title: Kinematic evaluation of the classical ballet step "plié".
abstract: Lack of alignment between the lowerlimb structures, such as the hips, knees, and longitudinal arches of the feet, has been described as an important predisposing factor in musculoskeletal injury among classical ballet dancers. However, no studies were found that analyzed basic ballet movements with quantification of objective criteria of the movements. The purposes of this study were: 1. to establish a methodology to quantify, using kinematic evaluation, the technical criteria that guide the correct execution of all phases of the plié (simultaneous flexion of the hips, knees, and ankle joints); and 2. to explore whether experienced ballet dancers respect those criteria when performing the plié. The technical criteria considered were the following: 1. midfoot stability; 2. pelvic positioning in a neutral alignment; 3. pelvic stability, represented by pelvic angle variation; and 4. vertical alignment of the knee joint with the second toe of the ipsilateral foot. Twenty dancers from Porto Alegre, Brazil, with 18 years of uninterrupted ballet training, were filmed while performing plié using four synchronized cameras. The descriptive statistical analysis involved calculating the median, minimum, and maximum of each of the technical criteria. Results showed that for criterion 1, the 20 dancers showed great stabilization of the midfoot; for criteria 2 and 3, 18 dancers displayed pelvic instability tending toward retroversion throughout execution of the plié; and for criterion 4, 13 dancers presented with medial misalignment of the knees at all phases of the plié. Using these criteria, it was possible to characterize the plié from a kinematic point of view.
authors.affiliation: Federal University of Rio Grande do Sul, Brazil.
authors.forename: Kaanda Nabilla Souza
authors.initials: KN
authors.lastname: Gontijo
authors.affiliation: Federal University of Rio Grande do Sul, Brazil.
authors.forename: Cláudia Tarragô
authors.initials: CT
authors.lastname: Candotti
authors.affiliation: Federal University of Rio Grande do Sul, Brazil.
authors.forename: Grace Dos Santos
authors.initials: Gdos S
authors.lastname: Feijó
authors.affiliation: Federal University of Rio Grande do Sul, Brazil.
authors.forename: Lais Paixão
authors.initials: LP
authors.lastname: Ribeiro
authors.affiliation: Federal University of Rio Grande do Sul, Felizardo 750, LAPEX Building/Room 222, 90690-200 Porto Alegre - Rio Grande do Sul - Brazil. jefferson.loss@ufrgs.br.
authors.forename: Jefferson Fagundes
authors.initials: JF
authors.lastname: Loss
mesh_terms: D000843:Ankle Joint / Q000502:physiology; D001938:Brazil; D003615:Dancing / Q000502:physiology*; D005260:Female; D005545:Forefoot, Human / Q000502:physiology; D006365:Heel / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D004856:Postural Balance / Q000502:physiology*; D014034:Toes / Q000502:physiology*