title: Lumbo-pelvic stability and electromyography of abdominal muscles in ballet dancers.
abstract: Evaluating the ability to rectify and maintain lumbar adjustment can contribute toward the understanding of the behavior of abdominal muscles and their participation in the stability of pelvic muscles in dancers during the posterior pelvic tilt and double straight leg lowering tests. Nine healthy volunteers (male and female ballet dancers; age mean: 25.9 +/- 7.37 years) underwent maximal isometric voluntary contraction (MIVC), isometric voluntary contraction at 50% of MIVC, posterior pelvic tilt (PPT) and double straight leg lowering (DSLL) tests. The tests were carried out in a single day, with 3 repetitions each. During the tests, electromygraphic signals of the rectus abdominis, obliquus internus and obliquus externus were recorded. The signal acquisition system was made up of bipolar surface electrodes, electrogoniometer and an electromechanic device (pressure sensor), which were connected to a signal conditioner module. Root mean square values of each muscle during the DSLL and PPT were converted into percentage of activation of 50% MIVC. Lower back pressure was submitted to the same process. ANOVA with repeated measures was performed, with the level of significance set at p < 0.05. The results revealed that all dancers were able to maintain posterior pelvic tilt and there was trend toward greater activation of the bilateral obliquus internus muscle. In an attempt to keep the pelvic region stabilized during DSLL, there was a greater contribution from the obliquus externus muscle in relation to other abdominal muscles.
authors.affiliation: Department of Physiotherapy of the Science and Technology College - São Paulo State University, Brazil. rubnegrao@yahoo.com.br
authors.forename: R de Faria
authors.initials: Rde F
authors.lastname: Negrão Filho
authors.forename: L Alves
authors.initials: LA
authors.lastname: Silva
authors.forename: T Lombardi
authors.initials: TL
authors.lastname: Monteiro
authors.forename: N
authors.initials: N
authors.lastname: Alves
authors.forename: A Cesinando
authors.initials: AC
authors.lastname: de Carvalho
authors.forename: F Mícolis
authors.initials: FM
authors.lastname: de Azevedo
mesh_terms: D000009:Abdominal Muscles / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D003615:Dancing / Q000502:physiology*; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007866:Leg; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D010388:Pelvis; D004856:Postural Balance / Q000502:physiology*; D055815:Young Adult