lockdown in Chinese dance students, the main dance injury characteristics remained the same. Decreased fatigue and longer hours of sleep could explain the aforementioned drop in injury prevalence during the lockdown.

Work-related floors as injury hazards - a nationwide pilot project analyzing floors in theatres and education establishments in Germany

BACKGROUND

An adequate dance floor is said to prevent injuries. On the basis of scientific research, numerous recommendations regarding an adequate dance floor have been developed. Up to the present, however, studies have still been lacking into how far these recommendations have already been implemented in theatres with regular dance productions and/or in-house dance ensembles. The aim of this study is to analyze a nationwide survey on dance floors of theatres and education establishments in Germany.

METHODS

A questionnaire-based survey on existence and type of floors in the various dance-related working areas was carried out at theatres and education establishments institutions (n = 86 institutions (n = 76 theatres, n = 10 education establishments). References as to region, size of dance ensembles and dance styles performed were created.

RESULTS

Of all education establishments, 75.3% were equipped with a sprung sub-floor in the ballet studios. In contrast, sprung sub-floors were only found in 29.7% of the working areas, the stage AND ballet studios in theatres. The percentage of theatres providing sprung sub-floors in all rooms used by dancers is even lower. Considering all dance-related work areas, larger ensembles (>30 dancers) were offered better conditions regarding floors than smaller ensembles (p > 0.001). No significant tendencies were found regarding regions or dance styles.

CONCLUSION

Recommendations concerning an appropriate dance floor have only partly been realized. Besides secured finances for reinstallation, further education of responsible officials and artists is essential. However, accrediting dance as own genre in theatres is the indispensable prerequisite.