Peculiarities of Adaptation to Training Loads in Paralympian
Cross-country Skiers with Visual Impairment versus Able-bodied
Athletes based on Analysis of Heart Rate Variability Data
Vladislav Bakayev and Alexander Bolotin
Institute of Physical Education, Sports and Tourism, Peter the Great St. Petersburg Polytechnic University,
St. Petersburg, Russian Federation
Keywords: Paralympian Cross-country Skiers with Visual Impairment, Heart Rate Variability, Peculiarities of
Adaptation to Training Loads.
Abstract: An increasing number of people with impaired vision who engage in skiing sports dictates a pressing need
to study the athlete’s physiologic functioning in conditions of sensory insufficiency. In the course of the
adaptation to training and competition conditions, unlike able-bodied athletes, blind and visually impaired
people use compensatory mechanisms to replace the lost visual function. This fact contributes to the
development of the structural trace of adaptation to loads and has to be considered in training of this
category of athletes. The study involved 42 skiers. The experimental group (EG) comprised Paralympians
with visual organ impairment (n=23), whereas the control group (EG) comprised athletes from the Russian
Federation national cross-country skiing team (n=19). The research included an examination of the heart
rate variability using Kardiometr-MT computer analyzer by TOO Mikard Lana at rest, immediately
following the training, and before competition, and an examination using FirstBeat SPORT computer
system for determining the training effect and overnight recovery on a daily basis during 7 days of the
training camp. The obtained results are indicative of higher “price” of adaptation to the conditions of sports
practice in Paralympic skiers with visual function impairment versus able-bodied athletes.
1 INTRODUCTION
Sports activities of Paralympian cross-country skiers
with visual impairment, being one of the aspects of
physical activity in people with disabilities, are
related to high physical and psychological loads,
which contribute to specific adaptive responses of
the persons with disabilities to training loads they
encounter (Bakaev et al., 2015, Bernardi et al., 2010,
Bernardi et al., 2012, Tweedy, 2011, Laaksonen et
al., 2018). Optimization of visually impaired
Paralympian skiers’ performance in competitions
requires studying the peculiarities of their
psychomotor function, psychophysical stamina,
central nervous system throughput and functional
asymmetry of the athlete’s body.
Training practice of visually impaired
Paralympian skiers is based on the diagnosis of the
athletes’ condition for management of various
aspects of their fitness according to model
characteristics. Such an approach to the training
process requires development of novel methods of
training and recovery after a physical performance,
as well as for objective monitoring of impact
training loads have on the athlete’s physiology
(Bakaev et al., 2016, Bakayev et al., 2018, Bolotin,
2017a, Bolotin, 2017b, Edmonds et al., 2014,
Malcata and Hopkins, 2014, Sanz-Quintoet al.,
2018). Therefore, it is necessary to find specific
optimal loads as a background for developing the
most appropriate specific physiological structure for
visually impaired Paralympian skiers ensuring their
achievement of highest possible results. Another
issue to be considered in this relation is reciprocal
limitation of certain motor capabilities in athletes,
when progress in one capability reduces the level of
the other (Bolotin and Bakayev, 2017c, Ivashchenko
et al., 2017, Hopkins et al., 2009, Hynynen et al.,
2006).
It is common knowledge that the stages of
adaptation are inextricably interconnected and
coordinated in the framework of the single adaptive
physiological response in visually impaired
Paralympian skiers. Adaptation includes shaping of
132
Bolotin, A. and Bakayev, V.
Peculiarities of Adaptation to Training Loads in Paralympian Cross-country Skiers with Visual Impairment versus Able-bodied Athletes based on Analysis of Heart Rate Variability Data.
DOI: 10.5220/0008065601320137
In Proceedings of the 7th International Conference on Sport Sciences Research and Technology Support (icSPORTS 2019), pages 132-137
ISBN: 978-989-758-383-4
Copyright
c
2019 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved
a certain dominant functional system (Hoffman and
Street, 1992). This thesis is critical for adaptation to
the training and competitive stress in blind
Paralympian skiers. In the process of adaptation, a
visually disabled person forms new functional links
and dominant functions, which help the athlete,
master a qualitatively new sports skill. Thus, long-
term adaptation allows athletes to perform the earlier
impossible work in conditions of visual deprivation.
Forming new links is a decisive factor in the process
of expansion of bodily reserves, leading to
economical functioning of the systems responsible
for the process of adaptation.
In the course of long-term adaptation, reserve
exhaustion and (over)recovery cycles must be taken
into account for training sessions planning
(Gorshova et al., 2017). One of the major tasks is to
avoid (or delay as much as possible) the fourth
stage, i.e. the adaptation collapse.
The adaptation collapse in athletes manifests in
overstraining various systems and organs, and in the
overtraining syndrome (Sattlecker et al., 2009,
Malcata, 2014). In most cases, visually impaired
Paralympian skiers overstrain their central nervous,
immune, cardiovascular, and musculoskeletal
systems. One of the modern theories explaining
development of overtraining in athletes is the
vegetative disorder theory. Pronounced activation of
the sympathetic nervous system under the influence
of training and competition can result in its
exhaustion. Decrease in sympathetic activation and
reciprocal domination of parasympathetic activation
can cause inhibition of a number of bodily systems,
fatigue and depression. Presently the most affordable
method of vegetative nervous system functioning
analysis is heart rate variability (HRV) with the
examination using the method of
rhythmocardiography (RCG). Overtraining
manifests by reduced HRV on the rhythmogram
(Bolotin, Bakayev, and You, 2018).
The rhythmocardiography method is currently
being widely used for evaluation of training
effectiveness in athletes practicing various sports
disciplines, and it is difficult to overestimate its role
in assessing adaptation to the conditions of sports
practice and training process management (Bolotin,
Bakayev, and Bochkovskaya, 2018). Nevertheless,
to date virtually no research describes the
peculiarities of heart rate variability in visually
impaired athletes, which complicates the process of
instructional support of their training and assessment
of their current physiological condition.
The purpose of this work is to study the
peculiarities of visually impaired skiers’ adaptation
to training loads in conditions of sports practice.
2 ORGANIZATION AND
METHODS
The research was performed at the Institute of
Physical Culture, Sports and Tourism in Peter the
Great St. Petersburg Polytechnic University. The
study involved 42 skiers. The experimental group
(EG) comprised Paralympians with visual organ
impairment (n=23), whereas the control group (EG)
comprised athletes from the Russian Federation
national cross-country skiing team (n=19).
The research included an examination of the
heart rate variability using Kardiometr-MT computer
analyzer by TOO Mikard Lana at rest, immediately
following the training, and before competition, and
an examination using FirstBeat SPORT computer
system for determining the training effect and
overnight recovery on a daily basis during 7 days of
the training camp.
The analysis was performed on short 5-minute
and long 7-day heart rate variability records of the
athletes taken during the periods of their training
camps and competitions.
The research used the following RCG
parameters, which were found to be most applicable
in sports studies:
RRav. - an average interval between cardiac
cycles in ms;
RRmin and RRmax - minimum and maximum
intervals between cardiac cycles in ms;
dX - variation range - the difference between the
longest and shortest RR intervals (cardiac cycle)
in milliseconds (ms);
SDNN - the standard deviation of the NN
interval from the average value in ms. It is
calculated as a square root of the RR intervals
spread. The SDNN reflects all cyclic components
responsible for variability during the recording
period;
СV (%) (the coefficient of variation) does not
differ from the SDNN in terms of physiology but
is normalized by heart rate;
RMSSD - square root of the mean squared
differences of successive RR intervals in ms.
Mo - mode (ms) - the range of the most
frequently occurring values of cardiac intervals -
the peak of the histogram. It shows the most
likely (dominant) level of functioning of the
Peculiarities of Adaptation to Training Loads in Paralympian Cross-country Skiers with Visual Impairment versus Able-bodied Athletes
based on Analysis of Heart Rate Variability Data
133
sinus node. This is the highest RR interval - peak
of the histogram.
AMo (%) amplitude mode - the percentage of
cardiac intervals that fall into the range of the
mode, in relation to all cardiac intervals. The
mode amplitude depends on the influence of the
sympathetic part of the VNS and reflects the
degree of centralization of the heart rhythm
regulation.
The heart rhythm wave structure analysis was
performed:
TP - total power (area of waves on the RCG) of
the RCG wave spectrum in ms
2
;
HF - fast or high-frequency oscillations of the
RCG wave spectrum reflecting the work of the
parasympathetic nervous system and the
autonomous circuit for regulating the heart
rhythm (frequency range from 0.15 to 0.4 Hz) in
ms
2
;
LF - slow or low-frequency oscillations of the
RCG wave spectrum reflecting the work of the
sympathetic nervous system and the central
rhythm regulation circuit (frequency range from
0.04 to 0.15 Hz) ms
2
;
VLF - very slow or very low-frequency
oscillations of the wave spectrum of the RCG
reflecting the work of the central and humoral
channels of heart rhythm regulation (frequency
range from 0.04 to 0.015 Hz) ms
2
.
Indices according to Baevsky:
VRI (vegetative rhythm index) AMo/Mo dХ.
The smaller the VRI, the higher the activity of
the parasympathetic part and the autonomous
circuit.
RPAI (regulatory processes adequacy indicator)
AMo/Mo to identify the relationship between the
level of functioning of the sinus node and
sympathetic activity. This is the indicator
reflecting the interaction between the
autonomous circuit and the humoral regulation
channel.
SI (regulatory systems strain index) AMo/2dX
Mo reflects the degree of centralization of heart
rhythm regulation.
In the pedagogic experiment, the training was
monitored using FirstBeat SPORT software and
hardware incorporating the dedicated BodyGuard
sensor, which enables recording of the athlete’s
cardio signal for up to 7 days continuously, and
FirstBeat BodyGuard software, by FirstBeat
(Finland).
The research comprised an analysis of the
training process using pulsometry and heart rate
variability, including remote analysis, and
monitoring of recovery after the training load. The
software converted pulsometry and heart rate
variability data into a unique digital model in
accordance with advanced methods of mathematical
data processing, and produced dedicated reports.
The FirstBeat SPORT system
(www.firstbeat.com) is a single-channel
electrocardiograph with large built-in memory
capacity that enables recording a pulsogram
continuously for up to 7 days.
The hardware was used to collect data on heart
rhythm regulation circuit condition in skiers on
round-the-clock basis. Simultaneously the
parameters of the training load and post-load
recovery were measured. Thus the design of the
research enabled presentation of the results in the
graphic and digital form to reflect the quality of
training, daily activity and overnight recovery. The
software calculates and generates a digital model of
a specific individual, which describes the main
physiological processes of the body, such as:
maximum oxygen consumption, energy
consumption, oxygen debt, strain and recovery of
physiological processes.
In athletes who were recovering poorly or
slowly, a decrease in heart rate variability and an
increase in the sympathetic excitation of the
autonomic nervous system were registered upon
awakening. Firstbeat technology enabled
measurement of the so-called “recovery coefficient”.
An increase in this indicator was characteristic of a
better quality of recovery. In contrast, its decline
indicated accumulation of insufficient degree of
recovery in skiers. The data was processed on a
personal computer using Firstbeat SPORT software.
The analysis of the RCG records was performed in
accordance with the International Standard of 1996
and FirstBeat’s recommendations. The statistical
significance of difference between the compared
samples was evaluated using the parametric
Student’s t-test.
3 RESULTS AND DISCUSSION
The results obtained in the course of the experiment
justify a conclusion that the process of adaptation to
training loads in experimental group subjects and
control group subjects differed. The pedagogic
experiment involved 42 skiers of superior
sportsmanship, out of whom 23 were Paralympians
with impaired vision, and 19 were athletes from the
national team of the Russian Federation constituting
the control group.
icSPORTS 2019 - 7th International Conference on Sport Sciences Research and Technology Support
134
Table 1: At-rest rhythmocardiography in two groups of skiers on the first day of the training camp.
Parameters
quartile 1
Median
quartile 3
P-value
EG
CG
CG
EG
CG
Mode Мо, ms
875.1
900.2
1050.1
1100.5
1200.1
>0.05
Mode amplitude АМо, %
33.2
19.1
24.6
44.8
32.5
<0.05
Minimum value RR min., ms
784.3
686.2
772.1
930.5
826.9
>0.05
Maximum value RR max., ms
982.6
1148.5
1352.3
1247.8
1446.1
>0.05
Difference between RR max
and min RR dX, ms
198.6
462.0
580.4
316.5
620.0
<0.05
Coefficient of variation CV, %
4.9
5.4
7.5
6.3
11.4
<0.05
SDNN, ms
48.7
61.0
81.0
64.8
127.5
<0.01
RMSSD, ms
30,5
54.4
77.0
61.2
111.0
0.02
Vegetative rhythm index VRI
(с.u.)
5.1
2.3
2.6
5.9
2.9
<0.01
Regulatory processes adequacy
index RPAI (c.u.)
34,8
21.1
24.9
42.7
27.1
<0.05
Strain index SI (c.u.)
95.8
23.3
47.7
112.8
68.4
0.02
High frequency spectrum HF,
ms
2
468.5
1215.0
2138.8
1504.4
3348.5
>0.05
Low frequency spectrum LF,
ms
2
835.8
863.5
1962.6
2264.1
4506.5
<0.01
Very low frequency spectrum
VLF,ms2
365.9
701.0
1566.1
1416.5
2879.6
0.04
Total power of spectrum ТР,
ms
2
1670.2
2779.5
5,666.7
5,185.0
10,734.1
<0.01
LF/HF (c.u.)
1.8
0.7
0.9
1.5
1.3
>0.05
LF, %
50.0
31.1
34.6
43.7
42.0
>0.05
HF, %
28.1
43.7
37.7
29.0
31.2
>0.05
The HRV analysis was performed using 5-
minute RCG records at rest in the morning on the
first day of the training camp before breakfast in
Paralympians (EG) versus the control group (CG).
Results of the 5-minute rhythmocardiogram
records at rest in the morning on the first day of the
training camp, before breakfast and training, are
shown in Table 1.
As seen from Table 1, at-rest rhythmograms of
visually impaired Paralympian skiers differ from the
rhythmograms of the control group of able-bodied
athletes by many parameters.
A general distribution of parameters corresponds
to the classical distribution of quartile values:
quartile 1 is less than quartile 2; median is less than
quartile 3. These circumstances serve as evidence of
objectiveness and statistical representativeness of the
detected trends.
Variability parameters differed in the groups of
athletes in AМo by 33.5 %.
The mode amplitude value depends on the
influence of the sympathetic part of the VNS; its
growth reflects the degree of centralization of heart
rhythm regulation. Thus, based on АМо data, the
strain of regulatory systems in Paralympians at the
camp was reliably higher (р<0.05) than in the
control group of skiers.
One of the most easily obtained parameters of
heart rate variability dX- the difference between
maximum and minimum RR-intervals on the
electrocardiogram in Paralympians was 55.5 % less
than in the control group (р<0.05).
The median dX value in blind athletes amounted
to 258.0 vs. 580.0 ms in the control group (р<0.05).
The research findings indicate that in ski sports the
dX value closely correlates with the aerobic
capability, whereas MOC (maximum oxygen
consumption) values exceeding 60 ml/min/kg had
reliably higher occurrence in skiers with dX equal to
489.6 ms and more. Thus, based on the data
obtained in this ascertaining experiment,
Paralympians tend to have lower aerobic capabilities
than the subjects in the control group.
Peculiarities of Adaptation to Training Loads in Paralympian Cross-country Skiers with Visual Impairment versus Able-bodied Athletes
based on Analysis of Heart Rate Variability Data
135
Medians of the coefficient of variation (СV)
amounted to 5.7 % in the Paralympians’ group
versus 7.5 % in the control group and differed less
than dX values, however also reliably (р<0.05),
mainly due to quartile 2.
Reliable СV differences were discovered
between low-skilled and high-skilled athletes.
Improved sports skills and, respectively, adaptation
of athletes, correlated to the decrease in the СV
value.
In the Paralympians group, SDNN parameters
were less than in the control group by 44.3 %
(р<0.01), RMSSD – by 45.3 % (р<0.02).
SDNN - the integral parameter for presence of
the heart rhythm wave structure, indicating at the
cumulative effect of impact of both sympathetic and
parasympathetic VNS divisions on the sinus node.
This parameter is being very widely used in sports.
RMSSD - one of the most insightful parameters
for assessment of the athlete’s functional condition
as it reflects both variability and autonomy of the
heart rhythm and correlates to the highest number of
other heart rhythm wave structure characteristics.
Thus, variability of Paralympians at rest
appeared to be reliably lower than in the control
group in absence of statistically reliable difference
by a number of other parameters.
The total power of spectrum (TP) in
Paralympians was 76.5 % lower than in the control
group (3210.6 versus 5666.0 ms
2
, р<0.01) due to the
contribution from all spectral parameters.
Thus, all spectral parameters in Paralympians
appeared to be lower than in the control group, with
reliable difference in the parameters of the central
regulation circuit LF (р<0.01) and VLF (р=0.04).
This can be seen as evidence of lower adaptive
capabilities in Paralympians versus the control
group. Statistically reliable differences between the
groups was also established by all integrated
parameters.
VRI medians amounted to 5.5 in Paralympians
versus 2.6 c.u. in the control group (р<0.01). The
VRI is one of the most insightful integrated
parameters in terms of assessment of aerobic
capabilities of athletes in ski sports.
It is a well-known fact that the best functional
condition in athletes at rest is high autonomy and
variability of functioning, along with reduction of
sympathetic regulation and of centralization of the
function’s regulation. This is achieved by structural
and functional rearrangement of physiological
regulation in athletes under the influence of the
training process. However, as shown above, during
the preparation period of the training cycle,
variability of heart rhythm in Paralympian skiers
with the impaired visual function was reliably lower
in comparison to Olympic athletes, whereas
centralization of physiological functions regulation
was reliably higher.
Apparently, “variability is a property of all
biological processes related to the necessity for the
body to adapt to the changing conditions of the
environment”. It reflects input from regulatory
signals readjusting the cells of the body to maintain
the homeostasis or to adapt the body to new
conditions. Heart rate variability is variability of
time intervals between heart beats, which can reflect
the ability for adaptation both in the present moment
(tolerance to the existing loads) and in prospect
(assessment of adaptation reserve).
4 CONCLUSIONS
The obtained results are indicative of higher “price”
of adaptation to the conditions of sports practice in
Paralympic skiers with visual function impairment
versus able-bodied athletes. The former exhibit a
more pronounced strain of adaptive mechanisms and
physiological regulatory systems at rest.
In athletes with visual deprivation at rest, heart
rate variability parameters appeared to be reliably
lower, whereas the dominant central type of
regulation was encountered four times more often
than in high-skilled skiers with healthy vision. With
the same pulse cost of the training load, there was a
reliably lower functional mobilization of regulatory
systems in response to the load and overnight
recovery degree in Paralympians versus the control
group.
Adaptation of Paralympians with the impaired
visual function to the conditions of sports practice
has certain peculiarities in terms of both regulatory
and psychological aspects that should be considered
during the selection of training programs and
methods of psychological and pedagogical
intervention in sports for the blind.
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based on Analysis of Heart Rate Variability Data
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