Differences of ballet turns (pirouette) performance between experienced and novice ballet dancers

Differences in the Rotation Axis Between Professional and Experienced Amateur Ballet Dancers During pirouette en dehour in Classical Ballet With Wearing Pointe Shoes: A Pilot Study

Introduction: En pointe, in which weight is placed on the tiptoes, is a fundamental practice for female ballet dancers with pointe shoes. The center of mass (COM) is maintained over the base of support and the relative position of COM to the center of pressure (COP) is especially important when conducting a pirouette in ballet. A pirouette is a fundamental turn in classical ballet with flat shoes and pointe shoes. The investigation of the turn with pointe shoes would be favorable for understanding the movement with limited base of support. Herein, we aimed to determine the differences in the ability to perform pirouettes with pointe shoes between professional and amateur ballet dancers. Methods: This study included 8 professional and 9 amateur ballet dancers. The dancers performed a single pirouette, and the movement was captured and analyzed in 3 phases: turning with double-leg support (TDS), turning with single-leg support in pre-swing (TSSp), and turning with single-leg support in mid-swing (TSSm). The analysis focused on the inclination between the vertical angle and the COP-COM line, the vertical maximum reaction force, and the jump-up time in each phase. Results: The results showed no significant differences between the TDS and TSSp. However, professional ballet dancers exhibited significantly lesser posterior inclinations (professional; 2.05° ± 0.90°, amateur; 3.88° ± 1.67°) and jump-up time (professional; 0%, amateur; 1.4% ± 1.3%) than amateur dancers during TSSm. Conclusion: Overall, the findings suggest that professional dancers exhibit superior control skills regarding the COP-COM line than amateur dancers during TSSm. These results may be attributed to the fact that professional dancers can maintain the COM as close to the upright as on the COP without jumping during TSSm. This enables professional dancers to conduct the movements esthetically and continue on to the other movements in the dance phase.

Does a visual reference help ballet dancers turn more successfully?

In dance, performing multiple rotations around the longitudinal axis is a complex task that can only be accomplished proficiently by highly skilled dancers. However, this extraordinary skill has been investigated sparsely. The few studies to date have focused on the biomechanical analysis of ballet rotations. However, none have investigated the influence of visual information on continuous rotations, such as Fouettés or à la Seconde turns. Therefore, the present study aims to examine the role of a visual reference on balance control and the dance-specific head coordination - spotting - during turning performance of highly skilled ballet dancers. To this end, 12 participants performed 12 Fouettés (females) or à la Seconde turns (males) with and without a visual reference. As dependent measures, we analysed balance control (i.e., supporting foot path length), spotting duration, head isolation, and orientation (i.e., deviation of pelvis from the front). A linear mixed model was performed to analyse the influence of the visual conditions overall and over the continued performance of 12 consecutive rotations. The results revealed that overall, path length was significantly smaller in the condition without a visual reference. Spotting duration and head isolation did not differ significantly between conditions. Moreover, dancers oriented themselves better towards the front in the condition with a visual reference. When looking closer into the progression of performance over each consecutive rotation, highly skilled ballet dancers significantly decreased the supporting foot path length, and improved orientation when turning with a visual reference. On the other hand, without a visual reference, the dancers increased the spotting duration over time. Additionally, dancers increased head isolation towards the end of the turns in both conditions. These findings suggest that a visual reference helps ballet dancers sustain performance of consecutive rotations, mainly in optimising balance control and orientation. Thus, the more rotations a ballet dancer must turn, the more relevant a visual reference becomes for sustaining successful performance.

Applications of Biomechanical Foot Models to Evaluate Dance Movements Using Three-Dimensional Motion Capture: A Review of the Literature

Dance movement requires excessive, repetitive range of motion (ROM) at the foot-ankle complex, possibly contributing to the high rate of injury among dancers. However, we know little about foot biomechanics during dance movements. Researchers are using three-dimensional (3D) motion capture systems to study the in vivo kinematics of joint segments more frequently in dance-medicine research, warranting a literature review and quality assessment evaluation. The purpose of this literature review was to identify and evaluate studies that used 3D motion capture to analyze in vivo biomechanics of the foot and ankle for a cohort of dancers during dance-specific movement. Three databases (PubMed, Ovid MEDLINE, CINAHL) were accessed along with hand searches of dance-specific journals to identify relevant articles through March 2020. Using specific selection criteria, 25 studies were identified. Fifteen studies used single-segment biomechanical foot models originally created to study gait, four used a novel two-segment model, and six utilized a multi-seg- ment foot model. Nine of the studies referenced common and frequently published gait marker sets and four used a dance-specific biomechanical model with purposefully designed foot segments to analyze the dancers' foot and ankle. Description of the biomechanical models varied, reducing the reproducibility of the models and protocols. Investigators concluded that there is little evidence that the extreme total, segmental, and inter-segmental foot and ankle ROM exerted by dancers are being evaluated during dance-specific movements using 3D motion capture. Findings suggest that 3D motion capture is a robust measurement tool that has the capability to assist researchers in evaluating the in vivo, inter-segmental motion of the foot and ankle to potentially discover many of the remaining significant factors predisposing dancers to injury. The literature review synthesis is presented with recommendations for consideration when evaluating results from studies that utilized a 3D biomechanical foot model to evaluate dance-specific movement.

Learn to Turn: Does Spotting Foster Skill Acquisition in Pirouettes?

Purpose: The spotting technique (i.e., independent head from torso movement) has been revealed as the single feature that differentiates highly skilled from less-skilled dancers. In the current intervention study, the potential of a specific spotting training in novice dancers for learning double pirouettes was tested. Method: Novice dancers trained pirouettes in an experimental group and an active control group over a period of eight weeks by receiving either specific spotting instructions or technical instructions only. Pirouette performance was examined in a pretest, and a one-week-delayed retention test. In a further control test, effects of explicitly instructing how to perform the pirouettes (i.e., either with or without spotting) were investigated. Results: Different than expected, in the retention test, only few participants from the experimental group showed the spotting technique. Moreover, the spotting group did not perform better than the control group. Rather, the balance measure revealed that, while the control group improved over learning, the experimental group remained at the baseline values and showed a slight advantage for orientation only. In the control test, all groups showed inferior performance as compared to the retention test. Conclusion: In sum, the current findings show that-at least for beginners-the spotting technique is not suitable to be implemented in applied training settings. Moreover, in line with the expert performance approach, this study suggests to investigate the implementation of expert skills in applied training routines experimentally.

Defining Spotting in Dance: A Delphi Method Study Evaluating Expert Opinions

Spotting is a typical isolated head coordination used by many dancers during rotation. However, with sporadic and inconclusive explanations as to why dancers spot, the critical characteristics and functionalities of spotting have yet to be identified. Therefore, a Delphi method survey was used as a novel methodology for providing greater insights into this under-examined motor behavior, bringing together experts from various disciplines to generate ideas and identify the crucial elements of spotting. Following the selection of experts, three rounds of data collection and analysis were conducted to narrow down relevant topics and evaluate consensus. To gather opinions in Round 1, experts were asked to respond freely to three prompts regarding the reasoning, characteristics, and uses of successfully spotting; responses were then grouped into predominant items. To rate agreement in Round 2, experts rated their agreement on the relevance of the grouped items from Round 1 on a 5-point Likert scale; items rated 4 or 5 by at least 70% of the experts were taken as those consensually relevant to the group. To rank importance in Round 3, Best-Worst Scaling was used to determine individual rankings of the relevant items from Round 2. In a series of comparisons, experts were prompted to select the most and least important items in multiple sub-groupings. Group mean ranking of items as well as ranking concordance and differentiation were analyzed to determine the most important items and the strength of consensus, respectively. Overall, consensus and differentiation in experts’ item rankings were low; however, novel insights were presented. As characteristics of successfully spotting, experts emphasized head isolation, timing, and gaze specificity alongside functional characteristics, substantiating spotting as purposeful action in rotation. Building on traditional notions of spotting for reduced dizziness and maintaining balance, successfully spotting was further deemed useful for multiple turns, orientation, and rhythm. The findings of this study thus provide informed guidelines for future analysis and training of this complex head coordination in rotations.

Internal and Imagined External Foci of Attention Do Not Influence Pirouette Performance in Ballet Dancers

Ballet dancers need to constantly improve their performance. Several studies show that an internal focus (on body movements) leads to inferior motor performance relative to an external focus of attention (on the movement effects), but the majority of dancers usually adopt an internal focus. It is not clear if the benefits of an external focus are relevant for form-based tasks performed in a ballet. Purpose: Test whether an imagined external focus of attention can improve ballet dancers' performance of a form-based task, the en dehors double pirouette (EDDP). Method: 23 experienced amateurs and 17 professional dancers between 18 and 35 years old performed three EDDP under each of three attentional focus instruction conditions (No Focus, Internal, Imagined External). Order of presentation of Internal and Imagined External focus instructions was blocked and balanced across participants. Movement quality was assessed by three experts with a customized observational scale. Movement kinematics were measured by the angle of inclination of the trunk and inclination of the rotation axis with respect to the global vertical during the EDDP. Results: Movement quality and trunk inclination were significantly different between amateurs and professionals, but the rotation axis inclination was not. No quantitative or qualitative effects of focus were found for the performance of the EDDP across focus conditions. Conclusions: There appears to be no differential effects of using an internal or imagined external focus on the immediate performance of the EDDP for amateur and professional ballet dancers. Personal and task factors might account for the lack of effects.

Do Grade II Ankle Sprains Have Chronic Effects on the Functional Ability of Ballet Dancers Performing Single-Leg Flat-Foot Stance? An Observational Cross-Sectional Study

Ballet dancers have a higher risk than the general population of ankle sprains. Ankle proprioception is of the utmost importance for executing static and dynamic positions typical of ballet dancing. Ankle sprains can create changes in functional ability that may affect ballet performance. The aim of this cross-sectional observational study is to evaluate if non-professional ballet dancers that were previously injured with a grade II ankle sprain carry a long-term stability deficit in ballet specific positions (passé, arabesque) and in single-leg flat-foot stance, thereby affecting ballet performance. We enrolled 22 amateur female ballet dancers, 11 who previously had a grade II ankle injury and 11 who had no history of ankle injury. Stabilometric data (Center of Pressure Speed and Elipse Area) were assessed with the postural electronic multisensory baropodometer in normal, arabesque, and passè positions with both open and closed eyes. Using an unpaired t-test, we compared healthy and pathological feet of the ankle injury group for a standard monopodalic position and two ballet-specific positions. No difference between pathological and healthy feet of non-professional ballet dancers who suffered grade II ankle injury was detected. According to the parameters considered in this study, grade II ankle sprains seem to have a favorable prognosis in the sample that we evaluated.

Kinematic Analysis of Postural Stability During Ballet Turns (pirouettes) in Experienced and Novice Dancers

Turning is an important but difficult movement, often performed in ballet choreography. Understanding the postural sway during ballet turns is beneficial to both dancers and dance teachers alike. Accordingly, this study evaluated the postural sway angle during ballet turns in female novice and experienced ballet dancers by means of the inclination angle, determined from the center of mass (COM) and center of pressure (COP). Thirteen experienced dancers and 13 novice dancers performed ballet turns (pirouettes). The COM-COP inclination angle was measured during the preparatory, double-leg support, and single-leg support phases of the turn. The novice dancers exhibited significantly greater ranges of the COM-COP inclination angle in the anterior-posterior (AP) and medial-lateral (ML) directions during the preparatory (AP direction, p < 0.001; ML direction p = 0.035), double-leg support (AP direction p < 0.038; ML direction p = 0.011), and ending phases (AP direction p < 0.001; ML direction p = 0.024). Moreover, during the preparatory phase, the novice dancers failed to adjust their posture in a timely manner, and therefore showed overshooting errors. Finally, during the ending phase, the novice dancers showed a greater standard deviation of the COM-COP inclination angles and performed continual postural adjustments, leading to a less smooth movement than the experienced dancers. In conclusion, the novice dancers were suggested to focus on the COM-COP adjustment during both preparatory and ending phases.

Standing balance of professional ballet dancers and non-dancers under different conditions

Ballet training has been reported to positively influence balance ability. It is not entirely clear how improved balance ability manifests under standing conditions with different demands on postural control. The aim of the study was to compare balance of ballet dancers and non-dancers in a unipedal stance under different conditions. Twenty-five professional ballet dancers and twenty-five controls completed four unipedal standing balance tests: firm surface with eyes open and closed; foam mat surface with eyes open; and firm surface with eyes open immediately after performing ten 360° whole-body turns. The centre of pressure (COP) data were obtained with a force platform and the direction-specific standard deviations, velocities, and sample entropy of the COP displacement were computed. A three-way analysis of variance was used to compare groups, genders, and conditions. For standing immediately after performing ten turns, the postural sway parameters were significantly larger in the control group compared to the ballet dancers in both men and women. In this stance condition the values of postural sway and COP velocities in the control group were larger in the men compared to the women. For both genders in the control group all postural sway and COP velocity parameters were larger in standing with eyes closed and standing after performing 10 turns compared to standing with eyes open on both firm and foam surface. In the ballet dancers all COP velocity parameters were larger in standing with eyes closed compared to all other conditions. The results from the present study indicate that professional ballet dancers do not have a better general balance ability than untrained subjects.

Specificity of Postural Control: Comparing Expert and Intermediate Dancers

The expert-novice approach is inappropriate for studying postural control in sport and dance when novices are completely unable to perform relevant postural tasks and experts cannot demonstrate specific skills on everyday postural tasks. We tested expertise-specific differences on 6 static everyday and 5 dynamic dance-like postural tasks of varying difficulty in 13 professional and 12 intermediate nonprofessional dancers. Results showed a clear expert advantage on sway area for dance-like postural tasks, but not for static everyday tasks. This effect was also found for the control parameter of root mean square (RMS) velocity and partly for RMS amplitude of the difference signal between CoP and CoG line location. Results indicate that the expert advantage is task-specific and deliver new insights into the specificity of experts' postural performance.

Regulation of hip joint kinetics for increasing angular momentum during the initiation of a pirouette en dehors in classical ballet

This study examined how dancers regulate the hip joint kinetics to coordinate the upper and lower body angular momenta with the increased rotation of pirouette en dehors (pirouette) during the preparation. During the preparation of the pirouette, the upper body rotates greatly about the vertical axis; however, the lower extremity remains relatively stationary. Therefore, there must be specific control at the hip to coordinate the upper and lower body angular momenta in turns of increased rotation. Kinematics and kinetics of single to quadruple pirouettes performed by eight ballet dancers were analysed using a motion capture system and force plates. Peak angular momentum of the upper body around the vertical axis increased from the single to the quadruple pirouettes. The vertical components of hip abductor torque of the anterior lower limb and hip adductor and flexor torques of the posterior lower limb contributed to generating the clockwise moment acting on the upper body around the vertical axis, which was reduced by the vertical components of the hip internal and external rotator torques. Thigh flexion angles of the posterior and anterior lower limbs, respectively, at the peak adductor and abductor torques at the corresponding hip joints changed with the number of revolutions and changed the percent contribution of the relevant hip joint torques about the vertical axis. The results suggest that dancers need to regulate hip joint torques along with the thigh angles in the pirouettes depending on the number of revolutions.