Changes in the Indicators of Postural Stability of the Body of Athletes Specializing in Ballroom Dancing under the Influence of Training Loads and Competitive Activity

The purpose of the study is to establish changes in the indicators of postural stability of the body of ballroom dancers under the influence of training loads and competitive activity. Materials and methods. With the help of a force plate with biological feedback “Stabilan 01-2” the interaction of athletes with the support was registered, in particular the movement of the common center of pressure of the feet on the support. The standard (with open eyes) and complicated (with closed eyes) Romberg tests were used. The indicators were being recorded for 30 seconds at rest, as well as under the conditions of visual control before and after a typical training session, before and after competitions. The obtained data in two experimental situations were compared with initial data at rest. In total, 25 couples were studied. Couples aged 18-19 years old were studied in the amount of 15 couples, training at the stage of maximum realization of individual capabilities, and 10 couples at the age of 14-15 years old, training at the stage of specialized basic training. All the participants actively train and regularly participate in competitions. Results and discussion. Studies have shown that in the tests, which were carried out, there were obvious differences in posture stability associated with the influence of training and loads used in them. The analysis of the data proved that the test results indicate the regular differences in the indicators of posture stability in accordance with the sports experience of athletes after a training session in comparison with the initial ones (in the so-called state of rest). Athletes aged 18-19 years have a significantly higher quality indicator of balance function than people aged 14-15 years (p <0.01), which in our opinion is explained by dancing experience and adaptive changes that occur in the athlete’s body, because, according to researchers, the higher the specified indicator is, the correspondingly higher the human statokinetic stability is. A separate analysis of female and male representatives indicated less frontal scattering in male athletes aged 18-19 years old compared to girls of this age group (p <0.05). The area of the ellipse when conducting the test with closed eyes also significantly differed in boys from girls, regardless of dancing experience (p <0.05). Comparing the stability indicators of girls in dancing shoes and without them, we stated a regularity of a decrease in the quality of body balance from “more to less”: from maintaining a classical posture with open eyes to the same posture in dancing shoes in a test with closed eyes. The results of the correlation analysis between the indicators of static-dynamic body stability and the sports result of more experienced girl-partners allowed to establish the existence of a connection (r=0.61), which reflects the tendency according to which, with an increase in sports performance, the indicators of the oscillation amplitude of the center of body pressure on the support, its linear velocity of movement, the length of this trajectory both in the sagittal and in the frontal planes, the area of the ellipse decrease, which complements and confirms the data of other authors [6, 10]. Conclusion. Thus, according to the results of the study, it was found that the visual analyzer plays an important role in maintaining balance, which can be seen in the test results of both age groups. Moreover, the greater influence of visual control on the postural stability was stated in girl-partners than in boy-partners. It was also found that the quality of the balance function before and after competitions in older dancers did not change, while in less experienced dancers it decreased by almost 2%, and a comparison of the changes that occurred under the influence of training loads and competitive activity made it possible to establish the presence of adaptation to competitive loads, which manifested in a very significant improvement in the work of systems of vertical posture support in all age groups

Application of Multi Body System Coupling Dynamic Model in Posture Stability Evaluation of Sports

Due to the lack of more precise and complete data support, the reliability of posture stability evaluation method based on common technology is poor. In the face of such problems, the application of multi-body system coupling dynamic model in the evaluation of sports posture stability is proposed. The coupling dynamic model of human motion posture is established, and the relevant data of human motion posture is collected. The complete data of human motion posture is obtained by solving the dynamic model. Choose the appropriate stability evaluation index, calculate the stability evaluation index, divide the stability level, and realize the evaluation of posture stability. The experimental results show that: the application of multi-body system coupling dynamic model in the stability evaluation method makes the time delay and data error of the evaluation method small, and its overall reliability is improved.

EFFECT OF LOWER LIMB EXERCISE ON POSTURE STABILITY AND BRAIN ACTIVITY DURING WHOLE BODY VIBRATION FOR THE ELDERLY

This study aimed to investigate the effect of lower limb exercise on electroencephalogram (EEG) activity and posture stability during whole body vibration (WBV) for healthy elderly people. Subjects were composed of 20 elderly people who were over 60 years old and had no disease. They were subjected to WBV of 30[Formula: see text]Hz and strength intensity of 20 (total 5 sets, 20[Formula: see text]s/set, rest time: 20[Formula: see text]s, except for the final set). The subjects were grouped into two groups. One group of 11 subjects was WBVSt (WBV of upright stance) and the other group of nine subjects was WBVSq (WBV of squat posture). In the WBVSt group, the subjects were requested to maintain a standing position, whereas those in the WBVSq group were asked to perform 60∘-knee flexion squat at 2[Formula: see text]s intervals during WBV stimulation. In this study, the electromyography (EMG) was measured on the right and left erector spinae, rectus femoris, vastus lateralis, vastus medialis, tibialis anterior to evaluate lower limb muscle activity and postural stability during timed up and go (TUG) test before and after WBV. The EEG was measured on frontal (F3, F4, F7, F8), central (Cz, C3, C4), temporal (T3, T4, T5, T6), parietal (P3, P4), and occipital (O1, O2) lobes to evaluate brain activity during the check of mini-mental state examination for dementia screening (MMSE-DS) before and after WBV. The results of this study showed improved postural stability and muscle activation for the healthy elderly during lower limb and WVB exercises. The WBVSq group showed higher changes in TUG-test ([Formula: see text]) and iEMG analysis by EMG ([Formula: see text]) compared with the WBVSt group. However, there was no significant change in MMSE-DS ([Formula: see text]). Because of the increase in relative SMR power by EEG, the central (C4), frontal (F7) and parietal (P3, P4) lobes were activated in WBVSt group ([Formula: see text]); however, all regions, except the parietal lobe, were activated in WBVSq group ([Formula: see text]). Lower limb exercise with WBV stimulation improved postural stability, lower limb muscle, and brain activation for the elderly. These results may be helpful to the protocol of exercise using WBV for the healthy elderly.

Compensatory image of the stability of people with multiple sclerosis and atrial vertigo based on posturography examination

Pathophysiology of balance disorders due to multiple sclerosis (MS) and atrial vertigo (AV) is different. We evaluated posture stability when maintaining balance in people with MS presenting symptoms of ataxia and those with AV. We included 45 women (15 with MS; 15 with AV; 15 controls). A posturography platform was used to measure balance parameters. To characterize the image of stability and the compensation of balance disorders, the surface area of the stabilogram (SAS), vision control index (VCI) and the vision-motion control index (VMCI) were used. The stability image of people with MS and AV with eyes open (p = 0.002), with eyes closed (p = 0.080) and with visual biofeedback (p = 0.0008) differed significantly. SAS depended on visual biofeedback regardless of the occurrence of balance disorders and was the basis for determining the compensatory share of vision-motor coordination. Differences in VCI between groups were insignificant. VMCI was significantly higher in people with balance disorders than in those without, but similar in the MS and AV groups. The image of stability is different in people with MS and AV. Thanks to visual biofeedback, it becomes possible to launch effective vision-motor coordination when compensating balance disorders. VCI may become the measure of compensation for balance disorders.

Robust posture tracking control of stable coaxial two-wheeled AGV using the approximate inverse system and LMI

This paper describes the design of the posture controller for two-wheeled AGV. The objective is to improve the posture stability when running on ramps by balancing between vehicle body attitude angle and wheel angular velocity target value. The effectiveness of the controller by simulation and experiment was confirmed.