AUTOMATED ASSESSMENT OF A STUDENTS CIRCULATORY SYSTEM FUNCTIONAL STATE USING MARTINE ' S TEST

Background. The systematic self-control of students' health state allows optimizing the educational process organization of physical education and contribute improving the functioning of body systems. One of the common methods of such observation is the functional Martine's test, which provides an opportunity to investigate the dynamics of changes in blood pressure and heart rate between the resting state and every minute for five minutes after the load. In most cases, this load characteristic sufficiently fully reflects the student's cardiovascular system state. The determination of the characteristic patterns of such states will allow offering a mechanism for assessing the functional state of the circulatory system. The regular Martine's testing will allow observing the dynamics and evaluating changes in the body during the observation period. Objective. Creation of an automated system for assessing of a student’s circulatory system functional state changes. Methods. The students database of the National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute” created during the research by the Department of Physical Education, was used for the study. To determine the functional patterns, separately for boys and girls, cluster analysis was used by the "k-means" method in the parameter space of the blood pressure and heart rate measured during the functional Martine's test. As a result, 7 clusters of states for young men and 8 clusters for girls were obtained. Clusters differ significantly in the nature of the response of blood pressure and heart rate to the load test. The centroids of the resulting clusters were further considered as functional patterns (the most typical representatives) of the body's response to the test physical load. The assessment of the circulatory system functional state is calculated by comparing the student test data with the previously defined functional patterns by the minimum Euclidean distance criterion. Conclusions about the functional state of the system are formed. Results. The clusters of the circulatory system functional states in the extended space of blood pressure and heart rate parameters of functional Martine's test are obtained. The clusters correspond to the normal states and different stages of the regulatory reserves reduction of the body. The algorithm allowing to consider features of an organism functional state at essential deviation of Martine's test indicators from a certain functional pattern is developed. This admits controlling the individual level of physical activity, adapting the training program and identifying conditions requiring additional medical control. Conclusions. As a study result, the automated system for assessing the functional state of technical university students circulatory system using Martine's test was developed. The system relates observation to one of the study sample clusters that were obtained using the "k-means" method. For additional information on the state of the circulatory system, the average radius of the cluster is used, since objects that are far removed from the center may have properties similar to those of a neighboring cluster. The developed system provides an opportunity for screening control the students cardiovascular system state during the educational process.


Introduction
Systematic self-monitoring of your health is a necessary step for improving the functioning of body's systems and supporting it in a tone.Performing physical exercises positively affects the student's body and allows performing an analysis of physical abilities.With the help of Martine's functional test, it is possible to investigate the dynamics of changes in blood pressure and pulse between the resting state and every minute for five minutes after exercise.
Since the state of physical health can vary regardless of physical activity, the regular conduct of Martine's test [1,2] will allow observing the dynamics of changes in the body for a certain period [3][4][5].
The objective of the work is to create a system for assessing changes in the functional state of the circulatory system by comparing the test parameters with predefined functional blood circulation patterns based on the criterion of the minimum 145 145 Euclidean distance and forming of basic and additional conclusions about the state of the organism.

Materials and methods
The students database of the National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", created in the course of research conducted by the Department of Physical Education, was used for the study.
All students had a medical certificate about the ability of taking physical education courses, as well as gave written consent to the passing of the test.Testing consisted of going through Martine's test that is, performing 20 sit-ups in 30 seconds.
Immediately before the start of the test and every minute for 5 minutes afterwards, the systolic and diastolic blood pressure and heart rate (HR) values were measured.
To determine the functional patterns (centroids of clusters), a database of 1419 students single multidimensional observations was used.The gender composition of the base is 800 men and 619 women.The dimension of clustering space of the circulatory system functional state was determined dim = 18: systolic, diastolic blood pressure and heart rate for 6 points of time Martine's test.
To formulate a formal description of the characteristics of each cluster, 353 quantitative indicators were analyzed that reflect the functional state of the circulatory system and the psychophysical state of patients.
Separately for males and females, to determine the functional patterns, that is, the ratios of the above indicators, a cluster analysis using the "k-means" [6] method was performed.At the preliminary stage of the research, 7 clusters were obtained for males and 8 clusters in females data, which differed significantly from each other by the nature of the responses of blood pressure (BP) and heart rate metrics to Martine's test.The centroids of the resulting clusters were further considered as functional patterns (the most typical representatives) of the body's response to the test of physical activity.
To study changes in the state of the circulatory system, the database contained data from repeated tests of students, which were performed from 2 to 6 times at different intervals.This database contained 590 observations, consisting of 268 female and 322 male students and additional 133 indicators of the psychophysical status of students.
Euclidean distance was used as a criterion for the proximity of the individual student, named below as j x to the center i c of a particular cluster i: is a coordinate value k of cluster centroid i, and () k j x is a coordinate value k of the object j x which is the member of cluster i.In addition, for each cluster, a parameter is calculated, which we will call as it's average radius: which is a member of cluster i; i n is an object quantity of cluster with number i.

Results
The study used a database containing blood pressure and cardiovascular measurements of students who had taken Martine's test more than once.
The reciprocal arrangement of clusters' centroids, which were used as functional patterns of response to an exercise test, are presented in Figs.1-4 where SP and DP are systolic and diastolic blood pressure respectively.Here, each cluster centroid is represented by 6 centers corresponding to 6 time points of Martine's test.
To assess the circulatory system functional state the following algorithm was developed and applied.
1. Using proximity measure (1), we define the cluster with minimal distance to the analyzed object.
2. Using proximity measure (1), we define the cluster with subminimal distance to the analyzed object.
3. Determine whether the parameters of this test were located within the average radius of the cluster ("yes" or "no").
4. If test parameters were located within the cluster average radius, then only the information about functional and psychophysical features of the closest, cluster is displayed as result.
5. If "no", the information about functional and psychophysical features of the cluster with a subminimum distance is displayed in addition.
The flowchart of the above algorithm is shown in Fig. 5.

Discussion
Using the developed system, the results of the monitoring application of Martine's test were analyzed from 1 to 6 times in 590 observation students, which consisted of 268 female and 322 male students.Each observation corresponds to a certain code of the functional state (cluster number).
Causes of existing functional states of blood circulation were analyzed using 133 indicators of the psychophysical state of students.The values of these indicators in clusters were analyzed using a dispersion analysis [7].
Analysis of changes in these indicators is not the purpose of this work and deserves a separate consideration.
Distribution of students in clusters, presented in Tables 1, 2 allows estimating the prevalence of a certain regulatory type in student groups.
Thus, the developed algorithm allows taking into account additional possible features of the The algorithm allows determining blood circulation conditions, which correspond to reduction of regulatory reserves and significant increase in blood pressure.This allows controlling the individual level of physical activity, modifying the training program and identifying conditions that require additional medical control.
In addition, the use of a system for screening control of large groups of students is possible for the identification of persons at high risk of sudden circulatory disorders.
The results of the system were compared with expert assessments.A completely acceptable (87%) match of both types of estimates is established.

Conclusions
As a study result, a system for assessing the functional state of the students cardiovascular system with the use of Martine's test was developed.The system matches observation to one of the study sample clusters that were obtained using the "k-means" method.For additional information on the circulatory system state, the mean radius of the cluster is used, since objects that are far removed from the center may have properties similar to those of a neighboring cluster.
The developed system provides an opportunity to control the state of the cardiovascular system as a one-time, and to conduct screening control of a group of students.
The size of the input vector (input structure) and the number of functional patterns are not fixed and can be modified in the process of improving the system.
The future studies will focus on finding larger differences between clusters to refine their characteristics.Also, the studies will focus on finding patterns of changes in the functional status of the circulatory system of students who have passed Martine's test more than once in order to identify risk groups of sudden circulatory disorders and decrease functional reserves.Further research will be aimed at determining the optimal number of functional patterns and a more detailed assessment of changes in physiological parameters.

Table 1 .
Number of students in clusters.Males

Table 2 .
Number of students in clusters.Females