Posturography measures in specific ballet stance position discriminate ballet dancers with different occurrences of musculoskeletal injuries.

BACKGROUND: This study aimed to identify the postural sway variables that can distinguish between ballet dancers with high and low occurrences of musculoskeletal injuries. METHODS: Fourteen professional ballet dancers were assigned to a high-occurrence group (N = 5, reports >2 injuries in the previous 6-months) or a low-occurrence group (N = 9, reports ≤1 injury). Center-of-pressure (COP) data were acquired using a force platform during the following tasks: single-leg stance with eyes open, single-leg stance with eyes closed, and demi-pointe stance with eyes open. The COP standard deviation (SD) and range (RA) in both the medial-lateral (ML) and anterior-posterior (AP) directions were estimated. Between-group comparisons were made through Welch's t-tests for unequal sample size along the effect size measure (Cohen's d). Spearman's rho was used to estimate the association between the number of injuries and the COP variables. The statistical threshold was set at 1%. RESULTS: A between-group effect was found only for the demi-pointe stance, with large effects for SDML (P = 0.006, d = 1.7), RAAP (P = 0.006, d = 1.7), and RAML (P = 0.005, d = 1.7). An inverse relationship was found between the number of injuries and the demi-pointe's COP range in both directions (Spearman's rho from -0.681 to -0.726, P = 0.007). CONCLUSIONS: COP measures taken in ballet-specific positions can distinguish between dancers with a high and low occurrence of musculoskeletal injuries. Suggestions are made to include ballet-specific tasks in the functional assessments of professional dancers.

Characteristics and prevalence of musculoskeletal injury in professional and non-professional ballet dancers

BACKGROUND: Ballet is a high-performance activity that requires an advanced level of technical skills. Ballet places great stress on tendons, muscles, bones, and joints and may act directly as a trigger of injury by overuse. OBJECTIVES: 1) to describe the main types of injuries and affected areas related to classical ballet and 2) to compare the frequency of musculoskeletal injuries among professional and non-professional ballet dancers, considering possible gender differences among the professional dancers. METHOD: A total of 110 questionnaires were answered by professional and non-professional dancers. The questionnaire contained items related to the presence of injury, the regions involved, and the mechanism of the injury. RESULTS: We observed a high frequency of musculoskeletal injuries, with ankle sprains accounting for 69.8% of injuries in professional dancers and 42.1% in non-professional dancers. Pirouettes were the most frequent mechanism of injury in professional dancers, accounting for 67.9% of injuries, whereas in the non-professional dancers, repetitive movement was the most common mechanism (28.1%). Ankle sprains occurred in 90% of the women's injuries, and muscle sprains occurred in 54.5% of the men's injuries. The most frequent injury location was the ankle joint in both sexes among the professional dancers, with 67.6% in women and 40.9% in men. CONCLUSIONS: The identification of the mechanism of injury and time of practice may contribute to better therapeutic action aimed at the proper function of the dancers' bodies and improved performance by these athletes.

Comparative study of anthropometric variables in female classical ballet dancers, volleyball players and physically active subjects / Estudo comparativo das variáveis antropométricas em bailarinas clássicas e jogadoras de voleibol

O objetivo do presente estudo foi comparar medidas antropométricas(massa corporal, estatura e percentual de gordura) e a amplitude de movimento (ADM) de dorsiflexão e plantiflexão entre três diferentes grupos: bailarinas clássicas (n=14), jogadoras de voleibol (n=22) e mulheres fisicamente ativas (n=13). Assumiu-se que diferentes demandas funcionais deveriam produzir alterações nas medidas antropométricas e de ADM entre os três grupos. A massa corporal e a estatura foram maiores nas atletas de voleibol (66,42 ± 5,8 kg; 174,77 ± 5,6 cm), seguidasdas mulheres fisicamente ativas (59,93 ± 10,3 kg; 164 ± 7,5 cm) e das bailarinas clássicas (49,25 ± 4,5 kg; 157,03 ± 3,6 cm), respectivamente (p<0,05). O percentual de gordura foi maior nas mulheres ativas (30,67 ± 4,6%) quando comparadas aos outros dois grupos, que foram semelhantes entre si (jogadoras de voleibol = 24,93 ± 4,1%; bailarinas = 21,94 ± 4,3%, respectivamente). Os três grupos apresentaramsemelhante ADM entre os lados direito e esquerdo e para a amplitude de movimento ativa de dorsiflexão. Entretanto, para a plantiflexão a amplitude de movimento ativa foi maior nas bailarinas (~83°), seguidas das mulheres fisicamente ativas (~68°) e, por fim, pelas jogadoras de voleibol que apresentaram a menor amplitude de flexão plantar (~60°). As diferentes demandas impostas pelas três distintas atividades parecem ser responsáveis pelas mudanças em algumas variáveis antropométricas ena ADM da articulação do tornozelo.

The objective of this study was to compare anthropometric variables (bodyweight, height, and percent body fat) and plantarflexion and dorsiflexion range of motion (ROM) between three different groups of women: classical ballet dancers (n=14), volleyball players (n=22) and physically active subjects (n=13). The assumption was that different functional requirements should produce differences in the anthropometric variablesand ROM between the three groups. Body weight and height were higher in volleyball players (66.42 ± 5.8 kg; 174.77 ± 5.6 cm), followed by physically active women (59.93 ± 10.3 kg; 164 ± 7.5 cm) and ballet dancers (49.25 ± 4.5 kg; 157.03 ± 3.6 cm) (p<0.05). Percent body fat was higher in physically active women (30.67 ± 4.6%) compared to theother two groups, which showed similar percentages (volleyball players: 24.93 ± 4.1%; ballet dancers: 21.94 ± 4.3%). The three groups were similar in terms of total ankle ROM and active dorsiflexion ROM between the right and left sides. However, plantarflexion ROM was higher in ballet dancers (~83°), followed by physically active women (~68°)and volleyball players who presented the smallest ROM (~60°). The different requirements imposed by the three distinct physical activities seem to be responsible for changes in some of the anthropometric variables and ankle joint ROM.