A.I. Pavlik, associate professor, Ph.D.
State Research Institute of Physical Culture and Sport, Kiev, Ukraine
B.P. Yakovlev, professor, Dr.Psych.
V.V. Apokin, associate professor, Ph.D.
Surgut State University, Surgut

Keywords: ventilatory and gas exchange components, athletes, maximum athletic performance, training impact.                                                                                                             

Problem statement. Today the implementation of the system of training athletes is ineffective without knowing the specificity of manifestation of athletes' functional capacities influenced by training and especially competitive loads [1, 3]. This statement is most relevant for cyclic sports with primarily displayed endurance in which the volume and intensity of training impact have currently reached their maximum limit. For these kinds of sports functional capacities of the body in terms of manifestation of respiratory and circulatory systems of athletes are the most important factors for achieving high sports results. The training system is aimed at their proper formation during training [1, 2].

Due to lack or absence of objective and most complete information on the state and capacities of athletes’ bodies trainers try to compensate for the situation by unstructured or objectively unreasonable use of training means that are different in their effect on the body. This approach to planning of training does not always bring the desired results [3]. This is especially important with qualified athletes who are at the phase of training for achievements in elite sport or at the phase of maximizing individual capabilities. An essential fault of the unstructured approach to training arrangement is the lacking accurate quantitative understanding of the specifics of functional capabilities of athletes and hence the lack of the clear and specific justification of the choice of targeted training impact on the body. Therefore, the level of athletes' fitness can be determined by means of regular monitoring of their functional capabilities in terms of manifestation of respiratory and circulatory systems during the training process. Thanks to using such monitoring in the course of long-term training it can be objectified and made more efficient. Therefore, the findings of the current research on the effects of sports training on the body of a qualified athlete is a definition of the precise quantitative level of display of his functional capabilities as a result of the training process [1 – 3, 5].

The purpose of the research was to determine the ratio of functional manifestations of the ventilatory and gas exchange components of responses of the respiratory system of qualified athletes during exercise stress testing.

Materials and methods. The research was conducted in vitro in accordance with the program of milestone complete physical examination (MCPhE). One hundred and twenty-four athletes of cyclic sports were involved in it, their specialization related to mainly endurance sports and ranked Candidate Masters of Sports and Honored Masters of Sports.

Justification of the nature of this research is based on the assumption that one of the leading determinants of high results in cyclic sports is reaching a certain level of functional capabilities of athletes while training with regards to the way of functioning of the respiratory system influenced by physical activity. The most important property of its functioning in this case is their adequate in its impact reaction with regards to ventilatory and gas exchange components to its fulfillment. This reaction depending on the power of the work performed should be necessary and sufficient for the optimum process of oxygen diffusion in the lungs to ensure delivery of its required amount to the working muscles. Only some optimum value of the response of the ventilatory and gas exchange reaction of the body to physical impact can provide the most favorable maintenance of the respiratory homeostasis of the body [2]. Hence, the research of the adaptation of the respiratory system to the impact of particular physical activity is essentially determining the level of its functional manifestations and their correspondence to the optimal course of the whole set of its functional reactions, the most important of them being the optimal reaction of pulmonary ventilation and gas exchange of oxygen and carbon dioxide. The physiological nature of the long-term adaptation of the functional systems of athletes during training in this case is primarily to optimize the total performance of their reactive properties [2]. The results of the work performed in this direction helped define relevant quantitative indicators of the display of ventilatory and gas exchange components of the reaction of the respiratory system of qualified athletes at different levels of physical activity.

Functional capabilities of athletes with regards to the manifestations of the respiratory and circulatory systems were determined during the program of the running testing workouts, the leading one being exercise stress testing which should be performed to the point when an athlete is no longer able to maintain the given intensity (up «to the failure») [2]. The physical exercise was represented by a treadmill workout at the constant running speed of 10 km•hour^-1. The workout intensity gradually increased every 10 seconds by increasing the angle of slope of the treadmill by 1 degree per minute.

During testing of the athletes changes in the indicators of ventilatory and gas exchange components of reactions of functional manifestations of the respiratory and circulatory systems in response to the test workload was studied. The response of the athletes’ bodies to their impact was determined using instrumental research methods such as chronometry, ergometry, spirometry, gas analysis, pulsometry, mathematical statistics methods. 

The athletes were examined using a stationary gas analyzer «Oxycon Pro» and a running ergometer LE 500 (Jeager, Germany), and a telemetric heart rate analyzer Т31 «Polar» (Finland).

During the examination of the athletes with discrete time of 10 seconds a consolidated array of indicators was formed that reflects the functional manifestations of the respiratory and circulatory systems onto the test load. Along with a whole set of functional parameters, the leading among them being the value of maximum oxygen consumption (MOC), power of work was determined (Load [W]) and the corresponding manifestations of the ventilatory (respiratory minute volume) and gas exchange (exhaled oxygen and carbon dioxide) components of response of the respiratory system to physical load by such indicators as respiratory minute volume (V'E [L/mіn]), exhaled oxygen (FEO₂ [%]), and exhaled carbon dioxide (FECO₂ [%]). In accordance with the fact that the time of exercise stress testing is individual for each particular athlete and depends on his/her level of functional capabilities and fitness level, we used the last 8 minutes of the workout to analyze the results. In this period and particularly at the end of it athletes tend to reach their maximum athletic performance displaying the best of functional capabilities of their respiratory and circulatory systems.

The indicators of functional capabilities of the athletes were processed using the STATISTICA software, 6.1 [4].

Results and discussion. Research results indicate that during exercise stress testing of athletes up “to the failure” the time of the load execution in the given mode is in the range of 10 to 22 minutes. The maximum absolute workload power of the athletes was within 246-556 W. In its absolute value the difference of the indicators of the maximum and minimum power of athletes was 315 W. The average level of the maximum power achieved by the athletes during exercise stress testing was   ± σ = 420,6 ± 61,2 W (Table 1). Such results are pieces of evidence of different levels of manifestation of their functional capabilities while achieving the maximum individual athletic performance at the time of their testing.

The power of athletes’ work in accordance with the achieved indicators of the level of manifestation of the functional capabilities of the respiratory system in its ventilatory and gas exchange components of the response to physical activity compared in the last 8 minutes of the exercise stress testing also showed significant differences among the examined athletes with regard to the absolute values of the respiratory minute volume and exhaled oxygen depending on the particular level of the work power (Table, Figure 1). This reflects high values of the difference of the indicators in selected time intervals of the workout and indicates the multi-directional functionality of athletes at a certain level of athletic performance. This situation raises the question of determining the most optimal response of the respiratory system with regard to its ventilatory and gas exchange components to physical workload for the best realization of the functional capacities of athletes under physical load.

Figure 1 is a graph showing changes in such components of the response of the respiratory system as respiratory minute volume and exhaled oxygen. According to analysis of the graph, the overall trend of distribution of the parameters of the respiratory minute volume during exercise stress testing is in the fact that its absolute values increase progressively with an increase in the work power level of athletes. Athletes who have higher values of respiratory minute volume have a higher level of athletic performance. In the examined group of athletes the values of respiratory minute volume were within the range of 113 to 237 l·min^-1 as of the end of the work. The difference between its minimum and maximum values was 2.1 times, and in terms of the absolute value it was 124 l·min^-1.

Table.  Ratios of ventilatory and gas exchange components of response of respiratory system of qualified athletes to the intensity of work performed (during last 8 minutes) during exercise stress testing up «to the failure» (n = 124)

Figure 1. Ratios of the load (Load [W]) and ventilatory (V'E [L/min]) and gas exchange (FEO2 [%]) components of response of respiratory system of qualified athletes during exercise stress testing up «to the failure» (n = 124)

The average value of the respiratory minute volume of the athletes at the end of the workout was  ± σ = 166.1 ± 23.4 l·min^-1 with the average level of the maximum workout power being  ± σ = 421 ± 61.2 W.

Eight minutes before the end of the exercise stress testing the average value of the respiratory minute volume was  ± σ = 95.2 ± 13.5 l·min^-1 with an average workout power being  ± σ = 280 ± 54.7 W.

Subsequent analysis of the graph shown in Figure 1 indicates that the increase of work power results in an increase of absolute values of exhaled oxygen of athletes, indicating a decrease in gas exchange efficiency during exercise (oxygen utilization rate decreases). At the end of the workout the average value of exhaled oxygen was  ± σ = 17.31 ± 0.45 %. Its maximum value recorded with athletes at the end of the workout in this case amounted to 16.13 %, and the minimum value was 18.16 %. The spread in the absolute values of exhaled oxygen concentration of tested athletes was 2.03 %.

However, it should be noted that the increase in the exhaled oxygen concentration (reducing the difference between the inhaled and exhaled air concentration) indicates lower efficiency of the oxygen supply processes during physical activity. Bigger in its absolute value exhaled oxygen concentration promotes lower level of the athlete’s functional capabilities. In order to achieve higher oxygen consumption during exercise of set power an athlete should in this case be carried out by increasing the values of respiratory minute volume, that being an ineffective way of displaying athletic performance, and in the absence of such a possibility the athlete is forced to stop the workout. However, excessive increase of respiratory minute volumes (about 200 l·min^-1 and more) in this case is also an ineffective way of displaying athlete’s functional capacities. Therefore, to achieve higher athletic performance ventilatory and gas exchange components of the response of the respiratory system should be balanced to the utmost.

The other major component of the gas exchange response of the athlete’s body during a workout is exhaled carbon dioxide concentration. According to the study of the graph of changes in the values of its concentration during the exercise stress testing shown in Figure 2, in case of the absolute power level of the workout increasing the carbon dioxide concentration reduces progressively.

Figure 2. Ratios of the load power (Load [W]) and ventilatory (V'E [L/min]) and gas exchange (FEO₂ [%]) components of response of respiratory system of qualified athletes during exercise stress testing up «to the failure» (n = 124)

At the end of the workout its average value was  ± σ = 4.05 ± 0.52 %. The individual maximum carbon dioxide concentration shown by the athletes was 5.28 %, and the minimum one was 2.99 %. In other words, differences in the absolute values of gas concentration during the same functioning conditions of athletes at the end of the workout amounted to 2.29 %.

Carbon dioxide concentration in athletes started to decline with the power of the workout being at the level of 320 W. At this point, the value of its concentration was  ± σ = 4.55 ± 0.54 % given the maximum value being 5 %, and the minimum - 4 %. Within the power increase range of 320 to 420 W the reduction of the carbon dioxide concentration was 0.5 %.

Thus, thanks to the findings the effectiveness of manifestations of the ventilatory and gas exchange components of response can be determined and evaluated while testing athletes’ functional capabilities. Such average values of indicators and ratios of their change limits with regard to the power of increasing workload and the relevant values of respiratory minute volumes, oxygen and carbon dioxide concentration during the last 8 minutes of its execution for each of its 10 second intervals make it possible to use them as reference values to determine the effectiveness of the functional responses of the respiratory system during physical exercise performed by athletes. 

Conclusions. The given functional indicators of the ventilatory and gas exchange components of the responses of the respiratory system during exercise stress testing suggest that they have an effect shown in varying degrees on reaching of the maximum athletic performance. The results obtained can help, if necessary, select individual targeted exercises for athletes during training to achieve the necessary levels of of the ventilatory and the gas exchange components of the response of the respiratory system.

References

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2. Adaptation in sport / V.N. Platonov. - Kiev: Zdorov'e, 1988. – 216 P. (In Russian)
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4. Khalafyan, A.A. STATISTICA 6. Statistical data analysis: textbook, 3rd ed. – Мoscow: Binom-Press, 2008. – 512 P. (In Russian)
5. Powers, S.K. Beadle, R.E. Control of ventilation during submaximal exercise: а brief review // J. Sport Sience. – 1985. Spring. – Vol. 3 (1). – P. 51 – 65.

Corresponding author: antvpavlik7@gmail.com