The Physical Attributes Most Required in Professional Ballet: A Delphi Study

Classical Ballet for Women Aged Over 50 Years: Investigating Balance, Strength, and Range of Motion

Background: Regular exercise can mitigate the loss of strength, balance, and flexibility that contribute to age-related decline in physical function and mobility. However, traditional exercise interventions often report poor adherence rates. There is growing interest in classical ballet as an enjoyable exercise modality for adults in middle to late age. Classical ballet requires muscular strength, coordination, and flexibility. The current study investigated a classical ballet intervention on the balance, physical function, and range of motion of women aged over 50 years. Methods: Twenty-two healthy female participants (aged 56.2 (4.5) years (mean (SD)) completed a 10-week ballet intervention. Results: This single-arm study showed significant improvements (p<.05) in lower limb strength (measured by 5 times sit-to-stand and forward leap) and high adherence rates (95% adherence for participants who completed the intervention). No adverse events were reported. Improvements in balance were reported in the left leg only (as measured by center of pressure ellipse area in the parallel retiré condition). Conclusions: These results allude to the positive effects of ballet training on strength and balance in adults aged 50 years and over. High adherence rates suggest that ballet training was enjoyed and may thus be a long-term exercise modality for this population. Although this study was a single-arm design, it suggests promising results for future research wishing to evaluate the effectiveness of classical ballet training using randomized controlled trial designs.

Quantifying hierarchy and prestige in US ballet academies as social predictors of career success

In the recent decade, we have seen major progress in quantifying the behaviors and the impact of scientists, resulting in a quantitative toolset capable of monitoring and predicting the career patterns of the profession. It is unclear, however, if this toolset applies to other creative domains beyond the sciences. In particular, while performance in the arts has long been difficult to quantify objectively, research suggests that professional networks and prestige of affiliations play a similar role to those observed in science, hence they can reveal patterns underlying successful careers. To test this hypothesis, here we focus on ballet, as it allows us to investigate in a quantitative fashion the interplay of individual performance, institutional prestige, and network effects. We analyze data on competition outcomes from 6363 ballet students affiliated with 1603 schools in the United States, who participated in the Youth America Grand Prix (YAGP) between 2000 and 2021. Through multiple logit models and matching experiments, we provide evidence that schools' strategic network position bridging between communities captures social prestige and predicts the placement of students into jobs in ballet companies. This work reveals the importance of institutional prestige on career success in ballet and showcases the potential of network science approaches to provide quantitative viewpoints for the professional development of careers beyond science.

Is there an association between joint range of motion and muscle strength in young female dancers? And, does it depend on the effects of age and menarche?

Aiming to determine the association between joint range of motion (ROM) and muscle strength; and, the effect of age and menarche on those two factors; 132 pre-and post-menarche dancers, aged 12-14 years were assessed for joint ROM and for muscle strength at the hip, knee and ankle and foot joints. En-pointe ROM was significantly correlated with ankle plantar-flexors' (r = -.184) and with ankle dorsiflexors' muscle strength (r = -.221). Hip external rotation ROM was significantly correlated with knee extensors' strength (r = -.263). Pre-menarche dancers had higher joint ROM compared with post-menarche dancers; yet, dancers at post-menarche were stronger compared to dancers at pre-menarche. The slope coefficient was negative at the age of 12 in hip external rotation and in en-pointe (-0.80 and -0.52, respectively) and became steeper with age (age 13: -3.52 and -3.28, respectively; age 14: -6.31 and -4.42, respectively). Along maturation, dancers with high joints ROM showed reduced muscle strength. Pre-menarche dancers have higher joint ROM, yet reduced muscle strength, compared with post-menarche dancers. As the association between joint ROM and muscle strength might be involved with growth and development, young dancers should be screened along pubertal stages in order to decide the correct curricula and to prevent future injuries.

Dancers with non-specific low back pain have less lumbar movement smoothness than healthy dancers

BACKGROUND

Ballet is a highly technical and physically demanding dance form involving extensive end-range lumbar movements and emphasizing movement smoothness and gracefulness. A high prevalence of non-specific low back pain (LBP) is found in ballet dancers, which may lead to poor controlled movement and possible pain occurrence and reoccurrence. The power spectral entropy of time-series acceleration is a useful indicator of random uncertainty information, and a lower value indicates a greater smoothness or regularity. The current study thus applied a power spectral entropy method to analyze the movement smoothness in lumbar flexion and extension in healthy dancers and dancers with LBP, respectively.

METHOD

A total of 40 female ballet dancers (23 in the LBP group and 17 in the control group) were recruited in the study. Repetitive end-range lumbar flexion and extension tasks were performed and the kinematic data were collected using a motion capture system. The power spectral entropy of the time-series acceleration of the lumbar movements was calculated in the anterior-posterior (AP), medial-lateral (ML), vertical (VT), and three-directional (3D) vectors. The entropy data were then used to conduct receiver operating characteristic curve analyses to evaluate the overall distinguishing performance and thus cutoff value, sensitivity, specificity, and area under the curve (AUC) were calculated.

RESULTS

The power spectral entropy was significantly higher in the LBP group than the control group in the 3D vector in both lumbar flexion and lumber extension (flexion: p = 0.005; extension: p < 0.001). In lumbar extension, the AUC in the 3D vector was 0.807. In other words, the entropy provides an 80.7% probability of distinguishing between the two groups (i.e., LBP and control) correctly. The optimal cutoff entropy value was 0.5806 and yielded a sensitivity of 75% and specificity of 73.3%. In lumbar flexion, the AUC in the 3D vector was 0.777, and hence the entropy provided a probability of 77.7% of distinguishing between the two groups correctly. The optimal cutoff value was 0.5649 and yielded a sensitivity of 90% and a specificity of 73.3%.

CONCLUSIONS

The LBP group showed significantly lower lumbar movement smoothness than the control group. The lumbar movement smoothness in the 3D vector had a high AUC and thus provided a high differentiating capacity between the two groups. It may therefore be potentially applied in clinical contexts to screen dancers with a high risk of LBP.

Plantar Venous Pump Activity, Generalized Joint Hypermobility, and Foot Mobility in Ballerinas: A Case-Control Study

CONTEXT

The plantar venous pump (PVP) is a vascular network located between the muscles of the foot arch. It has been suggested foot mobility is critical for PVP activation.

OBJECTIVE

This study investigates the effect of generalized joint hypermobility (GJH) on foot mobility and PVP activity in ballerinas and to determine how a short-term warm-up exercise impacts these parameters in the presence of GJH.

DESIGN

Prospective study.

METHODS

Twelve ballerinas (age = 16.73 [1.8] y) and 15 non-dancer-matched controls (age = 16.31 [2.1] y) were included. When performing weight-bearing activities, venous return parameters (diameter, velocity, and flow volume) from the posterior tibial vein were measured using color and spectral Doppler ultrasonography. Foot mobility was determined using navicular drop test. The participants performed a 10-minute cycling exercise to reveal its effect on reducing tissue stiffness. All measurements were performed synchronously and twice-before and after the cycling exercise.

RESULTS

The results showed the navicular height obtained before and after exercise in the ballerinas was significantly different compared with that obtained in the sitting position, and the values obtained in the 3 measurement positions in the nondancer group were significantly different from each other (P < .05). The difference between the venous diameter values measured before and after exercise and the reference value was significant in both groups (P < .001). There was a significant decrease in venous velocity following exercise in the nondancer group (P = .044). The venous volume values obtained after exercise were significantly different between the groups (P = .039).

CONCLUSIONS

The GJH has no distinctive effect on foot mobility and PVP activity in ballerinas. The presence of GJH did not influence the effect of short-term warm-up exercise on foot mobility and PVP activity. We believe that measuring the navicular drop and venous return with a more precise synchronization may provide additional information regarding the link between arch tension and venous return.

Player Profiling and Monitoring in Basketball: A Delphi Study of the Most Important Non-Game Performance Indicators from the Perspective of Elite Athlete Coaches

BACKGROUND

Little is known about which indicators of performance elite athlete coaches (i.e., professional coaches who coach at the national or international levels) consider to be important for basketball.

OBJECTIVE

Using a Delphi procedure, the aim of this study was to identify the non-game performance indicators elite athlete coaches consider to be important for the recruitment/selection of basketball players.

METHODS

Ninety elite athlete coaches (basketball coaches (n = 71) and strength/conditioning coaches (n = 19) who coached men (n = 60), women (n = 23), or both (n = 7)), employed in 23 countries across six continents, participated in a three-round online Delphi survey. Round 1 asked coaches to identify the non-game performance indicators (i.e., measures other than game statistics) they currently used (or would like to use) for player recruitment/selection, with common indicators combined into single indicators. Round 2 asked coaches to rate the importance of each performance indicator using a Likert scale (range: 0 = no importance whatsoever to 10 = extremely important). Round 3 asked coaches to identify the single best test measure for each indicator rated ≥ 6 (i.e., important to extremely important) in Round 2. Results were reported descriptively.

RESULTS

A total of 608 responses (344 after removal of duplicates) were reported in Round 1, which were collapsed into 35 indicators, all of which were rated as 'important' in Round 2. Psychological and game intelligence indicators were typically rated as very important to extremely important (i.e., median = 9), with physical fitness and movement skills typically rated as very important (i.e., median = 8). For most indicators, coach observation was identified as the best test measure, with unique objective performance/anthropometric tests identified for all physical fitness indicators.

CONCLUSION

This study identified a range of psychological, game intelligence, physical fitness, and movement skill indicators that were considered by elite athlete coaches to be important to extremely important for the recruitment/selection of basketball players. These findings may inform the development of a basketball-specific test battery for recruiting/selecting and monitoring players.

Joint Hypermobility Does Not Increase the Risk of Developing Hip Pain, Cartilage Defects, or Retirement in Professional Ballet Dancers Over 5 years

OBJECTIVE

This study aimed to evaluate the risk of developing hip pain, cartilage defects, and retirement in hypermobile ballet dancers over 5 years.

DESIGN

Prospective cohort study.

SETTING

Professional Ballet Company.

PARTICIPANTS

Forty ballet dancers (57.5% women) were assessed at baseline and 21 dancers at 5 years.

INDEPENDENT VARIABLE

Baseline evaluation of generalised joint hypermobility (GJH) (GJH = Beighton score ≥5/9).

OUTCOME MEASURES

Cartilage defects on hip 3T magnetic resonance imaging and pain (the Copenhagen Hip and Groin Outcome Score: HAGOS) at baseline and follow-up, hip-related injury incidence, and retirement over 5 years.

RESULTS

Twelve dancers retired by follow-up, none due to hip injury or GJH. At baseline, 17 (42.5%) dancers were hypermobile, 18 (45%) had cartilage defects, and 15 (37.5%) reported hip pain (HAGOS pain <100). Cartilage defect prevalence was lower in GJH (n = 1) than non-GJH dancers (n = 17, P < 0.001). Beighton scores <5/9 were predictive of cartilage defect presence at baseline, independent of age and sex (P = 0.006). At follow-up, cartilage defects progressed in 2 dancers, one was hypermobile. Baseline and follow-up HAGOS pain scores were similar in GJH and non-GJH dancers (P > 0.05 for all). Hip-related injury over 5 years was reported by a similar number of GJH (n = 7) and non-GJH dancers (n = 6, P = 0.7). Hypermobility was more prevalent in active dancers (n = 12) than dancers who retired (n = 2), independent of age, rank, and sex (P = 0.03).

CONCLUSIONS

Hypermobile dancers are at no greater risk of reporting hip pain and injury or retirement over 5 years, and cartilage defect prevalence was much lower in GJH than non-GJH dancers.

The physical characteristics underpinning performance of wheelchair fencing athletes: A Delphi study of Paralympic coaches

Wheelchair fencing (WF) is a Paralympic sport which is practised by athletes with physical disabilities and is classified into three categories according to the degree of activity limitation the impairment causes in the sport. All Paralympic sports are requested to develop their own evidence-based classification system to enhance the confidence in the classification process; however, this is yet to be achieved in WF. Research within WF is scarce; therefore, the aim of this study was to reach expert consensus on the physical characteristics that underpin performance of athletes competing in the sport as this is known as one of the initial steps required to achieve an evidence-based classification system. Sixteen Paralympic WF coaches were invited to take part in a three-round Delphi study, with experts drawing consensus on qualities of speed, strength, power, flexibility and motor control of the trunk and fencing arm being associated with increased athletic success. The required qualities of the non-fencing arm led to diverging opinions across the expert panel. This study provides clear guidance of the physical qualities to be developed to maximize athletic performance while also providing the initial framework to guide future WF classification research.

Choreography-Specific Cross-Training and Conditioning Programs

Because of increased choreographic demands, early specialization, multi-genre dancers, and high incidence of career-ending injuries, there is a need for enhanced training methodologies to address the unique needs of today's professional dancer. It is imperative for company directors, instructors, choreographers, and dance medicine practitioners to consider implementing the most specific conditioning and training programs to prepare their dancers to meet or exceed expectations without resultant injury. Quantifying effectiveness of choreography-specific training programs is an area for further research. The implementation of scientific principles can and should be used to enhance dancers' health, performance, athleticism, and artistry.

Isometric exercises and somatosensory training as intervention programmes for patellofemoral pain in young dancers

Patellofemoral pain (PPF) is a common problem experienced by young dancers. Currently, there is no clear indication as to the optimal intervention programme for reducing the level of pain and improving functional abilities in young dancers with PFP. Our aim was to examine the efficacy of two intervention programmes compared with controls in relation to PFP symptoms (shown by pain level, Grinding test, and patellar inhibition test-PIT) and functional abilities of dancers with PFP. Ninety-eight young dancers (mean age 13.4 ± .97) with PFP were assessed for clinical parameters and functional abilities pre and post an intervention programme lasting 12 weeks. Using cluster sampling controlling for grade and school, the dancers were divided into three groups: isometric exercises (IE), somatosensory training (ST), and control (CO). Post-intervention, significantly lower pain levels upon patellar provocation testing were reported for the two treatment groups compared with controls. There was a significantly lower rate of legs recovered in the CO group compared with both intervention groups on the Grinding test, and on the PIT. Postural balance ability and proprioception abilities were significantly better post-treatment for the two treatment groups compared with controls. A significant interaction showed that hip abduction muscle strength improved more in the IE group. In conclusion, both isometric exercises and somatosensory training were effective for decreasing clinical symptoms and improving some functional abilities in young dancers with PFP. Further studies on these types of interventions could determine the most effective training protocol for prevention and treatment of PFP in young dancers.