PREDICTORS OF BOULDER CLIMBING PERFORMANCE IN YOUTH BOULDER CLIMBERS

The purpose of this study was to determine if a simple measurement using hand dynamometer could be used as predictors of boulder climbing performance in youth climbers. The study cohort consisted of 12 competitive climbers (8 males, 4 females) who competed at European Bouldering Youth Championships (B) in Slany, Czech Republic in the year 2017. The hand grip force was measured at fingertips-thumbtip grip at three wrist positions and during free holding. The effect of hand dominance in grip strength was not observed except for free holding. It could be concluded that the elite young climbers has balanced grip strength between the left and the right hand. The performance in competitions was assed by total number of number of achieved tops. The best predictor of number of top holds achieved in qualification round was the strength at free grip as it describes also upper body fitness level

COMPARATIVE MEASUREMENTS OF HEAD ANGULAR MOVEMENTS USING A CAMERA SYSTEM AND A GYROSCOPE SYSTEM

Assessments of body-segment angular movements are very important in the rehabilitation process. Head angular movements are measured and analyzed for use in studies of stability and posture. However, there is no methodology for assessing angular movements of the head, and it has not been verified whether data measured by fundamentally different MoCap systems will lead to the same results. In this study, we used a camera system and a 3DOF orientation tracker placed on the subject’s head, and measured inclination (roll) and flexion (pitch) during quiet stance. The total length and the mean velocity of the traces of the pitch versus roll plots were used to measure and analyze head orientation. Using these methods, we are able to model the distribution of the measured 2D data, and to evaluate stability and posture. The results show that the total lengths and the mean velocities related to the 3DOF orientation tracker do not differ significantly from the total lengths and the mean velocities of traces related to the IR medical camera. We also found that the systems are not interchangeable, and that the same type of system must be used each time. The designed methods can be used for studies not only of head movements but also of movements of other segments of the human body, and can be used to compare other types of MoCap systems, depending on the requirements for a specific rehabilitation examination

DETERMINATION OF HUMAN GAIT PHASE BY ZERO‐MOMENT POINT

This paper discuss approach to gait phase determination via fuzzy inference. The stability criteria applied to biped robots, namely Zero Moment Point (ZMP) have been employed. Designed fuzzy inference system uses data about the ZMP position. Gait phase is the output of our fuzzy system. Simplified human body model is introduced for computation of ZMP. Both inter- and intra-subject phase identification are examined. The developed fuzzy-rules based system is exemplified to show capability of different subjects gait data generalization. Results of designed fuzzy IF-THEN rules based system show that the proposed method is suitable for this type of task. We designed system to identify gait phases, which could potentially help to assess the quality of walking. Although the method for studying ZMP in combination with fuzzy logic could contribute to the design of new prosthesis and the diagnosis of disorders, this issue has not been systematically studied in the past

ASSESSMENT OF POSTURAL INSTABILITY IN PATIENTS WITH A NEUROLOGICAL DISORDER USING A TRI-AXIAL ACCELEROMETER

Current techniques for quantifying human postural stability during quiet standing have several limitations. The main problem is that only two movement variables are evaluated, though a better description of complex three-dimensional (3-D) movements can be provided with the use of three variables. A single tri-axial accelerometer placed on the trunk was used to measure 3-D data.We are able to evaluate 3-D movements using a method based on the volume of confidence ellipsoid (VE) of the set of points obtained by plotting three accelerations against each other. Our method was used to identify and evaluate pathological balance control. In this study, measurements were made of patients with progressive cerebellar ataxia, and also control measurements of healthy subjects, and a statistical analysis was performed. The results show that the VEs of the neurological disorder patients are significantly larger than the VEs of the healthy subjects. It can be seen that the quantitative method based on VE is very sensitive for identifying changes in stability, and that it is able to distinguish between neurological disorder patients and healthy subjects

METHODS EVALUATING UPPER ARM AND FOREARM MOVEMENT DURING A QUIET STANCE

The article focuses on designing methods for quantitative assessment of the postural stability in a quiet stance by measuring segments of the appendicular skeleton, namely upper and forearms by inertial measurement units (IMU). Although an array of quantitative analysis methods assessing data of postural stability in the quiet stance exist by measuring the head and trunk movement, these methods have not been used to date to assess the behaviour of appendicular skeleton segments, namely the upper limbs. The applicability of methods assessing arm movement during the quiet stance has been verified by comparing the values of healthy subjects performing various stance tasks. The tests determined the quantitative evaluation of acceleration measured on individual anatomical axes. The quantities included: the volume of a convex polyhedron (PV), the volume of confidence ellipsoid (EV) and average velocity (AV) obtained by plotting three accelerations against each other. The most important findings in this study concern significant differences of PV and AV between dominant and non-dominant upper extremities and significant differences of EV, PV and AV between the data measured with a subject's eyes closed and open. Higher values of indicators were in the non-dominant extremities when subjects were measured with closed eyes. Interestingly, statistically significant differences between dominant and non-dominant arm movements were documented in PV and AV cases. This is due to the PV calculation being more sensitive to random deviations, i.e. the range of measured data, since the polyhedron bounds all the measured data, as opposed to the method, where the ellipse bounds only 95% of the measured data. In the case of the AV method, it is due to higher sensitivity to movements corresponding with arm tremors; the AV calculation relates not only to the range of measured data but, above all, to the intensity of data changes in the segment measured in a particular space and time interval. These conclusions demonstrate that it is possible to apply the proposed methods in the assessment of arm movement during a quiet stance since the differences between individual stance tasks and the dominant and non-dominant arms in specific cases of quiet stance have been identified. These conclusions also indicate a potentially more extensive medical application of the proposed quantitative data evaluation obtained from IMU, for example, within the rehabilitation process of injured appendicular skeleton segments. The use of cheaper IMU methods in mobile phones or watches can be of significant benefit in measuring the segmental movement of the appendicular skeleton in quiet stance.  The methods outlined in this paper have remarkable potential in the field of telemedicine

METHODS FOR KINEMATIC ANALYSIS OF HUMAN MOVEMENT IN MILITARY APPLICATIONS: A REVIEW OF CURRENT AND PROSPECTIVE METHODS

Expansion of methods employed in the kinematic analysis of human movement for diagnosing of the physical and mental health of subjects can be traced back to the 1990`s when new information technologies and electronic recording systems started their development boom. Evaluation methods of body movement for the diagnostics of physical and mental health expanded significantly in clinical practice. This study presents an overview of these methods with the focus on how applicable the analysis of human movement can be in military practice, where they are currently marginally used. The aim of this study is to offer some recommendations on how particular methods could be utilized in an army context. This article also suggests the most appropriate methods of quantitative evaluation for posture and motion control in the course of standing, gait and other activities carried out in military training and active duty

Characterization of Human Gait using Fuzzy Logic

In medical practice, there is no appropriate widely-used application of a system based on fuzzy logic for identifying the lower limb movement type or type of walking. The object of our study was to determine characteristics of the cyclogram to identify the gait behavior by using a fuzzy logic system. The set of data for setting and testing the fuzzy logic system was measured on 10 volunteers recruited from healthy students of the Czech Technical University in Prague. The human walking speed was defined by the treadmill speed, and the inclination angle of the surface was defined by the treadmill and terrain slope. The input to the fuzzy expert system is based on the following variables: the area and the inclination angle of the cyclogram. The output variables from the fuzzy expert system are: the inclination angle of the surface, and the walking speed. We also tested the method with input based on the angle of inclination of the surface and the walking speed, and with the output based on the area and the inclination angle of the cyclogram. We found that identifying the type of terrain and walking speed on the basis of an evaluation of the cyclogram could be sufficiently accurate and suitable if we need to know the approximate type of walking and the approximate inclination angle of the surface. According to the method described here, the cyclograms could provide information about human walking, and we can infer the walking speed and the angle of inclination of the terrain

High-Contrast Stimulation Potentiates the Neurotrophic Properties of Müller Cells and Suppresses Their Pro-Inflammatory Phenotype

High-contrast visual stimulation promotes retinal regeneration and visual function, but the underlying mechanism is not fully understood. Here, we hypothesized that Müller cells (MCs), which express neurotrophins such as brain-derived neurotrophic factor (BDNF), could be key players in this retinal plasticity process. This hypothesis was tested by conducting in vivo and in vitro high-contrast stimulation of adult mice and MCs. Following stimulation, we examined the expression of BDNF and its inducible factor, VGF, in the retina and MCs. We also investigated the alterations in the expression of VGF, nuclear factor kappa B (NF-κB) and pro-inflammatory mediators in MCs, as well as their capacity to proliferate and develop a neurogenic or reactive gliosis phenotype after high-contrast stimulation and treatment with BDNF. Our results showed that high-contrast stimulation upregulated BDNF levels in MCs in vivo and in vitro. The additional BDNF treatment significantly augmented VGF production in MCs and their neuroprotective features, as evidenced by increased MC proliferation, neurodifferentiation, and decreased expression of the pro-inflammatory factors and the reactive gliosis marker GFAP. These results demonstrate that high-contrast stimulation activates the neurotrophic and neuroprotective properties of MCs, suggesting their possible direct involvement in retinal neuronal survival and improved functional outcomes in response to visual stimulation