Evaluation of the effectiveness of an unloading orthosis of the knee joint based on indirect indicators and surface electromyography data

Abstract

One of the urgent tasks in the process of creating biomechanical devices, namely unloading orthoses, is to determine their effectiveness. The paper presents the results of a study of muscle fatigue of the hip synergists during isotonic contractions when performing squats both with and without the use of a knee joint unloading orthosis. In addition to determining indirect indicators that determine peripheral muscle fatigue, namely the number of squats performed and the speed of their implementation, another effective method for studying the progression of muscle fatigue, the method of surface electromyography, was used in the work. The data obtained in field experiments for both indirect indicators and surface electromyography recordings were processed by calculating the root mean square value, which made it possible to evaluate the effectiveness of the knee joint unloading orthosis using a regression statistical model. The coefficient of absolute slope of the linear regression, built on the basis of experimental data, was chosen as the criterion for evaluating the effectiveness. Surface electromyography data were recorded using the iiitech electromyographic reading module and processed using the Spike Recorder software package supplied with the module. Statistical processing of research results and calculations of linear regression coefficients were carried out using the MS Excel package. The analysis of the results obtained indicates the effectiveness of the use of the orthosis involved in the experiments, the use of which makes it possible to delay the decrease in the production strength of active muscle fibers and leads to a slower onset of peripheral muscle fatigue.