ABSTRACT
Objective - to study the effect of hip contractures on the strength of the thigh muscles. Gait analysis was performed in the OpenSim 4.0 program, gait2394 was taken as the basis. Created 4 models with contractures of varying severity. We analyzed the change in the work of the thigh muscles in normal conditions, with adduction, flexion-adduction and flexion-adduction contractures with shortening. According to the data obtained in modeling the adductive and flexor-adducing contractures of the hip joint, it can be noted that contracture changes the work of the muscles around the hip joint. It was noted that modeling only adduction contracture causes noticeable changes in the medial group of femoral muscles and muscle stabilizers. Of the muscles of the posterior thigh group, m.semimembranosus, m.semitendinosus and m.biceps femoris are most susceptible to changes. These muscles change the level of load, and most importantly, periods of excitation and muscle relaxation shift. Simulation of combined flexion-adduction contracture showed that muscle dysfunctions increase, and m.sartorius, an anterior thigh muscle, was added to the muscles in which noticeable changes additionally occurred. With simulated adduction and flexion adduction contractures, changes occur in all the muscles of the thigh, periods of their excitement and relaxation shift, but the level of muscle tension is close to normal values - not exceeding them by 20-30%. Flexion-leading contracture with shortening of the limb leads to a distortion of muscle parameters in the form of excessive loads for the step (up to 100-300%). Based on the obtained simulation results, the inability of the muscles to develop the necessary efforts leads to a change in the parameters of the step in the form of a decrease in the length of the step and the duration of the periods of support on the foot, a change in the nature of the transfer of the foot. It is logical to assume that a long period of impaired muscle function will lead to the development of sustainable changes in the walking pattern.
