PhD K.V. Sukhinina
Postgraduate A.Y. Kolesnikova
Postgraduate O.Y. Aleksandrovich
Irkutsk State University, Irkutsk

Keywords: anthropometric measurements, fat mass, bone mass, muscle mass, cardiorespiratory system, female students, special health group.

Introduction. Nowadays both domestic and foreign scholars pay a lot of attention to research of students' health [2,9]. The given issue seems vital as young people' health has significantly declined [5]. Thus, 40-50% of senior pupils are diagnosed with chronic diseases [8] and the rate of chronic pathologies among first-year students is being constantly on the rise [9]. The number of students attributed to a special health group (SHG) goes up every year [12]. Thus, according to the reference data, 10-15% of first-year students were attributed to SHG in 2014 [9].

It was proved that university studies are associated with great mental workload that provoke tension of all adaptation mechanisms in the first-year students' bodies [10,12,13,15]. It is especially hard for SHG students to adapt to new social, mental and physical environments [3,4,11,12].

In this regard scholars eagerly inquire into a matter of physical working capacity levels (aerobic capacity, cardiovascular system indices) of students from both body conditioning and special health groups [8,11]. Cardiorespiratory system indices are widely studied as they provide vital data about oxygen supply and the level of adaptation to stress, including stress during academic studies [6,11]. In this connection, cardiorespiratory system research seems a pressing issue for predicting the adaptation processes of students with health issues.

Any changes in lifestyle (physical activity increase, day regimen and diet changes, mental workload and stress increase) were proved to influence directly the adipose tissue depot of the body [14,16]. Thus, it is of high theoretical and practical relevance to study body composition indices of students during their studies.

Objective of the research was to study peculiarities of body composition and cardiorespiratory system indices of female students from special health group in the process of exercising.

Study methods and structure. Anthropometric measurements and fitness tests of first- and second year students of Irkutsk State University were carried out twice a year in the first and the second year of studies (in September and May). Subjects did physical exercises by a customized training program.

In the given research paper the M.V. Chernorutsky's classification of somatotypes [1] was used. The subjects had their height and weight measured using standard methods [1] and body mass index (BMI) calculated [2].  BMI was evaluated in accordance with the WHO guidelines [2].

Bone, fat and muscle mass were estimated using Matiegka's [16], Pazziskova's equations (1961) in order to determine body composition indices. Subjects' somatotypes were also determined according to the Sheldon's classification [1].

In order to establish a cardiorespiratory system status blood pressure (BP) and heart rate (HR) were measured, graded exercise fitness tests and orthostatic tests were done, along with vital capacity (VC) and birth-death ratio (BDR) calculations [2]. The study results data were statistically processed on IBM/AT PC in Microsoft Office Excel 2010. M - weighted arithmetic mean, ơ - standard deviation, and m - error of mean were calculated. Statistical significance of means was verified using Student's t-test and rated by the Student's coefficient in the analysis of variance, critical test significance value p set equal to 0.05.

Study Results Discussion. 125 female students of Irkutsk State University were examined in the course of the study (mean age 17.9 ± 1.19 years) (М±σ).

The study group included 86 subjects: 39 of them were diagnosed with medium and high myopia, 20 – vasomotor dyscrasia and 27 – 1st and second degree scoliosis (by V.D. Chaklin's classification). The reference group was made of 39 students.

As for somatotypes of the study subjects, the normosthenic and asthenic types prevailed [7]. They are characterized as well proportioned, broad shouldered, with well developed bone and muscle tissues and a well developed chest. There were a few persons of the hypersthenic type. Thus, the majority of first-year female students were characterized by normal physical development.

Height and weight of the first-year students fell within the normal limits. At the same time weight and BMI of the females with musculoskeletal disorders were evidently higher than those of the subjects diagnosed with myopia (p<0.05). The mean skinfold thickness of all the subjects fell within the normal limits. We have not found any significant differences in the mean skinfold values in the study and reference groups.

The resulting data can be explained by the fact the first-year female students with muscular skeletal disorders pursue a less active lifestyle than those form the 2d (vasomotor dyscrasia) and 3d (myopia) subgroups. 

Fat mass of all first-year female students was found to exceed the normal limit while bone and muscle mass fell within the normal limits (see Table 1).

Table 1. Anthropometric measurements of female students doing sports in a special health group (first year of studies)

By the second year of studies all subjects' weight, BMI and muscle mass indices decreased (p<0.05), the lowest values being recorded in the subjects diagnosed with vasomotor dyscrasia (p<0.05) (see Table 2).

Table 2. Anthropometric measurements of female students doing sports in a special health group (second year of studies)

The above alterations were caused by an increase in mental workload and physical loads and lifestyle changes. Eating behavior changes and health decline affect weight, BMI and muscle mass indices. According to the questionnaire survey conducted within the study the first year students' diet is not well balanced, most of them eat twice a day only [6]. Moreover, most of the surveyed students sleep for about 5 - 6 hours a day. Thus, total sleep time decrease and dietary changes directly influence the first-year students' metabolism resulting in weight loss and muscle mass reduction.

Cardiorespiratory system indices were studied during the study. In the first year of studies subjects diagnosed with scoliosis had a bigger lung volume than students with myopia and vasomotor dyscrasia and in comparison with the control group (p<0.05) (see Table 3). All subjects' systolic and diastolic blood pressure indices fell within the normal range, but resting diastolic pressure rates of the subjects with scoliosis were lower than those of the students with myopia (p<0.05).

The subjects with myopia had higher resting heart rate indices than those with vasomotor dyscrasia (p<0.05) proving that the cardiovascular system of the subgroup 3 subjects was undertrained.

The orthostatic test revealed that the subjects with scoliosis and vasomotor dyscrasia and reference group members showed a normal response to body position changes. However, the subjects with myopia had lower heart rate indices than those with vasomotor dyscrasia (p<0.05).

The above fact proves that the subjects diagnosed with scoliosis had some disorders in the cardiovascular system control and indicates the parasympathetic vascular control prevailing in the given subjects [5].

After fitness testing the highest heart rates were recorded among the subjects with vasomotor dyscrasia in comparison with the other examined students (p<0.05). It indicates that the students with vasomotor dyscrasia are most responsive to physical activity. Thus, a physical education teacher working with such students should carefully consider their physical well-being and choose adequate exercises to gradually build up mechanisms of adaptation of the cardiovascular system to exercise. 

Table 3. Fitness tests results of female students doing sports in a special health group (first year of studies)

It was found that the subjects with scoliosis demonstrated the shortest recovery time and the lowest heart rate indices during the recovery (p<0.05) while those with myopia were the longest-recovering ones after the graded exercise (20 squats) (p<0.05).

The following reliable data were obtained after testing second-year female students (see Table 4).

Table 4. Fitness test results of female students doing sports in a special health group (second year of studies)

We established a significant lung volume decrease in the subjects with scoliosis in comparison with the first-year female students (p<0.05).

The systolic pressure values of the subjects with scoliosis were proved to increase (p<0.05). Resting heart rate of all second-year subjects decreased (p<0.05) indicating to economization of their circulatory system performance [10]. At the same time the highest resting heart rate was typical of the subjects with scoliosis and myopia (p<0.05). 

All subjects demonstrated a reliable decrease in the heart rate indices after an orthostatic test (p<0.05). The obtained data indicate the dominance of the parasympathetic vascular control and the vascular response adaptive mechanisms being in decline among the second-year students.

Students are subject to extreme mental and physical stress while adjusting to a new environment in the first year of studies. As a consequence their nervous system is constantly stressed that results in a predominance of the sympathetic control of their cardiovascular system.

According to research data, the role of the sympathetic nervous system in the cardiovascular control goes down among the second-year students and, consequently, the parasympathetic nervous system takes up some control functions in order to keep the balance [11].

Conclusion. All subjects demonstrated positive changes as they exercised in accordance with the customized training program, the most significant alterations being decrease in weight, BMI and cardiorespiratory system indices (lung volume and heart rate before and after an orthostatic test).

The most evident positive changes were observed in the female students with the musculoskeletal disorder while subjects with eye diseases and vasomotor dyscrasia showed an evident negative response to function tests.

To sum it up, customized training programs for Physical Education classes help students adjust to a new environment during their studies and contribute to health and quality of life of first- and second year students with chronic diseases.

References

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Corresponding authors: konstanta2033@inbox.ru; kolesanna@mail.ru; olgapchelnikova@mail.ru)

 Abstract

A study of  body composition indices and cardiorespiratory system of first- and second year female students doing sports in a special health group has been carried out. It was found that all subjects showed an evident weight loss and a corresponding body mass index reduction as well as reduction of lung volume, resting heart rate and heart rate after an orthostatic test in the second year of studies. The most significant positive anthropometric and functional changes were found in the female students with the musculoskeletal disorders while those with eye diseases and vasomotor dyscrasia showed an evident negative response to fitness tests.

To sum it up, customized training programs for Physical Education classes help students adjust to a new environment during their studies and contribute to health and quality of life of first- and second year students with chronic diseases