Objective of the study was to conduct a 3D analysis to identify the kinematic characteristics in the key phases ol two different elemenls in sports aeroDics: Free illusion lo vertical split (FIVS) and free illusion la free vertical split (FIFVS), and compare the differences wilh me emphasis on me perlormance technique. Methods and structure of the study. Fhe elements were performed Dy a female athlete - a member of the Slovak national team in sport aerobics (age - 21 years, sports experience -16 years, height -159 cm, body mass - 52 kg). Two difficulty Group D elemenls (balance and flexibility) were investigated: Free illusion to vertical split and free illusion to free vertical split. The data were recorded and collected via SIMI Motion 3D system, version 8.5, German company SIMI Reality Motion Syslems GmbH, by 8 synchronized high-speed infrared cameras. The temporal and spatial variables were recorded: Duration of the selected phases of the elements, acceleration and velocity of the leading leg, height of the center of mass. For easier analysis of the elements, we selected 2 phases for each: Phase 1 - illusion, Phase 2 - Vertical split. Results and conclusions. The indicators that appeared to be the key ones in terms of the correct performance technique were detected: Duration of the phases, angular variables, height of the center o1 mass, and acceleration and velocity of the leading leg. The results showed the major error in the second phase o1 tree illusion to free vertical split where the minimum requirement (at least 170° between the legs in the split position) was not reached and 1he female gymnast showed only 161.31° range. Additionally, a mistake in the position of the support leg, which must be perpendicular to the floor during the vertical split, was detected in both elements (FIVS = 83.04°; FIFVS = 77.68°).