Coordination patterns of the lower limb and pelvic complex during the demi-plié movement with different end-goals in classical ballet

Demi-plié is a coordinated ballet movement involving a continuous bend of the knee while maintaining turnout and grounded heels. Twelve classical dancers (9 females, 3 males) performed the demi-plié itself and in preparation for pirouette en dehors, relevé, sauté, and sissonne fermée de côté. Motion capture was used to acquire the two knee-angle trajectories and the hip vertical trajectory. Lissajous-type coordination plots were quantified using an inter-knee width metric, a late goal-state divergence metric, and a timing proxy based on descending-phase duration. Significant condition effects were found for width (F(4,44) = 22.73, p < 0.001), goal-state divergence (F(4,44) = 9.60, p < 0.001), and descending-phase duration (F(4,44) = 3.77, p = 0.0101). Pirouette en dehors showed the largest width (16.23 ± 8.46 deg) and goal-state divergence (15.77 ± 11.43 deg). These findings support the view that dancers learn multiple context-sensitive realizations of the demi-plié and that this basic movement expresses both intrapersonal coordination and task-specific reorganization toward the subsequent movement goal.