PhD, Professor V.A. Vishnevsky¹
PhD, Associate Professor V.V. Apokin¹
T.E. Gafiyatullin^1
1Surgut State University, Surgut

Keywords: cyclic work in closed power loop, hysteresis loop.

Background. Our prior studies [1] to rate benefits of the cyclic work tests in closed power loops [2, 3, 5] found that the isometric-acceleration load growth phase line angle depends on the individual adaptability, vegetative balance and muscular tissues; whilst the isometric-acceleration load fall phase line angle basically depends on the individual aerobic capacities. The hysteresis loop square was found to reflect the all-round working capacity, control systems performance and energy costs of the bodily functions. At the same time, it is still unclear whether such aspects as gender, initial work power, and type of muscular activity affect the prognostic potential of the tests, which was the subject to this study.
Objective of the study was to identify the gender-, initial-power- and muscular-activity-specific effects on the prognostic potential of the tests.
Methods and structure of the study. Sampled for the study were 45 sporting students of Surgut State University majoring in different disciplines and having different sport qualifications. We applied our own adapted version of cycle ergometer test with closed power loop to rate the bodily physiological reserves. The initial load power was selected versus body mass as provided by the V.L. Karpman classification matrix [3]. At the first stage of the experiment, we conducted a comparative analysis of the main test rates in the male (n=24) and female (n=21) students. The subjects were to perform a step test on a cycle ergometer TechnoGym with the loads increased and decreased in five 15W steps, each step taking 2 minutes. After each load step, their heart rate (HR) was recorded using Pollar cardio tester. At the second stage, the male and female samples were divided into approximately equal groups in the lower and higher initial power modes. At the third stage, we formed an Experimental Group (EG) (n=31), which participants were to perform the cycle ergometer test with allowance for their body mass, followed by two treadmill tests. In the first loading phase, the initial speed was selected so that the pulse corresponded to HR at the first step of cycle ergometer test. Then, with a constant speed, the pitch angle of the treadmill was changed (3, 6, 9, 12, 15, 12, 9, 6, 3 degrees). In the second loading phase, the initial speed was selected in a similar way, and then, simultaneously with an increase in the pitch angle, the speed was changed by 0.6 km/h.
The hysteresis loop generated by the test was analyzed by the software we had designed in cooperation with O.V. Vishnevskiy, research associate of the Cytology and Genetics Research Institute of the Russian Academy of Sciences. The software enables to obtain such key parameters as the pitch angle in the isometric-acceleration load growth phase (α), pitch angle in the isometric-acceleration fall phase (β); and square of the hysteresis loop (S). The prognostic potential of individual hysteresis loop parameters was evaluated using a descriptive statistics method, Student t-test, and correlation analysis.
Results and discussion. The results of comparative analysis of the main cycle ergometer test rates in the males and females are presented in Table 1.

Table 1. Results of analysis of main hysteresis loop parameters in males and females during cyclic work in closed power loop

The data indicate that the pitch angle in the isometric-acceleration load growth phase (α), characteristic of the individual metabolic processes, individual adaptability, vegetative balance and muscular tissues, was significantly lower in the males. Since the age and sport qualifications in the samples did not differ significantly, we primarily associate higher rates in the male athletes with the larger muscular mass (t=3.44, p<0.05). At the same time, the hysteresis loop square (S), characteristic of the bodily internal functionality, overall physical working capacity, status of the regulatory systems, and the degree of economization of the bodily functions, was tested lower in the females – that may be attributed, fist of all, to the fact that the initial load power had been selected based on their body mass rates. Since it is generally lower in females than in males (61.4±8.5 kg versus 71.2±4.6 kg, t=-3.98, p<0.05), we would expect lower pulse cost of work. However, HR in the first loading phase did not differ significantly in both females and males (108.5±18.8 bpm versus 112.6±14.8 bpm, t=-0.79, p>0.05). Therefore, we attribute the lower bodily internal functionality in females to the higher conservativeness of a female body. The pitch angle in the isometric-acceleration load fall phase (β) is mainly associated with the rate of recovery of metabolic processes, which means that it directly depends on the aerobic capabilities of the body. As the MOC levels in the studied groups was almost identical (t=0.02, p>0.05), we did not observe any significant differences between the males and females in terms of this parameter.
To study the effects of the initial load power on the test results, the male and female samples were divided into the groups working in the lower and higher initial power modes. In these groups, we analyzed the hysteresis loop parameters, as well as HR at the initial load power, at the peak of loading and at the end of testing. The analysis results are presented in Table 2. According to the findings, the initial load power did not significantly affect either the hysteresis loop parameters or HR. Although according to the hysteresis loop square and HR values at the end of the curve slope at the stage of recovery, there was a clear tendency towards its increased influence.

Table 2. Results of analysis of main hysteresis loop parameters in males and females depending on initial cycle ergometer load power

The muscular-activity-specific data are presented in Table 3. The analysis of the role of the type of muscular activity revealed that, despite the complete correspondence of the baseline HR values in each of the test versions, the isometric-acceleration load growth phase angle (α) differed statistically significantly. At the same time, we did not find any significant correlations between the angle α and hysteresis loop parameters in the run version of the cycle ergometer test, although the correlation between the two versions of the run test was significant (r=0.678, p<0.01). The isometric-acceleration load fall phase angle (β) was significantly larger in the run versions of the test. Moreover, no significant correlations between various test versions were detected. The hysteresis loop square (S) in the cycle ergometer test was found to correlate both with the first (r=0.455, p<0.01) and second (r=0.561, p<0.01) version of the run test.

Table 3. Results of analysis of main hysteresis loop parameters depending on type of muscular activity

Conclusion. The obtained results confirmed the prognostic potential of individual hysteresis loop parameters and emphasized the need to consider gender characteristics and types of muscular activity when interpreting the results of the cyclic work tests in closed power loops.

References

1. Vishnevskiy V.A. Prognosticheskie vozmozhnosti proby s tsiklicheskoy rabotoy, vypolnyaemoy po zamknutomu tsiklu moschnosti [Cyclic workout test with closed power loop: performance forecast application]. Teoriya i praktika fiz. kultury. 2017. no.  11. pp. 83-85.
2. Davidenko V.I., Mozzhuhin A.S., Telegin V.V. Sistema fiziologicheskih rezervov sportsmena [Athlete's system of physiological reserves]. Kharakteristika funktsionalnykh rezervov sportsmena [Characteristics of athlete' functional reserves]. Leningrad: GDOIFK publ., 1982. P. 3.
3. Davidenko D.N., Rudenko G.V., Chistyakov V.A. Metodika otsenki mobilizatsii funktsionalnykh rezervov organizma po ego reaktsii na dozirovannuyu nagruzku [Methods for assessing mobilization of body functional reserves by its response to graded load]. Uchebnye zapiski universiteta im. P.F. Lesgafta. 2010. no. 12 (70). pp.  52-57.
4. Karpman V.L., Belotserkovskiy Z.B., Gudkov I.A. Testirovanie v sportivnoy meditsine [Testing in sports medicine]. M.: Fizkultura i sport publ., 1988. pp. 21-46.
5. Yakovlev G.M., Andrianov V.P., Lesnoy N.K. Novy metodicheskiy podkhod v issledovanii adaptatsii sistemy krovoobrashcheniya k tsiklicheskoy fizicheskoy nagruzke [New methodological approach to study of adaptation of circulatory system to cyclic exercise]. Kharakteristika funktsionalnykh rezervov sportsmena [Characteristics of athlete' functional reserves]. Leningrad, 1982. pp.  83-88.

Corresponding author: apokin_vv@mail.ru

Abstract
Our prior studies to rate benefits of the cyclic work tests in closed power loops found that the isometric-acceleration load growth phase line angle depends on the individual adaptability, vegetative balance and muscular tissues; whilst the isometric-acceleration load fall phase line angle basically depends on the individual aerobic capacities. The hysteresis loop square was found to reflect the all-round working capacity, control systems performance and energy costs of the bodily functions. The study was designed to analyze the age-, initial-power- and muscular-activity-specific data obtainable from the hysteresis loop for the cyclic work in closed power loop. The cycle ergometer tests found the isometric-acceleration load fall phase angle (characteristic of the individual metabolic processes) being significantly lower in the males – apparently due to the larger muscular mass (47.20±4.62 versus 41.31±6.53%, p<0.05). The hysteresis loop square (S) characteristic of the bodily internal functionality was tested lower in females – that may be attributed to the higher conservativeness of a female body under the same HR. The isometric-acceleration load fall phase angle indicative of the metabolic process rehabilitation speed was found gender-unspecific – as well as the maximal oxygen consumption rate (50.99±10.36 and 51.97±13.03 ml/kg/min, p>0.05). The initial power was found to cause insignificant effect on the hysteresis loop parameters, with the absolute load growth and fall angles in the cycle ergometer and run tests tested virtually the same. The hysteresis loop square (S) in the cycle ergometer test was found to correlate both with the first (r=0.455, p<0.01) and second (r=0.561, p<0.01) version of the run test.