Analysis of the Hip Joint Moments in Grand Rond de Jambe en l'Air

Abstract

The purpose of this study was to investigate hip net joint moments in the gesture and support legs in grand rond de jambe en l'air en dehors. Two groups of dancers, skilled (N = 8) and novice (N = 6), performed grand rond de jambe en l'air at two different vertical leg angles: 90° and 105°. Three-dimensional motion data and ground reaction force data were collected. Hip net joint moments were computed through standard inverse dynamics procedures and were normalized to each participant's mass. Normalized peak hip joint moments in both the gesture and support leg were used as the dependent variables; the independent variables were the skill level and the demand (vertical angle for the rond de jambe at 90° and 105°). A two-way mixed-design ANOVA (2 groups x 2 conditions) was used (p < .05) with the group and demand as the between and within factors, respectively. The hip joint moments of the support leg were consistently larger than the matching moments of the gesture leg. However, as the demand level increased the peak hip joint moments of the gesture leg hip showed minor changes, the support leg moments decreased. It was concluded that muscular strength is not a limiting factor for the novice dancers and that an increased demand (vertical leg angle) actually puts smaller burden on the support leg hip. Increased pelvis movement (demonstrated by the skilled dancers) facilitated the range of motion of the gesture leg without increasing joint moment cost. The hip abductor moments were identified as im-portant components in performing grand rond de jambe en l'air.