Lower Extremity Horizontal Work,but Not Vertical Power,Predicts Balance Performance in Female Collegiate Dancers

Abstract

Dancers, similar to other athletes, often perform vertical and horizontal jumps. Lower extremity (LE) work, power, and balance are important in performing these movements. However, whether these qualities are inter-related in dancers remains unclear. Our purposes were to examine if 1. LE horizontal work, vertical power, and balance were inter-related, and 2. LE horizontal work and vertical power would predict balance in female collegiate dancers. Sixty-one collegiate female dancers (18.3 ± 0.7 years; 164.7 ± 7.3 cm; 61.7 ± 9.5 kg) performed Single Leg Hops (SLH, m), and Vertical Jumps (VJ, cm). The resulting distances were used to calculate horizontal work (hWork, joules = weight[N] * SLH), and vertical power (vPower, watts = 78.5 * VJ + 60.6 * mass[kg] - 15.3 * height [cm] - 1,308). Balance was operationally defined as the bilateral composite Star Excursion Balance Test (SEBTcom, % leg-length-LL) reach scores in the anterior, posterolateral, and posteromedial directions. Pearson correlation coefficients examined relationships among hWork, vPower, and SEBTcom. A stepwise linear regression examined whether hWork and vPower predicted balance (p < 0.05). SEBTcom (75.7 ± 6.2% LL) showed moderate correlations to hWork (800.3 ±191 joules; r = 0.59, p < 0.001), and fair correlations to vPower (3289.1 ± 1047.7 watts; r = 0.31, p = 0.02). hWork showed moderate-strong correlations to vPower (r = 0.70, p < 0.001). hWork predicted 32.4% of the balance score variance (p < 0.001), but vPower did not enter the regression model. Overall, LE horizontal work, vertical power, and balance were positively correlated in female collegiate dancers. LE horizontal but not vertical power predicted almost one-third of the changes in balance. The similar horizontal directional task demands in both the SEBT and SLH versus the differing horizontal and vertical directional task demands in the SEBT and the VJ, respectively, may partially explain these findings. As LE work, power, and balance are interrelated, whether dancers’ participation in training programs can improve their jumping, landing, and balance performance needs further examination.