Matthew A. Wyon

Ballet injuries: injury incidence and severity over 1 year.

STUDY DESIGN Prospective, descriptive single-cohort study. OBJECTIVE To assess the incidence and severity of injuries to a professional ballet company over 1 year. METHODS Data for an elite-level ballet company of 52 professional dancers were collected by an in-house medical team using a time-loss injury definition. RESULTS A total of 355 injuries were recorded, with an overall injury incidence of 4.4 injuries per 1000 hours (female, 4.1; male, 4.8; P>.05) and a mean of 6.8 injuries per dancer (female, 6.3; male, 7.3; P>.05). Mean injury severity was 7 days (female, 4; male, 9; P<.05). Most injuries were classified as overuse (64%; female, 68%; male, 60%; P>.05); mean severity of injury was 3 days for females and 9 days for males (P<.05). The percentage of traumatic injuries was 32% for females and 40% for males (P<.05); the corresponding severity was 6 and 10 days, respectively (P<.05). CONCLUSION The relatively high number of injuries reported and the resulting loss of dance time support the need to introduce interventions to reduce the risk of injury in professional dancers.J Orthop Sports Phys Ther 2012;42(9):781-790. Epub 19 July 2012. doi:10.2519/jospt.2012.3893.

Oxygen uptake during modern dance class, rehearsal, and performance.

&NA; Wyon, M.A., A. Grant, E. Redding, A. Head, and N.C.C. Sharp. Oxygen uptake during modern dance class, rehearsal, and performance. J. Strength Cond. Res. 18(3):646–649. 2004.—The aim of the present study was to examine whether the workload, expressed in oxygen uptake and heart rate, during dance class and rehearsal prepared the dancer for performance. Previous research on the demands of class and performance has been affected by equipment limitations and could only provide limited insight into the physiological demands placed on the dancer. The present study noted that dance performance had significantly greater mean oxygen uptake and heart rate than noted in both class and rehearsal (p < 0.05). Further analysis noted that, during class and rehearsal, heart rates were rarely within the aerobic training zone (60–90%HRmax, where HRmax is the maximum heart rate). Dance performance placed a greater demand on the aerobic and anaerobic glycolytic energy systems than seen during class and rehearsal, which placed a greater emphasis on the adenosine triphosphate‐creatine phosphate system. Practical implications suggest the need to supplement training within dance companies to overcome this deficit in training demand.

The influence of winter vitamin D supplementation on muscle function and injury occurrence in elite ballet dancers: A controlled study

OBJECTIVES Athletes who train indoors during the winter months exhibit low serum 25-hydroxyvitamin D [25(OH)D] concentrations due to a lack of sunlight exposure. This has been linked to impaired exercise performance. The purpose of this study was to assess the effects of oral vitamin D₃ supplementation on selected physical fitness and injury parameters in elite ballet dancers. DESIGN Controlled prospective study. METHODS 24 elite classical ballet dancers (intervention n=17; control n=7) participated in a controlled 4-month oral supplementation of vitamin D₃ (2000 IU per day). Isometric muscular strength and vertical jump height were measured pre and post intervention. Injury occurrence during the intervention period was also recorded by the in-house medical team. Repeated measures ANOVA and Mann-Whitney-U statistical tests were used and significance was set at p ≤ 0.05. RESULTS Significant increases were noted for the intervention group for isometric strength (18.7%, p<0.01) and vertical jump (7.1%, p<0.01). The intervention group also sustained significantly less injuries than the controls during the study period (p<0.01). CONCLUSIONS Oral supplementation of vitamin D₃ during the winter months has beneficial effects on muscular performance and injury occurrence in elite ballet dancers.

The cardiorespiratory, anthropometric, and performance characteristics of an international/national touring ballet company.

This study examined the cardiorespiratory and anthropometric indices of professional classical ballet dancers in relation to company seniority, gender, and supplemental training. Forty-nine participants from an international touring company carried out a peak VO2 test and vertical jump test. Anthropometric measurements and supplemental training activities were also recorded for each participant. Statistical analyses showed significant differences between gender and dancer seniority levels. Gender differences were seen for jump height (M = 52.7 ± 7.12 cm; = −37.6 ± 5.32 cm) and peak VO2(M = 49.32 ± 3.72 ml·kg-1·min-1;= −43.3 ± 5.16 ml·kg-1·min-1). Differences were also seen between dancer levels for peak VO2 (artist = 46.47 ± 4.67 ml·kg-1·min-1; first artist = 42.72 ± 5.81 ml·kg-1·min-1; soloist = 43.38 ± 7.14 ml·kg-1·min-1; principal = 49.04 ± 3.63 ml·kg-1·min-1) and jump height (artist = 42.0 ± 9.11 cm; first artist = 50.33 ± 11.65 cm; soloist = 45.6 ± 9.78 cm; principal = 44.67 ± 9.53 cm). Pairwise post hoc comparisons showed that corps and principals had significantly greater relative peak VO2 than first artists and soloists (p < 0.05), while soloists and first artists had significantly greater jump heights compared to principals and corps (p < 0.05). Analysis of covariance modeling indicated that the self-reported mode of supplemental training had no association with relative peak VO2 or the percentage at which ventilatory threshold occurred. The present study has provided further insight into the cardiorespiratory profiles of classical ballet dancers, where soloists have significantly greater power capacities compared to principals and corps, who in turn had significantly greater aerobic power. These data can help guide strength and conditioning intervention strategies that need to take into account the nuances of the different seniority levels within a dance company.

Scaling concept II rowing ergometer performance for differences in body mass to better reflect rowing in water

We investigated whether the concept II indoor rowing ergometer accurately reflects rowing on water. Forty‐nine junior elite male rowers from a Great Britain training camp completed a 2000 m concept II model C indoor rowing ergometer test and a water‐based 2000 m single‐scull rowing test. Rowing speed in water (3.66 m/s) was significantly slower than laboratory‐based rowing performance (4.96 m/s). The relationship between the two rowing performances was found to be R2=28.9% (r=0.538). We identified that body mass (m) made a positive contribution to concept II rowing ergometer performance (r=0.68, P<0.001) but only a small, non‐significant contribution to single‐scull water rowing performance (r=0.039, P=0.79). The contribution that m made to single‐scull rowing in addition to ergometer rowing speed (using allometric modeling) was found to be negative (P<0.001), confirming that m has a significant drag effect on water rowing speed. The optimal allometric model to predict single‐scull rowing speed was the ratio (ergometer speed ×m−0.23)1.87 that increased R2 from 28.2% to 59.2%. Simply by dividing the concept II rowing ergometer speed by body mass (m0.23), the resulting “power‐to‐weight” ratio (ergometer speed ×m−0.23) improves the ability of the concept II rowing performance to reflect rowing on water.

Pathoanatomy of posterior ankle impingement in ballet dancers.

Dance is a high performance athletic activity that leads to great numbers of injuries, particularly in the ankle region. One reason for this is the extreme range of ankle motion required of dancers, especially females in classical ballet where the en pointe and demi‐pointe positions are common. These positions of maximal plantar flexion produce excessive force on the posterior ankle and may result in impingement, pain, and disability. Os trigonum and protruding lateral talar process are two common and well‐documented morphological variations associated with posterior ankle impingement in ballet dancers. Other less well‐known conditions, of both bony and soft tissue origins, can also elicit symptoms. This article reviews the anatomical causes of posterior ankle impingement that commonly affect ballet dancers with a view to equipping healthcare professionals for improved effectiveness in diagnosing and treating this pathology in a unique type of athlete. Clin. Anat. 23:613–621, 2010.

Fitness in contemporary dance: a systematic review.

It has been suggested that dancers are less fit compared to other athletes. However, the majority of studies make their arguments based on data deriving mainly from ballet. Therefore, the aim of the current review was to investigate: a) aerobic and anaerobic fitness, muscular strength and body composition characteristics in contemporary dancers of different levels, and b) whether supplementary exercise interventions, in addition to normal dance training, further improves contemporary dance performance. Three databases (Medline, Cochrane and the Cumulative Index to Nursing & Allied Health research database) were searched to identify publications regarding the main fitness components of contemporary professional and student dancers. At a professional level, it appears that contemporary dancers demonstrate higher maximal oxygen uptake and higher scores in muscular endurance than ballet dancers. However, contemporary dance students are equally fit compared to their ballet counterparts and their body composition is also very similar. Only two studies have investigated the effects of supplementary exercise training on aspects of dance performance. Further research is needed in order to confirm preliminary data, which suggest that the implementation of additional fitness training is beneficial for contemporary dance students to achieve a better performance outcome.

Vitamin D status in professional ballet dancers: Winter vs. summer

OBJECTIVE Serum 25-hydroxyvitamin D is produced by the exposure of the skin to sunlight. Therefore athletes who train indoors, such as dancers, are vulnerable to vitamin D deficiency. The purpose of the study was to evaluate the serum 25-hydroxyvitamin D status in UK professional dancers during periods of reduced and increased sunlight exposure (i.e., winter vs. summer), and to assess the impact on bone metabolism and risk of injury. DESIGN Cohort study. METHODS 19 elite classical ballet dancers (age 26±8.86yr; height 1.66±8.84m; mass 54.3±10.47kg) were monitored over a 6 month period for 25-hydroxyvitamin D, PTH and blood serum bone turnover markers (CTX and PINP) along with injury data. Repeated measure ANOVA and Wilcoxon and Chi-square analyses were used and significance was set at p≤0.05. RESULTS Significant changes were noted between the winter and summer test dates for 25-hydroxyvitamin D (14.9ng/ml vs. 23.9ng/ml; p<0.001), PTH (38.7pg/ml vs. 26.3pg/ml; p<0.001) and PINP (89.9ng/ml vs. 67.6ng/ml; p<0.01). The oral contraceptive had a significant effect on serum 25-hydroxyvitamin D, PTH and CTX. Soft tissue injuries were significantly lower in summer compared to winter period (winter=24, summer=13; p<0.05). CONCLUSIONS Professional ballerinas characterized by a high incidence of low serum 25-hydroxyvitamin D levels which improve marginally in the summer. These dancers also demonstrate a higher injury incidence in the winter. Oral contraception seems to increase serum 25-hydroxyvitamin D levels and has a positive effect on bone metabolism.

The Effect of a Comprehensive Injury Audit Program on Injury Incidence in Ballet: A 3-Year Prospective Study.

Objective:The aim of this study was to determine whether an intervention with individualized conditioning program based on injury history and functional movement screening would be effective in reducing ballet injury incidence. Design:Prospective 3-year epidemiological study. Setting:Professional ballet company and its in-house medical facility. Participants:Dancers from a professional ballet company over the 3-year study period. Participant numbers ranged from 52 to 58 (year 1: 52; year 2: 58; year 3: 53). Interventions:The intervention consisted of individual conditioning programs developed using injury history and functional movement screening. Analysis was undertaken of the all dancers who were present in the company during the study period. The significance of change in injuries over a 3-year period was determined using a Poisson distribution model. Main Outcomes Measures:To determine whether individual conditioning programs resulted in a decrease in injury incidence over the study period. Results:The injury count reduced significantly in years 2 and 3 (P < 0.001). Injury incidence for male dancers declined from year 1 (in year/1000 h) (4.76/1000 h) to year 2 (2.40/1000 h) and year 3 (2.22/1000 h). For women, a reduction in the injury incidence was observed from year 1 (4.14/1000 h) to year 2 (1.71/1000 h) and year 3 (1.81/1000 h). Conclusions:Through prospective injury surveillance, we were able to demonstrate the benefit of individualized conditioning programs based on injury history and functional movement screening in reducing injuries in ballet. Clinical Relevance:The implementation of well-structured injury surveillance programs can impact on injury incidence through its influence on intervention programs.

Whole-body vibration training increases vertical jump height in a dance population.

Wyon, M, Guinan, D, and Hawkey, A. Whole-body vibration training increases vertical jump height in a dance population. J Strength Cond Res 24(3): 866-870, 2010-Whole-body vibration (WBV) training has gained popularity with the strength and conditioning environment. Previous research reported improvements in strength and power after WBV interventions in untrained individuals with little hypertrophical development of the muscles, suggesting that the improvements are because of neuromuscular adaptations. The present intervention study recruited moderately trained individuals that have jumping as integral to their training. Participants were randomly allocated to an intervention or control group. The intervention group was exposed to WBV at 35 Hz for 5 minutes twice a week, whereas the control group was exposed to a similar isometric contraction stress. Results indicated that after a 6-week intervention, vertical jump height increased significantly (p < 0.05) in the intervention group than in the control group. The study concluded that WBV was able to maintain vertical jump height with very little intervention time (10 minutes a week) and therefore should be considered as an intervention form for maintaining jump performance.