Simulation of wrist movement during Nordic walking

Рurpose of research is to develop a method for obtaining a generalized wrist movement trajectory in Nordic walking for integration into the automatic control system of the upper limb rehabilitation stand. Methods. The article discusses and analyzes in detail the method of obtaining, subsequent processing and mathematical modeling of the generalized trajectory of wrist movement during the step cycle in Nordic walking. To do this, based on experimental data obtained from subjects with various anthropometric data based on semi-automatic video analysis and subsequent approximation of the obtained trajectories, for subsequent integration into the automatic control system of the upper limb rehabilitation stand based on the principle of continuous passive movement (CPM) in order to mobilize joints along the trajectories of natural movement. To digitize the laws of motion of the analytical description of the generalized trajectory of wrist movement, approximation by polynomials of the 5th order was applied. Results. In the article, individual wrist movement trajectories of groups of subjects with different anthropometric parameters were obtained and visualized. Based on them, a generalized trajectory of wrist movement in the process of Nordic walking was constructed, which became possible thanks to the use of semi-automatic video analysis techniques. By conducting a thorough statistical analysis of the collected data, significant biomechanical deviations that occur with incorrect and irrational stick length selection for Nordic walking were identified and quantified. During the mathematical modeling process, specific numerical coefficients for fifth-order polynomials were calculated and obtained, which were used in the approximation to describe the generalized trajectory of motion. Conclusion. The results obtained confirm the effectiveness of the semi-automatic video analysis method for modeling the trajectory of wrist movement and allow optimizing the parameters of rehabilitation stands, providing natural biomechanics of movements. The importance of correct stick length selection for Nordic walking is confirmed.