Assessing the biomechanical characteristics of defensive movements in elite boxers of different competitive levels

The purpose of this study was to identify biomechanical patterns that determine the efficiency and stability of performing defensive movements in highly qualified boxers, and to establish relationships between the level of athletic training and the nature of motor strategies. The study was conducted at the National Boxing Training Centre in Xianyang, Shaanxi Province, China, from January to December 2023. 28 athletes took part in the experiment, divided into two groups according to the level of competitive experience. The methodology included the recording of spatiotemporal, kinematic, kinetic, and electromyographic parameters when slipping, ducking, and performing sidesteps under conditions that simulated real combat. The results showed that international boxers had a high amplitude and speed of movement of the centre of mass (CM) (by 12.3% and 18.6% higher), increased angular velocity in the hip joints (by 23.2°/s), and increased muscle activation of key segments of the torso and limbs (up to + 22.8%). There were more compact and reproducible patterns of muscle activity, a lower delay in peaks of effort (-22 ms), a decrease in peak moments of force in the joints (up to -16.5%), high load symmetry (89.2%) and reduced coefficients of variability, indicating the stability of the motor programme. National-level boxers have pronounced asymmetries, high inter-repetition variability, and slower reactive responses, which theoretically may increase biomechanical strain. The findings emphasise that biomechanical maturity, expressed in stable intermuscular coordination, symmetry and variability, is closely related to the competitive level. The practical significance lies in the use of these parameters for biomechanical monitoring, personalisation of the training process, and early detection of functional limitations that can affect the reliability and mechanical efficiency of the technique in combat conditions.