Dr.Biol., Professor R.V. Tambovtseva¹
PhD, Associate Professor V.R. Orel^1
1Russian State University of Physical Education, Sport, Youth and Tourism (GTSOLIFK), Moscow

Keywords: archers, expander drawing, stroke volume, elastic resistance, peripheral resistance, cardiac output.

Introduction. The integrated research on the central hemodynamics and cardiovascular load in athletes of various specializations, as well as on their skill levels, has been conducted for many years now [2-7]. However, there is practically no data on the central hemodynamics and cardiovascular load indices in elite archers at the bowstring drawing moment. It is difficult to measure the peripheral and elastic resistance indices when drawing a bowstring due to the need to measure blood pressure, which is almost impossible as both hands are usually used to draw a bow. An archer also holds his/her breath at the aiming moment, resulting in oxygen deficiency. Comprehensive research of the effect of central hemodynamics and cardiovascular load of the athletes on the adaptability of the cardiovascular system to physical loads largely determine the possibilities of effective performance of competitive and physical loads. At the same time, the lack of knowledge on this problem prevents us from carrying out a quantitative control of the circulatory system adaptability. The set of physiological indicators under study is significantly limited even in the biomedical and physiological research of the circulatory system responses to physical loads,.

Objective of the study was to analyse strain effects on central hemodynamics and cardiovascular load indices in elite archers.

Methods and structure of the study. The experiment was conducted in the Sports Performance Laboratory of the SRI of Physical Culture and Sport. The study was conducted without risking people’s health in compliance with the relevant ethical and humanity provisions (2000 Helsinki Declaration, EU Directive 86/609). The subjects gave a written consent to participate in the experiment. The study involved 19 elite archers. At the time of the examination the subjects were healthy, and were medically approved to participate in the experiment.

It is difficult to measure the peripheral and elastic resistance indices when drawing a bowstring due to the need to measure blood pressure, which is almost impossible as both hands are usually used to draw a bow. To simulate the expansion of the bowstring we used an expander with one end being firmly fixed and the other end being drawn with one hand to simulate the bowstring expansion, so we could measure blood pressure on the free hand. The expander drawing force equaled 11-12 kg in all the athletes.

Measurements of the central hemodynamics indices – stroke volume (SV) and cardiac output (CO), as well as heart rate (HR) and main phases of the cardiac cycle were made using the tetrapolar rheography method [1]. We applied special software tools to compute the elastic (Ea) and peripheral (R) vascular resistance rates based on the systolic and diastolic blood pressure rates. The obtained blood pressure indices (systolic - SBP and diastolic - DBP) were entered into the online database of the RHEODYNE soft-hardware complex. Then we input the rheographic indices (within 30-40 sec). Similarly, while the subject drew the expander with his/her right hand, we measured blood pressure on his/her free left hand and entered the indices into the database table of the RHEODYNE complex. Simultaneously, we input the rheographic indices of the central pulse in the expander drawing phase.

Results and discussion. Table 1 presents the average values ​​and standard deviations of the central hemodynamics (HR, SBP, DBP, SV, CO) and cardiovascular load (Ea and R) indices registered in the archers prior to and during proper expander drawing with the right hand. HR was proved to increase significantly from 78.1 to 106.8 bpm (p<0.001) in the expander drawing phase. In turn, the elastic resistance Ea increased statistically significantly from 1132 to 1436 dyn×cm^-5 (p<0.001), and the peripheral vascular resistance increased significantly from 1232 to 1395 dyn×cm^-5 (p<0.001). Consequently, the cardiovascular load increased significantly during expander drawing as compared to the data obtained prior to expander drawing. These results are fundamentally different from those obtained during the dynamic muscular work, when a significant decrease in the peripheral resistance was observed.

Table 1. The central hemodynamics and cardiovascular load indices in the archers prior to and during expander drawing with one hand

 *** – significance of differences p<0.001.

In this setting, stroke volume decreased statistically significantly from 92.9 to 56.4 ml (p<0.001), and cardiac output - from 6.36 to 6.0 l/min (p<0.01).

Table 2 lists the average values and standard deviations of the central hemodynamics (HR, SBP, DBP, SV, CO) and cardiovascular load (Ea and R) indices registered in the archers during and right after expander drawing with the right hand.

Table 2. The central hemodynamics and cardiovascular load indices in the archers during and right after expander drawing

*** – significance of difference. p<0,001; ** – р<0.01.

It is shown that after expander drawing HR decreased from 106.8 to 105.3 bpm, and the SBP and DBP values ​ increased significantly (p<0.01). The elastic and peripheral vascular resistance increased statistically significantly from 1436 to 1638 dyn×cm^-5 (Ea) (p<0.001) and from 1232 to 1395 dyn×cm^-5 (R) (p<0.001). At the same time, the cardiovascular load was characterized by higher values ​​in the expander drawing phase as opposed to the data in Table 1. In this setting, SV and CO decreased on the average from 56.4 to 54.8 ml and from 6.00 to 5.75 l/min, respectively. Table 3 lists the coefficients of pair correlation between the central hemodynamics and vascular resistance indices prior to expander drawing, with an average number of cardiac cycles of the athletes not less than n=103. Practically all correlation coefficients were statistically significant at the significance level of p<0.001.

Table 3. The coefficients of pair correlation between the central hemodynamics and vascular resistance indices prior to the expander drawing phase

It is shown that an increase in the HR values is statistically significantly associated with an increase in the peripheral and elastic vascular resistance indices, as well as with a decrease in the stroke and cardiac output indices. In turn, an increase in the elastic resistance Ea is significantly associated with an increase in the peripheral resistance R, as well as with a significant decrease in the SV and CO values. Table 4 presents the coefficients of correlation between the indices presented in Table 3, in the expander drawing phase.

Table 4. The coefficients of pair correlation between central hemodynamics and vascular resistance indices in the expander drawing phase

In contrast to the data obtained prior to the expander drawing phase (see Table 3), HR (see Table 4) and peripheral resistance, as well as CO were hardly correlated (p>0.1), while the correlation relations with other parameters did not change, remaining at the same high level. The regression relations between SV and HR indicate that an increase in HR is associated with a decrease in SV both prior to and during expander drawing with the ongoing efforts. In terms of changing Ea - from 1100 to 1750 dyn×cm^-5 (Ea changing from the optimal to sub-hypertonic levels), the SV values ​​are rather closely interrelated both prior to and during expander drawing. The maximum SV values ​​of about 78-82 ml are attained at the optimal Ea values ​​of about 1100 dyn×cm^-5. Any further increase in Ea causes a steady decrease in SV from 45 to 30 ml. Such low SV values ​​are attained when the Ea values in individuals with arterial hypertension exceed 2000 dyn×cm^-5. At the same time, the blood pressure rates are within the normal range both in the expander drawing and recovery phases, although the elastic resistance values reach the hypertonic rates. SV reaches the minimum values ​​from 30 to 40 ml when the elastic resistance values reach the hypertonic rates from 2000 to 2800 dyn×cm^-5. The increase in the elastic resistance Ea is associated with a decrease in CO both prior to and during expander drawing with the ongoing efforts. In terms of changing Ea - from 1100 to 1750 dyn×cm^-5, the Co rates ​​are rather closely interrelated both prior to and during expander drawing.

Any further increase in Ea leads to a steady decrease in the cardiac output - from 4.5 to 3.0 l/min. Such low CO values are reached when the Ea values in individuals with arterial hypertension exceed 2000 dyn×cm^-5. The maximum CO values of about 7.8-8.5 l/min are attained at the optimum Ea values of about 1100 dyn×cm^-5.

The increase in the elastic resistance Ea is accompanied by the increase in the peripheral resistance R both prior to and during expander drawing with the ongoing efforts. In terms of changing peripheral resistance rates - from 1100 to 1750 dyn×cm^-5, the elastic resistance rates turn out to be rather closely interrelated both prior to and in the expander drawing phases. Any further increase in the peripheral resistance R results in a steady increase in the elastic resistance Ea - from 1750 to 2750 dyn×cm^-5. Such high Ea values ​​are attained when the R values in the subjects with arterial hypertension exceed 2000 dyn×cm^-5.

  Conclusions:

• The archers’ vascular resistance rates vary in a wide range from the optimal/ normal levels to sub-hypertonic and hypertonic rates. At the same time, the systolic and diastolic pressure stays within the normal range prior to and in the expander drawing phase and in the recovery phase.
• The stroke volume and cardiac output rates were found to significantly fall with the growth of the elastic and peripheral arterial system resistance rates.

References

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Corresponding author: ritta7@mail.ru

Abstract

Objective of the study was to analyze strain effects on central hemodynamics and cardiovascular load indices in elite archers. The central hemodynamics indices including stroke volume (SV), cardiac output (CO), heart rate (HR) and key phases of cardiac cycle were obtained using tetrapolar rheography. We applied special software tools to compute elastic (Ea) and peripheral (R) vascular resistance rates based on the systolic and diastolic blood pressure indices. The study data showed that the vascular resistance indices vary in a wide range from the optimal/ normal levels to sub-hypertonic and hypertonic rates, with the systolic and diastolic blood pressure staying within the normal range prior to and in the expander drawing phases and in the recovery phase. The stroke volume and minute rates were found to significantly fall with growth of the vascular resistance rates.