Analysis of balance and body positioning in ballerinas with different levels of skill
Ballet is an art that requires great skill and balance to achieve aesthetic performance. The aim of this study was to determine whether there were differences in the size of the base of support (BoS) and skill (using two previously identified indicators of aesthetic performance: back arch angle and leg separation angle) between two groups of ballerinas with different skill levels. Twenty one professional female ballerinas classed as Corps de Ballet dancers (≤ 2 years academy dancing experience; n=14) and Soloists (>2 years academy dancing experience; n=7) participated in this cross-sectional, descriptive study. All ballerinas performed three unassisted, standard ballet positions en pointe (retiré, arabesque and penché), each held for at least three seconds. Retro-reflective markers were attached to specific anatomical landmarks and tracked by a 12 camera system. The size of the BoS was calculated using a pressure platform. The BoS was significantly smaller for the Soloists than the Corps de Ballet dancers during arabesque (p=0.0239) and penché (p=0.0337) but not retiré (p=0.1131). A statistically significant, inverse correlation was found between BoS and age for all three positions: arabesque (r=-0.4948, p=0.0368) and penché (r=-0.6232, p=0.0099) and retiré (r=-0.5623, p=0.0151). There was no kinematic difference (back arch angle and leg separation angle) between the groups. Our study provides insight into the biomechanics of balance in retiré, arabesque and penché. A link exists between age, skill required for the task and size of the BoS. More experienced dancers may utilise strategies other than a large BoS to maintain balance.
Keywords: Ballet, dancer, base of support, centre of mass, balance, 3D analysis