Injury, Strength, and Jumping in Professional Ballet

Jumping and landing activities are the most common mechanism of injury in professional ballet dancers. There is limited evidence, however, that has elucidated the moderators of load experienced when jumping and landing in ballet. This thesis aimed to describe injury epidemiology, establish reliable methods of assessing strength and jumping, and explore the factors that may influence lower extremity load during jump landings in professional ballet dancers. A five-year injury epidemiology study revealed an incidence of medical attention and time-loss injuries of ~3–4 and ~1 per 1000 h of exposure, respectively. The mechanism of injury was jumping and landing activities in ~30–40% of time loss injuries. A systematic review found limited evidence that ballet dancers demonstrate externally rotated lower extremities, extended lower extremities prior to landing, and ankle-dominant jumping strategies. Two methodological studies established the within- and between-session reliability of vertical ground reaction force (vGRF) across several maximal isometric force tests and three-dimensional ankle mechanics during landing in turnout and parallel foot positions. The reliability of vGRF during maximal isometric force tests across the squat, standing plantarflexion, and seated plantarflexion positions demonstrated excellent reliability (intraclass correlation coefficients (ICC): 0.92–1.00) and low variability (coefficient of variation (CV): 2.0–6.5%). Three-dimensional ankle mechanics demonstrated within- (ICC: 0.17–0.96; CV: 1.4¬–82.3%) and between-session (ICC: 0.02–0.98; CV:1.3–57.1%) reliability ranging from poor to excellent, with, ankle excursion, peak ankle angle, and jump height demonstrating the greatest ICC values (ICC: 0.65–0.96; CV: 1.4–57%). The final two studies investigated jump landings in professional ballet dancers. A linear discriminate analysis revealed that three-dimensional ankle mechanics could discriminate different ballet foot positions, such that jump landings in fourth and fifth positions required a greater range of motion and ankle joint power when compared to other foot positions. Lastly, two linear mixed-effects models indicated that peak ankle joint moments and vGRFs have poor associations with strength, ankle dorsiflexion range of motion, and three-dimensional ankle excursions (R2: 0.01–0.02). Sex, foot position, and individual variation are more appropriate factors to consider when assessing the load experienced at a joint or system level. This thesis provides a thorough insight into injury, strength, and jumping in professional ballet dancers. To that end, this thesis has identified burdensome injuries and their mechanisms in professional ballet dancers alongside practical and reliable strategies to measure the physical attributes that may moderate the load experienced by a dancer upon landing

The activity demands and physiological responses observed in professional ballet: A systematic review

The aim of this study was to systematically review research into the activity demands and physiological responses observed in professional ballet. PubMed, Web of Science, SPORTDiscus, and ProQuest were searched for original research relating to 1) the session- specific activity demands of professional ballet, 2) the general activity demands of professional ballet, 3) the immediate physiological responses to professional ballet, or 4) the delayed physiological responses to professional ballet. From an initial 7672 studies, 22 met the inclusion criteria. Methodological quality was assessed using the Mixed Methods Appraisal Tool and a modified Downs and Black Index. Professional ballet is intermittent; however, activity characteristics and intensity vary by session type and company rank. Performances involve high volumes of jumps (5.0 ± 4.9 jumps·min-1), pliés (11.7 ± 8.4 pliés·min-1), and lifts (men - 1.9 ± 3.3 lifts·min-1), which may result in near-maximal metabolic responses. Ballet classes are less metabolically intense than performance during both barre and centre ( 5 h·day-1), but half is spent at intensities below 3 METs. Evidence is mixed regarding the delayed physiological responses to professional ballet; however, metabolic and musculoskeletal adaptations are unlikely to occur from ballet alone. The mean Downs and Black score was 62%. Appraisal tools revealed that a lack of clarity regarding sampling procedures, no power calculation, and a poor quality of statistical analysis were common limitations of the included studies. Given the large working durations and high rates of jumps, pliés, and lifts, managing training loads and recovery may be a focus for strategies seeking to optimize dancer health and wellbeing. Ballet companies should provide dancers with opportunities and resources to engage in supplementary physical training. Further research is required into the physical demands of rehearsals and the longitudinal training loads undertaken by professional ballet dancers

Epidemiological Characteristics of Foot and Ankle Injuries in 2 Professional Ballet Companies: A 3-Season Cohort Study of 588 Medical Attention Injuries and 255 Time-Loss Injuries.

The foot and ankle are often reported as the most common sites of injury in professional ballet dancers; however, epidemiological research focusing on foot and ankle injuries in isolation and investigating specific diagnoses is limited. To investigate the incidence rate, severity, burden, and mechanisms of foot and ankle injuries that (1) required visiting a medical team (medical attention foot and ankle injuries; MA-FAIs) and (2) prevented a dancer from fully participating in all dance-related activities for at least 24 hours after the injury (time-loss foot and ankle injuries; TL-FAIs) in 2 professional ballet companies. Descriptive epidemiological study. Foot and ankle injury data across 3 seasons (2016-2017 to 2018-2019) were extracted from the medical databases of 2 professional ballet companies. Injury-incidence rate (per dancer-season), severity, and burden were calculated and reported with reference to the mechanism of injury. A total of 588 MA-FAIs and 255 TL-FAIs were observed across 455 dancer-seasons. The incidence rates of MA-FAIs and TL-FAIs were significantly higher in women (1.20 MA-FAIs and 0.55 TL-FAIs per dancer-season) than in men (0.83 MA-FAIs and 0.35 TL-FAIs per dancer-season) (MA-FAIs, = .002; TL-FAIs, = .008). The highest incidence rates for any specific injury pathology were ankle impingement syndrome and synovitis for MA-FAIs (women 0.27 and men 0.25 MA-FAIs per dancer-season) and ankle sprain for TL-FAIs (women 0.15 and men 0.08 TL-FAIs per dancer-season). work and jumping actions in women and jumping actions in men were the most common mechanisms of injury. The primary mechanism of injury of ankle sprains was jumping activities, but the primary mechanisms of ankle synovitis and impingement in women were related to dancing . The results of this study highlight the importance of further investigation of injury prevention strategies targeting work and jumping actions in ballet dancers. Further research for injury prevention and rehabilitation strategies targeting posterior ankle impingement syndromes and ankle sprains are warranted. [Abstract copyright: © The Author(s) 2023.

Dance Exposure, Individual Characteristics, and Injury Risk over Five Seasons in a Professional Ballet Company

PURPOSE: To describe the relationships between dance exposure, dancer characteristics, and injury risk across five seasons in a professional ballet company. METHODS: Dance exposure time and clinician-reported time-loss and medical attention injury data were prospectively collected from 118 professional dancers of The Royal Ballet between 2015/16 and 2019/20. Cox proportional hazards and shared frailty models were fitted to overuse and traumatic injuries; individualized robust Z-scores for 7-day and 28-day accumulated exposure, and week-to-week change in exposure, age, sex, company rank, and injury history were included as time-varying covariates. RESULTS: Across 381,710 h of exposure, 1332 medical attention and 427 time-loss injuries were observed. Positive relationships were observed between week-to-week change in exposure and overuse time-loss (+1 Z-score hazard ratio (HR): 1.27, 95% confidence interval (CI): 1.06-1.53) and medical attention injury risk (+1 Z-score HR: 1.17, 95% CI: 1.06-1.28). A negative relationship was observed between 7-day accumulated exposure and overuse medical-attention injury risk (+1 Z-score HR: 0.74, 95% CI: 0.66-0.84). Overuse time-loss injury risk was greater in soloists compared to the corps de ballet (HR: 1.47, 95% CI: 1.01-2.15), and in dancers with a higher previous injury rate (+1 injury.1000 h-1 HR: 1.06, 95% CI: 1.02-1.10). Only age was associated with traumatic time-loss (+1-year HR: 1.05, 95% CI: 1.01-1.09) or medical attention injury risk (+1-year HR: 1.04, 95% CI: 1.01-1.07). CONCLUSION: Professional ballet companies should implement training principles such as periodization and progression, particularly in the case of senior-ranking dancers, older dancers, and dancers with high rates of previous injury. These findings provide a basis for future prospective investigations into specific causal injury pathways

Injury epidemiology in professional ballet: a five-season prospective study of 1596 medical attention injuries and 543 time-loss injuries

OBJECTIVES: To describe the incidence rate, severity, burden and aetiology of medical attention and time-loss injuries across five consecutive seasons at a professional ballet company. METHODS: Medical attention injuries, time-loss injuries and dance exposure hours of 123 professional ballet dancers (women: n=66, age: 28.0+/-8.3 years; men: n=57, age: 27.9+/-8.5 years) were prospectively recorded between the 2015/2016 and 2019/2020 seasons. RESULTS: The incidence rate (per 1000 hours) of medical attention injury was 3.9 (95% CI 3.3 to 4.4) for women and 3.1 (95% CI 2.6 to 3.5) for men. The incidence rate (per 1000 hours) of time-loss injury was 1.2 (95% CI 1.0 to 1.5) for women and 1.1 (95% CI 0.9 to 1.3) for men. First Soloists and Principals experienced between 2.0-2.2 additional medical attention injuries per 1000 hours and 0.9-1.1 additional time-loss injuries per 1000 hours compared with Apprentices (p</=0.025). Further, intraseason differences were observed in medical attention, but not time-loss, injury incidence rates with the highest incidence rates in early (August and September) and late (June) season months. Thirty-five per cent of time-loss injuries resulted in over 28 days of modified dance training. A greater percentage of time-loss injuries were classified as overuse (women: 50%; men: 51%) compared with traumatic (women: 40%; men: 41%). CONCLUSION: This is the first study to report the incidence rate of medical attention and time-loss injuries in professional ballet dancers. Incidence rates differed across company ranks and months, which may inform targeted injury prevention strategies

The Validity of the Session Rating of Perceived Exertion Method for Measuring Internal Training Load in Professional Classical Ballet Dancers

The aim of this study was to investigate the convergent validity of session rating of perceived exertion (s-RPE) with objective measures of internal training load in professional classical ballet dancers. Heart rate and s-RPE data were collected in 22 professional classical ballet dancers across a total of 218 ballet class or rehearsal sessions. Eleven participants completed at least 9 sessions, and were therefore included in analyses of individual relationships between s-RPE and objective measures. To calculate s-RPE, the session duration was multiplied by the rating of perceived exertion, measured using the modified Borg CR-10 scale. The Edwards summated heart rate zones (Edwards TRIMP) and Banister training impulse (Banister TRIMP) methods were used as criterion measures of internal training load. Pearson product-moment correlation coefficients were used to determine intraindividual relationships between s-RPE and objective measures. Repeated measures correlations were used to identify intraindividual relationships common across the cohort. Positive linear relationships were seen between s-RPE and objective measures across all session types (Edwards TRIMP: rrm (195) = 0.81, p < 0.001; Banister TRIMP: rrm (195) = 0.79, p < 0.001), in ballet class (Edwards TRIMP: rrm (58) = 0.64, p < 0.001; Banister TRIMP: rrm (58) = 0.59, p < 0.001), and in rehearsals (Edwards TRIMP: rrm (119) = 0.82, p < 0.001; Banister TRIMP: rrm (119) = 0.80, p < 0.001), as well as across both males (Edwards TRIMP: rrm (136) = 0.82, p < 0.001; Banister TRIMP: rrm (136) = 0.80, p < 0.001) and females (Edwards TRIMP: rrm (57) = 0.80, p < 0.001; Banister TRIMP: rrm (57) = 0.78, p < 0.001). Intra-individual correlation coefficients ranged from 0.46 – 0.96 (Edwards TRIMP: mean r = 0.81 ± 0.11, p = 0.051 – < 0.001; Banister TRIMP: mean r = 0.78 ± 0.14, p = 0.13 – < 0.001). These results demonstrate that s-RPE is a valid and practical method for measuring internal training load in professional classical ballet dancers

Epidemiology and Management of Ankle Sprain Injuries over Seven Seasons in an elite professional ballet company

Objectives: To investigate the epidemiology and management of ankle ligament sprains over seven seasons in a professional ballet company. Design: Descriptive Epidemiology Study Methods: Medical attention injury, time-loss injury, and exposure data pertaining to 140 professional ballet dancers were prospectively recorded by Chartered Physiotherapists over seven seasons (2015/16–2021/22); a period including the COVID-19 global pandemic. Results: Sixty-nine ankle sprains (46 time-loss) in 45 dancers (32%) were recorded: 51 sprains were classified as grade I, 15 were classified as grade II, and three were classified as grade III; 53 sprains affected only one ligament, whilst 16 were multi-ligament sprains. For time-loss injuries, median time-loss durations varied by grading (I - 31 days, II - 54 days, and III - 147 days) and the number of ligaments affected (one - 31 days, two - 54 days, three - 134 days, four - 137 days), with time-loss ranging from 1 to 188 days. Of the 46 time-loss ankle sprains, eight were mild, nine were moderate, and 29 were severe. The incidence rate (injuries·1000 h-1) of medical attention ankle sprains was 0.073 (95% CI: 0.046 to 0.117) in male dancers and 0.101 (95% CI: 0.069 to 0.148) in female dancers, and the incidence of time-loss ankle sprains was 0.044 (95% CI: 0.024 to 0.080) in male dancers and 0.064 (95% CI: 0.040 to 0.103) in female dancers. No significant effect of sex was observed on either medical attention (p = .304) or time-loss (p = .327) ankle sprain incidence rates. Ten percent of dancers sustained multiple sprains across the seven seasons. Fifty and 39% of ankle sprains in female and male dancers, respectively, were preceded by a history of ankle sprains. Jumping and landing (30 sprains) and non-dance movements (16 sprains) were the most common inciting movements. Bone bruising and synovitis were the most common concurrent pathologies. Conclusions: Ankle sprains placed a considerable burden on the ballet company studied. These time-loss durations specified by number and grade of ligament sprain, injury history, and secondary pathologies can guide return-to-dance rehabilitation pathways

Jumping demands during classical ballet class.

Ballet class represents a considerable portion of professional ballet training, yet the external training load demands associated with class-and particularly the jumping demands-have not been investigated. The purpose of this study was to measure the jumping demands of ballet class by sex and rank. Eleven female and eight male elite professional ballet dancers participated in 109 ballet classes taught by 12 different teachers. Jump counts and jump heights were measured during each class. A Poisson generalized linear mixed effects model was used to examine the differences in jump counts between sexes and ranks. Greater jump counts were observed during class in men than in women (153, 95% confidence intervals [CI] [137, 170] vs. 119, 95% CI [109, 131], p = 0.004) and in junior ranking dancers compared with senior ranking dancers (151, 95% CI [138, 165] vs. 121, 95% CI [108, 135], p = 0.006). Female junior and senior ranking dancers jumped at rates of 9.2 ± 2.6 and 8.6 ± 4.7 jumps·min , respectively, while male junior and senior ranking dancers jumped at rates of 9.1 ± 2.6 and 8.7 ± 2.6 jumps·min , respectively. Across all classes, 73% of jumps observed were below 50% of maximum double-legged countermovement jump height. Unlike rehearsals and performances, class offers dancers an opportunity to self-regulate load, and as such, are a useful session to manage jump load, and facilitate gradual return-to-dance pathways. Communication between health care and artistic staff is essential to facilitate load management during class

The development and validation of an open-source accelerometery algorithm for measuring jump height and frequency in ballet.

The aim was to determine the validity of an open-source algorithm for measuring jump height and frequency in ballet using a wearable accelerometer. Nine professional ballet dancers completed a routine ballet class whilst wearing an accelerometer positioned at the waist. Two investigators independently conducted time-motion analysis to identify time-points at which jumps occurred. Accelerometer data were cross-referenced with time-motion data to determine classification accuracy. To determine the validity of the measurement of jump height, five participants completed nine , nine and three double from a force plate. The jump height predicted by the accelerometer algorithm was compared to the force plate jump height to determine agreement. Across 1440 jumps observed in time-motion analysis, 1371 true positives, 34 false positives and 69 false negatives were identified by the algorithm, resulting in a sensitivity of 0.98, a precision of 0.95 and a miss rate of 0.05. For all jump types, mean absolute error was 2.6 cm and the repeated measures correlation coefficient was 0.97. Bias was 1.2 cm and 95% limits of agreement were -4.9 to 7.2 cm. The algorithm may be used to manage jump load, implement periodization strategies, or plan return-to-jump pathways for rehabilitating athletes

Rehearsal and Performance Volume in Professional Ballet: A Five-Season Cohort Study.

INTRODUCTION Few studies have published data concerning the longitudinal rehearsal and performance demands experienced by professional ballet dancers. We aimed to describe the rehearsal and performance volumes undertaken across five professional ballet seasons and identify factors associated with inter-dancer and inter-production variation in dance hours. METHODS Scheduling data were collected from 123 dancers over five seasons at The Royal Ballet. Linear mixed effects models were used to evaluate differences in: 1. weekly dance hours and seasonal performance counts across sexes, company ranks, and months; and 2. factors associated with the variation in rehearsal hours required to stage different productions. RESULTS On average across the five seasons, a peak in performance volume was observed in December, whereas rehearsal hours peaked in October and November and between January and April. Differences in weekly dance hours were observed between company ranks (p < 0.001, range in means: 19.1 to 27.5 hours per week). Seasonal performance counts varied across company ranks (p < 0.001), ranging from 28 (95% CI: 22, 35) in principals to 113 (95% CI: 108, 118) in the rank of artist. Rehearsal durations were considerably greater in preparation for newly created ballets compared with existing ballets (77.8 vs. 37.5 hours). Rehearsal durations were also greater in preparation for longer ballets, with each additional minute of running time associated with a 0.43 hour increase in rehearsal duration (p < 0.001). Full-length ballets, however, were consistently the most time-efficient to stage due to their long performance runs compared with shorter ballets (16.2 vs. 7.4 performances). CONCLUSIONS Training principles such as progressive overload and periodization should be implemented in professional ballet companies to manage the high and variable rehearsal and performance loads