Exploring Active and Passive Contributors to Turnout in Dancers and Non-Dancers
OBJECTIVE: Lower-extremity external rotation, or turnout, is a fundamental skill in dance. Active standing turnout has previously been measured using low-friction turnout disks. Turnout is influenced by passive range of motion (ROM) and strength, with passive ROM a function of bony morphology and ligamentous/capsular restraints. PURPOSE: Our study explored the relationship between standing active turnout and femoral bony morphology, hip passive ROM, and strength among dancers and non-dancers. METHODS: Cross-sectional cohort study. Twenty-three female dancers and 13 female non-dancers aged 18 to 30 yrs were recruited. Standing active turnout on reduced-friction disks, ultrasound images of femoral version, supine passive turnout, and hip abductor and external rotator strength were collected. RESULTS: Dancers demonstrated greater standing turnout (107º±18º) than non-dancers (92º±28º), but the difference was not statistically significant (p=0.054). A significant difference was found for femoral version (p<0.001), 4.7º (±2.8º) for dancers vs 12.1º (±4.6º) for non-dancers. Dancers demonstrated greater supine turnout, 102.7º±18.8º, compared to non-dancers, 84.3º±30.4º (p=0.031). Dancers were able to achieve greater peak force in turnout compared to non-dancers: 2.44±0.44 N/kg and 1.72±0.59 N/kg, respectively (p<0.0001). Supine total turnout was the best predictor of active turnout, contributing 48% of the variance (r=0.696, p<0.001). CONCLUSION: Our findings suggest supine turnout is the largest predictor for standing turnout. Investigating dancers and non-dancers independently, our finding were similar to previous studies suggesting the femoro-acetabular complex may be influenced by dance training, contributing to differences in bony morphology between dancers and non-dancers. Although strength did not significantly contribute to active standing turnout, dancers demonstrated greater peak force compared to non-dancers.