Isokinetic trunk muscle performance characteristics of classical ballet dancers

Recent availability of trunk isokinetic dynamometers has created a need for documented normative data. The purpose of this initial investigation was to determine isokinetic norms for trunk flexion and extension in classical ballet dancers. Strength levels were determined by peak torque. A fatigue index was derived from 20 reciprocal contractions. Twenty-three dancers were tested-17 females (F) and six males (M). Female dancers were further divided into professional (FP) and semi-professional (FSP) groups. A questionnaire regarding dance background, training habits, and back pain was administered. Means and ranges for peak torque and fatigue were calculated for each group. T-tests were performed on peak torque and fatigue data grouped by gender and dance status. Peak torque analysis indicated trends of M > F and FP > FSP. A statistically significant (p < 0.05) difference existed for trunk extension between FP and FSP dancers, a possible sport-specific adaptation. Fatigue levels were lower than expected, and possible explanations are considered.