Knee Rotation in Classical Dancers during the Grand Plié

Abstract

For the past two decades, dance researchers and educators have been concerned about the use of the grand plié and its potential impact on injury incidence. The purpose of this study was to investigate external longitudinal rotation (ELR) at the knee during grand pliés performed in three classical ballet leg positions, 2nd, 3rd, and 4th, by professional female ballet dancers. Light reflective markers were placed on seven lower body segments of ten volunteer subjects. Subjects performed three trials of the grand plié and one demi-plié in each of the three leg positions while being videotaped. Marker locations were digitized. Five “instants” were identified in the plié: begin, demi-plié lowering phase, grand plié, demi-plié rising phase, and finish. The ELRs at the knee joints for each instant were analyzed using an analysis of variance (ANOVA) and custom matrix analysis. Results indicate that ELR values are highest at the bottom of the movement in all positions, and that 3rd and 4th position grand pliés present higher overall ELRs than 2nd position. Because ELR at the knee has been named as one of the more serious predisposing factors to knee injury, the results of this study indicate that further investigation about the grand plié is needed, and educators should include grand pliés in the training process with caution.