Are maturation, growth and lower extremity alignment associated with overuse injury in elite adolescent ballet dancers?

Objective: To identify growth, maturation and biomechanical risk factors for overuse injury in elite adolescent ballet dancers. Methods: Maturation (Tanner scale), growth (foot length change) and age at onset of menarche were recorded in elite adolescent ballet dancers. A modified knee valgus angle and lateral tilt of the pelvis were measured using 2D video during two dance movements (fondu, temps levé) to quantify lower extremity alignment. Overuse dance injuries were recorded by a physiotherapist. The injury rate ratio (RR) associated with each variable was estimated using over-dispersed Poisson regression modelling. Results: Changes in right foot length (RR=1.41, CI=0.93-2.13), right knee angles during the fondu (RR=0.68, CI=0.45-1.03) and temps levé (RR=0.72, CI=0.53-0.98), and pelvic angles during the temps levé on the left (RR=0.52, CI=0.30-0.90) and fondu on the right (RR=1.28, CI=0.91-1.80) were associated with substantial changes in injury risk. Conclusions: Rate of growth in elite adolescent ballet dancers is likely associated with an increase in risk of lower extremity overuse injury and better right lower extremity alignment is likely associated with a reduction in risk of right lower extremity overuse injury.