Abstract

This article provides methods for evaluating the parameters of the balance of the human body by applying accelerometry and evaluates the impact of physical load on the human body balance parameters. The work is aimed at assessing and comparing the parameters of static balance in comparatively healthy adults (20–25 year-olds) before and after physical activity. Accelerometry is one of the newest and alternative methods for research and evaluation of balance. This method is related with a posturography method; however, differently from applying the posturography method in research, no laboratory conditions and expensive equipment are needed for it. Movements of the head with respect to the trunk are recorded by means of accelerometric method even before the changes in the position of the centre of the body mass, measured by a force plate, appear. During accelerometry, the triaxial accelerometers are used that are attached to the trunk and the limbs of the subjects under study as well as computer equipment for processing of the signals measured. Speeds and accelerations of the movement of the body parts are determined by accelerators. Seeking to assess and compare the parameters of static balance in humans before and after physical load, an experimental human balance test has been conducted with the application of accelerometry. The test was conducted with 11 healthy volunteers, the main parameters of which are provided in Table 1. Prior to starting the test, blood pressure and heart rate of the volunteers was measured. During the experiment, the following main tools and supplementary equipment were used: three seismic (uniaxial) accelerometers 8344, which traced the oscillation amplitude of human centre of mass for the axes X, Y and Z. Technical characteristics of the accelerometer 8344 is as follows: sensitivity 250±20% mV/ms–2, measure range ±26 ms–2, frequency range 0.2–3000 Hz; portable computer with special software package Pulse; Electrical signal input and processing device 3660-D; veloergometer. Accelerations are registered by means of the accelerator, wherefrom by program integration twice a change in the centre of mass of a human body is received. Having a change in the centre of mass, the trajectory of the centre of mass in the horizontal plane (XY plane) may be reflected for the axes X, Y and Z. After performance of experimental research of human balance with the application of accelerometry methods, it has been established that: a) comparing the amplitude of oscillations forward/backwards with eyes opened before and after physical load, it has been noticed that the amplitude of oscillations after physical load with eyes opened increased by 22.48 percent. With eyes closed, the average of amplitude of oscillation forward/backwards before physical load is 0.0120 m, and after physical load 0.0141 m. Comparing the amplitude of oscillations forward/backwards with eyes closed before and after physical load, it may be noticed that the amplitude of oscillations after physical load with eyes opened increased by 14.99 percent. b) comparing the amplitudes of oscillations forward/ backwards and sideways experimentally received from accelerometers it is possible to state that central vision enables to identify the surrounding objects, parts of the body and their parameters. Peripheral vision has a greater impact on oscillation forward/backwards than on left/right. Meanwhile, central vision participates in oscillation control of both motion modes. Verf.-Referat