Excessive Knee Internal Rotation during Grand Pli in Classical Ballet Female Dancers

Classical ballet dancers are exposed daily to physically demanding movements. Among these, the Grand Plie stands out for its biomechanical complexity, particularly the stress applied to the knee joint. This study investigates the knee kinematics of healthy professional classical ballet dancers performing the Grand Plie. Twenty dancers were evaluated with a motion analysis system using a marker-based protocol. Before measurements, the self-reported Global Knee Functional Assessment Scale was delivered for the knees' functional ability, and the passive range of knee motion was also assessed. The average score on the Global Knee Functional Assessment Scale was 94.65 +/- 5.92. During a complete circle of the Grand Plie movement, executed from the upright position, the average maximum internal rotation of the knee joint was 30.28 degrees +/- 6.16 degrees, with a simultaneous knee flexion of 134.98 degrees +/- 4.62 degrees. This internal rotation observed during knee flexion exceeds the typical range of motion for the joint, suggesting a potential risk for knee injuries, such as meniscal tears. The findings provide an opportunity for future kinematic analysis research, focusing on the movement of the Grand Plie and other common ballet maneuvers. These data have the potential to yield valuable information about the knee kinematics concerning meniscus damage.