Dr.Biol., Professor A.A. Pseunok¹
Ph.D., Associate Professor A.D. Gayrabekov^2
1Adyghe State University, Maikop
²Chechen State University, Grozny

Keywords: cardio-respiratory system, heart rate, training load, adaptive mechanisms, ontogenesis, tension index, vital capacity, sambo wrestlers

Introduction

It is a matter of common knowledge that motor activity is one of the key factors in cardio-respiratory system formation process that largely determines its structure and functionality [3, 10]. This is the reason why modern sport science attaches so much importance to the studies of the children’s and adolescents’ abilities to adapt to physical workloads.

The functional and reserve capacities of the human body are known to largely depend on how well its cardio-respiratory system adapts to different intensity levels of motor activity. Therefore, sport science gives top priority to studies of the cardio-respiratory system that are considered of high practical importance for sport physiology in many aspects including the individual physical workload control systems to ensure training and sport teaming processes being highly effective [1,2].

The purpose of the study was to explore the adaptive capabilities of junior sambo (acyclic sport discipline) wrestlers based on the cardio-respiratory system performance criteria.

Materials and methods of research

Subject to the study were young athletes engaged in the ongoing training process on a regular basis and having practical experience of participation in regional and national sambo competitions. Sport records of the young athletes at the moment of the study were at least 2 years long. The athletes were subject to regular comprehensive health tests and medical examinations at the Adygei Republican Centre of Preventive Medicine and were rated with Class 1 and Class 2 Health Groups as verified by their health records. Every athlete agreed to participate in the study as stated in the relevant family consent in writing.

The junior 12-14 years-old sambo wrestlers are trained starting from 3 times per week for 1.5 hours, with about half an hour in every training session being scheduled to relay races and active games. Training workloads are stepped up in a phased manner so that the 13 year-olds are trained 5 times a week, each training session time coming to 2-2.5 hours. Strong emphasis in the training process is being placed on the general physical conditioning and special practices. Warm-up practices and core part of the training routine are performed in the collective group.

Reference group for the study was composed of the 12-14 years old students trained under the standard program.

We used the R.M. Baevskiy’s method for the heart rate tests. Young athlete was required to relax for 5  minutes in a sitting position and then his/her electrocardiogram (ECG) was recorded for 2 minutes in the second standard format using “PolySpectrRhythm” Electrocardiograph and Toshiba L30 computer equipped with the relevant ECG processing software. Subject to registration were 128 sequential cardio-intervals (the R-R complexes). In the next stage of the test, the athlete performed 30 deep squats for 30 seconds, immediately followed by the repeat ECG test.

In the heart rate tests, the following indices were metered: Mode (Мо) meaning the most common cardio-interval value; Mode Amplitude (МоA) that means the ratio of the cardio-intervals of the subject mode in the total number of cardio-intervals in the array, in percentage terms; Variation Range (ΔХ) meaning the difference between the minimum and maximum values of the cardio-intervals; and the Tension Index (TI). In addition, the following indices were metered: Vegetative Balance Index (VBI); Vegetative Rhythm Index (VRI); Regulation Process Adequacy Index (RPAI); Heart Rate (HR); and Heart Rhythm (HRh) indices; A1 means herein the autumn of the first test year; S1 spring of the first test year; A2 autumn of the second test year; and S2 spring of the second test year.

External respiration system functionality was quantified by tests of forced vital capacity (FVC), respiratory volume (RV) and inspiratory reserve volume (IRV). The tests were performed using “Spiro-Spectrum” Test Unit made by NeuroSoft Company, computer and the relevant application software.

The outcome test data were processed using the variation statistics method with the following calculated indices: mean arithmetic error (М) of the mean arithmetic value (m); the Student’s reliability criterion (t) and the probability index (Р).

Study results and discussion

Heart rhythm dynamics of the 12-14 years old sambo wrestlers

The outcome data of the tests give good grounds for a few conclusions on the condition of the heart rhythm (HRh) regulation mechanisms of the junior sambo wrestlers. Having analyzed the heart rate (HR) data of the 12-14 years-old athletes in relaxation phase, we would emphasize that the heart rates notably reduced by the fourth training macro-cycle compared to the initial HR data readings (Figure 1).

Controlled training workloads in the first test year result in some HR increase (Р>0.05) (Figure 2). In the second test year, the HR readings show no meaningful variations, and this fact is indicative of the positive sport fitness trend: i.e. the higher is the sport fitness level, the lower is the HR-metered response to physical workloads.

It should be noted that similar positive trends were detected by a few other researchers [12, 14].

Figure 1. Resting heart rhythm dynamics of 12-14 years-old sambo wrestlers

Note: Difference reliability for the indices: n refers to rest phase and post-exercise phase; m refers to the 1^st and 2^nd test years; v refers to the yearly data

Having analyzed the performance of the sympathetic and parasympathetic divisions of the ANS at rest, we would note stabilization of the first division and drastic activity increase of the second division by the fourth macro-cycle (P<0.05) (Figure 1). It may be indicative of new regulatory mechanisms being established under the influence of regular muscular exercises associated with the higher vagal tone and, as a result, more economic functioning of the relevant body systems. It is a commonly known fact that systemic muscular workloads tend to improve functional capacity of the heart at relative rest; and our case is no exclusion as verified by the expressed drop in the HR (with P<0.05). Furthermore, as demonstrated by a few studies, bradycardia associated with training process occurs in the context of the natural fall of the HR with age and with growing daily motor activity [4, 9, 11]. On the other hand, the lower sympathetic influences, the higher vagotonic ones and the general weakening of the central regulatory mechanism may be indicative of the general decrease of the cardiovascular system activation level that may be a testimony to some body fatigue. Some researchers noted that low TI (Tension Index) values are associated with serious fatigue of parasympathetic type when enforcement of the parasympathetic tonus leads to metabolic process intensity decrease in the myocardium, and this mechanism effectively protects the body from excessive waste of energy [6, 8].

Controlled training workloads result in notable changes in the VRI values by the end of the second and fourth training macro-cycles, with its notable shift towards the parasympathetic nervous system when nearing the second macro-cycle, followed by a shift towards the sympathetic one within the second macro-cycle (P<0.05) (Figure 1). This response is more typical for the 12-14 years-old athletes.

Tension index shows insignificant variations in both the rest phase and post-exercise phase (P>0.05) that may be indicative of the low degrees of engagement of the cortico-limbic structures in the heart rhythm regulation process (Figures 1, 2). Some studies assume that the increased activity of the sympathetic division of the ANS unsupported by the central regulatory mechanism activation may be interpreted as the heart rhythm control mechanism failure or malfunction [13].

Figure 2. Post-exercise-phase heart rhythm dynamics of 12-14 years-old sambo wrestlers

Note: Difference reliability for the indices: n refers to the rest phase and post-exercise phase; m refers to the 1^st and 2^nd test years; v refers to the yearly data

The increased number of vagotonics at rest may be indicative of the growing number of athletes with low functional potential by the fourth training macro-cycle (Figure 3).

Figure 3. Resting Tension Index (std. units) variation diagram for 12-14 years-old sambo wrestlers

It is obvious that this period is the time when the ability to stand physical workloads reaches its minimum; and for this reason the training process in this period shall be prudently designed to prevent possible de-adaptation process.

In the beginning of the first and third macro-cycles, the post-exercise sympathicotonic group accounts for 20.25% of the data array. We would explain this fact by the increased emotional tension since it is the time when competitions are quite frequent (Figure 4). V.P. Kaznacheev (1974) believes, the cardio-regulatory mechanism restructuring with the increased role of central elements may be indicative of situations of critical tension [7].

Figure 4. Post-exercise-phase Tension Index (std. units) variation diagram for the 12-14 years-old sambo wrestlers

The outcome data of the study demonstrate that it is the age of 12-14 years that shall be considered the critical phase in the ontogenesis process when one set of regulatory mechanisms is broken down and replaced by the new one. Inadequate design and control of the training workloads in this sensitive stage may result in the body reserves being depleted in the context of low energy generation potential that may manifest itself in the catabolic processes being slowed down. This process may be of high health risk for junior athletes. It means that their functional capacities need to be closely monitored to assess adequacy of their body responses to the applied training and competitive workloads.

Variations of the respiratory system indices for the 12-14 years-old sambo wrestlers

Having analyzed the variations of the respiratory system indices for the 12-14 years-old sambo wrestlers, we should mention that the Vital Capacity Index (VCI) notably grows by the fourth training macro-cycle (P<0.05) (Figure 5).

The constant growth of the VCI throughout the four macro-cycles, with the absolute growth values being expressly higher than that of the non-sports peers from the reference group, may be considered an important adaptive variation supported by not only the ontogenetic development process logic, but the impacts of special training workloads on the junior sambo wrestlers too. Respiratory rhythms of the newcomers during the bouts are very frequent and intermittent, whilst the special fight situations (including throws, wrestler’s bridges etc.) normally claim less than 65-80% of the vital capacity as demonstrated by N.D. Graevskaya (1986) in her studies.

In the first and second macro-cycles, the External Respiration Volume (ERV) tends to increase (P<0.05). At the same time, the Respiratory Volume values are lower than in other age groups although show a smooth growth over the period under study (P>0.05) (Figure 5).

Figure 5. Variations of the respiratory system indices(litres) for 12-14 years-old sambo wrestlers

Note: Difference reliability for the indices: n refers to the rest phase and post-exercise phase; m refers to the 1^st and 2^nd test years; v refers to the yearly data

The ERV sagging trend (P>0.05) may be attributed to the reserve potential of the respiratory system being decreased in the period of active growth process that may be associated with drops in the biomechanical body factors, some constraints in the respiration system functionality under physical workloads and some slowing down of the natural recreation processes [5].

The notable increase of the respiration biomechanics criteria (VC) is indicative of the positive response of the respiratory system of 12-14 years-old adolescents to the sambo training process. The variations detected by the study demonstrate, on the one hand, that the junior sambo wrestlers show significantly better physical qualities (as verified by the VC indices) than their non-sports peers; and, on the other hand, that their rest-phase breathing is frequent and superficial that may be characteristic of some tension in the lung respiration functionality, the conclusion being supported by a few other researchers [5].

Conclusion

The study demonstrates that the sambo training system activates central regulatory mechanisms in 20.25% of the junior athletes at the beginnings of the first and third macro-cycles that may be indicative of some tension. Vital capacity is increased by the end of the fourth macro-cycle, and this development may be interpreted as an important adaptive variation triggered by not only the ontogenetic development process, but the impacts of special training workloads on the junior sambo wrestlers too. The positive development trends of the respiratory system biomechanical functionality factors under the physical workloads are attributable to the special training practices with an emphasis on the shoulder girdle. The physical workloads specific for this acyclic sport discipline are found to step up the general body functionality and non-specific resistivity that helps the body more efficiently adapt to the training and competitive workloads. Findings of the study will be beneficial for the training process optimization initiatives with an emphasis of the injury-prevention aspect.

Therefore, the study of the cardio-respiratory system dynamics in the training process give the important data indicative of the adolescent body adaptive capabilities under physical workloads, the training workload tolerance criteria and potential deregulation conditions that may arise in the process.

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Corresponding author: Pseunokk@mal.ru