Analysis of a difficulty movement of aerobic gymnasts based on biomechanics

Background: With the progress of technology, an increasing number of studies on biomechanics in sports are being conducted. Objective: Based on biomechanical methods, the characteristics of aerobic gymnasts at different skill levels performing the difficulty movement C715 were compared to provide a reference for teaching and training. Methods: Sixteen aerobic gymnasts were divided into two groups, A and B, according to their skill levels. Kinematic data and surface electromyography were collected using modern equipment, analyzed, and compared. Results: Group A spent 0.64 ± 0.03 s during the upright restoration stage, which was longer than that of group B (p < 0.05). In the pre-swing stage, the angle between the legs of group A at the moment of free leg landing was 46.52 ± 2.14°, which was significantly greater than that of group B. Muscle force was predominantly exerted on the right side, and there were obvious differences between group A and group B in the integral electromyogram (IEMG) of the right rectus abdominis, left and right gastrocnemius, and left rectus femoris (p < 0.05). During the phase when the free leg swings forward, no significant differences in kinematic characteristics were found between the two groups; however, there were significant differences in IEMG of muscle activity for the right rectus abdominis, left and right biceps femoris, right gastrocnemius, and left rectus femoris (p < 0.05). The right gastrocnemius force of group A reached 25.77 ± 3.64 μV·S, which was significantly higher. During the 360° leg-controlled rotation phase, the minimum angle of the right ankle in group A was significantly greater than group B (p < 0.05), and the muscle activity showed significant differences in IEMG of the left biceps femoris, right biceps femoris, left gastrocnemius, left rectus femoris, and right rectus femoris. In the upright stage, the knee and ankle angles of group A were larger, and there was a remarkable difference in gastrocnemius force (p < 0.05). Conclusion: There are biomechanical differences among aerobic gymnasts of varying levels when performing the difficulty movement C715.