The use of modern electronic technologies for motor coordination tests
Nowadays the state of athletes' physical fitness is one of the main objects of studies in numerous researches [2, 6-8]. The test of physical fitness is an element of phased monitoring in the system of sports training, applied for allocation of its level. It estimates the most informative indices of body functional status at a certain training stage or in general - the model of sports abilities, providing for allocation of specific goals of athlete's training and his individual sports perspectives .
In special literature [1-3, 7], the authors share the idea that the test is to help in planning of the training process. Meanwhile, there is no unified approach to this process based on test results. The essence of testing is to find the "weak point" to identify it as a goal of training. It is to be designed so that it could display the requirements set by specifics of this kind of sports activity.  Evaluation of special physical fitness is made of single assessments of the basic physical qualities. Here the attention is mainly focused on the most acute in sport physical qualities or specific abilities. The level of athletes’ coordination abilities, that is the basis of agility, is an important predictive index of performance of motor actions, the basis of development and efficient use of technical methods in sport and their capacity for prompt, efficient and appropriate, i.e. rational, development of new motor actions and efficient solution of motor tasks in the changing environment. 
Proceeding from the synthesis of works in the field of theory of physical education and sport [1-8], coordination and coordination abilities have been the focus of expert attention in various research centers. The relevance of the study is proved by the fact that Russian and foreign authors see solutions to the problems of special training of representatives of different sports and qualifications in the advanced development of the concept of coordination and coordination abilities, which will allegedly transform available knowledge on the rules of motor activity into innovative approaches to improve athletes’ physical abilities. Coordination abilities are proved to have both diagnostic and prognostic information value, growing with athlete’s sports experience and advanced training , which is especially important for the sports where coordination abilities are dominant among the factors determining efficiency of competitive activity.
The variety and complexity of present sports coordinating actions stipulate the need to develop the criteria enabling the quantitative assessment of motor coordinating characteristics. However, the present evaluation methods of motor coordination are frequently inapplicable due to fundamental differences and specificity of such actions. Some authors mark the inability of any classification of the evaluation criteria of coordination abilities due to great variety of testing methods [4, 5, 7].
In sports practice the guidelines of assessment of motor coordination are based on the use of biomechanical approaches when recording motor parameters. These methodologies of motor coordination assessment involve the use of hardware resources (coordination meters, tremometers- coordination meters, cinematometers, dynamometers and reflexometers, stabilographers etc.). They ensure determining the most accurate quantitative and qualitative characteristics of coordination abilities. But, on the other hand, they have some disadvantages, so one can judge the display of motor coordination only indirectly due to the lack of direct detection of the coherence of athletes’ actions during a test. This impedes obtaining reliable figures due to multiple uncontrolled variables and the lack of continuous recording of test results. Thus, a completely new approach to this issue is required.
The analysis of the theoretical studies [2-5] on this issue testifies to existing contradictions between the need to insure objective tests and its impossibility. It should be noted that in the theory and practice of sports the issues related to the information value of the testing procedure and the dynamics of physical fitness are underdeveloped, which has been recognized by many researchers [1-7].
The need to find ways to improve the coordination testing methods conditioned the choice of the topic and direction of the research.
The purpose of the study was to prove and realize modern electronic technological means to improve coordination tests.
1. Define the peculiarities of testing of athletes’ coordination abilities.
2. Identify the possibility of using sensor electronic noncontact measurement to test coordination abilities.
Nowadays the most common test suggested is the one distinguished by the coordination complicacy, the so-called "synthetic" test based on the possibility of the rotations around the longitudinal body axis in a jump. It involves the combination of movements, rare in the routine training motor activity. High result in this test (maximum rotation) requires rapid and accurate combining movements of several body parts and maintaining balance while jumping and landing. The ability to perform maximum rotation is defined as the measure of accuracy of performance of a complex motor task. Some authors call this ability dynamic balance, dynamic coordination, general motor coordination. The analysis of the performance of maximum rotation during a jump indicates to the high degree of complexity of the test task, that needs all major coordination abilities to be displayed [3, 5].
However, in case of using this method there exists a certain dependence of the subjective estimation of perception of the one who makes this test, when calculating rotations, performed by an athlete, besides testing needs some time, which makes it difficult to obtain reliable results. In this direction, the combination of direct methods of registration of biomechanical characteristics reflecting consistency in movement of body parts and determining variability of these parameters is of special research interest and perspective.
Materials and methods. In the study we designed the methodology of testing coordination abilities, determined by measuring the dynamics and accuracy of landing in an athlete’s jump around his axis. The main characteristic of the designed sensor measuring system is the ability of non-contact measurement of jump dynamics, complete angle of rotation at several turns during a jump and accuracy of landing. The block diagram of sensor measuring system based on the two-axis surface pressure matrix is shown in Fig. 1.
Fig. 1. The scheme of the measuring system
Except for this matrix with a measuring disk, made in the form of sensor pad, this system includes a microcontroller (electronic unit) with power supply and computer system. The measuring disk (Fig. 2) contains the spatial scanning capacitor electrodes along the perimeter (1) and two-coordinate matrix of surface pressure detection (2), where the jumps are performed. The total diameter of the measuring disk is 120 cm and the diameter of the two-coordinate matrix – 90 cm.
Fig.2. The measuring disk with capacitive sensors
1 - volume scanning capacitive electrodes;
2 - capacitive matrix for surface pressure detection
The volume scanning capacitive electrodes operate based on the principle of capacitive tomography. Its variable constituent as an intelligence signal is determined by availability and form of objects of research - in our case athletes’ feet - placed between electrodes.
The difference of the capacitivity coefficients between the examined objects and the environment in which these objects, sufficient number of capacitive electrodes, small distance between them and the object are present, precondition the qualitative capacitive tomography [9-11].
The example of the software for calculation of form and attitude of research subjects is shown in Fig. 3.
Fig. 3. The Capacitance Tomograph software
Results and discussion. The typical tomograms obtained during the measurement are adduced in Fig. 4. Here we see the tomograms of two feet symmetrically placed on a disc (a), two asymmetrically placed feet (b) and one foot (c). The jump height is determined by the signal amplitude values: the distance from feet to electrodes increases with the height of the jump, hence the interelectrode capacitance decreases.
Fig. 4. Tomograms
a) two feet symmetrically placed on a disc;
b) two feet asymmetrically placed on a disc;
c) one foot.
Measurement speed is an important parameter in determining the jump dynamics. The speed of the designed sensor system is 100 000 measurings per second. The accuracy of capacitance tomography is not high enough: the latter is used only to determine jump dynamics and number of turns around the axis. The landing accuracy as the main parameter of coordination abilities is determined by the capacitive two-coordinate sensor matrix of surface pressure detection. Providing the "electronic footprint", such a sensor matrix ensures allocating the foot position on the measuring surface before and after a jump. 
The structure of the surface pressure sensor matrices is based on conductive threads, which form the XY matrix (Fig. 5). The columns are located in the lower electrode layer, and the lines - in the upper layer.
Fig. 5. The structure of the surface pressure sensor matrix
The material for the conductive threads must be flexible, usually it is a conductive fabric. The lower and upper electrode layers are separated by an elastic dielectric, for example, a foam layer. Overlap areas of the upper and lower conductive electrodes form a sensed capacitance, the thickness, and therefore, the capacity of which change influenced by pressure.
The integrated circuit chip is placed in the structure of the intellectual surface pressure matrix. This chip switches the matrix electrode consistently and provides the informative signals amplification (Fig. 6).
Fig. 6. The example of two feet position on the surface pressure sensor matrix
Further, these informative signals are transmitted to a computer and processed using the relative software, which ensures calculating pressure at each measuring point with the graphic result representation . The matrix contains over 65,000 measuring points. The range of pressure on the surface is 0,1-14 kg/cm2, which provides identifying the precise position of athletes’ feet (in shoes or without) in all weight categories. Measurement is carried out with a speed of 6 frames per second. The example of signals when placing two legs on the matrix of surface pressure measurement is shown in fig. 6.
Conclusions. The use of the sensor electronic system of noncontact measurement for testing coordination abilities promotes receipt of reliable data of its measurement for athletes from different sports, facilitating the integrated solution of the issues of monitoring and the conclusion on the required correction of the training program in compliance with the results received. In its turn it will promote selection of the methods of allocation and effective use of technical means and assist in solution of the problem of regulation of the training process.
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