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14THE INFLUENCE OF COMPETITIVE LOADS ON FUNCTIONAL STATUS OF ARCHERS' CNS
I.N. Buchatskaya, Ph.D.
Velikie Luki State Academy of Physical Culture and Sports, Velikie Luki, Russia
Key words: archers, parameters of simple visual-motor reaction, level of functional status of central nervous system (CNS), special preliminary period, competitive period.
Introduction. Unlike most sports where athletes meet in combat with each other, in archery an archer conducts one of the most difficult fights - a duel with himself, where it is very important to control personal mental condition, show good physical, technical and tactical skills, using his previous competitive experience [5]. Generally, archer's competitive activity is an alternation of the long-term static and dynamic relatively monotonous work being performed for several hours. This is associated with the considerable stress for the nervous system, which should be used to control high accuracy and uniformity of muscular efforts required to maintain the stability of the "archer - weapon - target" system. Every shot during the distance is a kind of "start" for an archer, followed by "finish" in the form of result, and he needs to perform a few dozens of such starts and finishes on each distance. In this regard, archer's fatigue is mostly expressed in mental rather than in physical fatigue, although physical loads are high enough [6]. The specificity of archery consists in the crucial importance of athlete's psychophysiological state.
Hence, the objective of the study was to examine the level of the functional status of the CNS of archers during competitions to validate the need for their psychological training for the competitions. Materials and methods. The functional status of the CNS was estimated by the methodology "Simple visual-motor reaction" (SVMR), based on the findings of T.D. Loskutova [3] and A.M. Zimkina [2] on the hardware and software complex "NS-PsychoTest" ("Neurosoft", 2008, Ivanovo town, Russia). A total of 84 studies involving 12 archers with different sports qualifications (from 1st Class athletes to Masters of Sports) were conducted. All the probands were fully instructed regarding the studies and they gave a written consent to take part in the experiment in compliance with the Declaration of Helsinki. The mean age of the probands was 18,5±0,45 years. During the special preliminary period of the year-round training, the baseline parameter values of SVMR were registered in the probands. During important competitions, each archer was examined six times in accordance with the following outline: the day before the competition, on the 1st, 2nd, 3rd, 4th day of the competition, the day after the competition. The baseline study of the athletes was conducted in a separate laboratory on the basis of the Scientific Research Institute for Sports and Recreational Physical Culture, during the competitive period - 2 hours
before the competition in a separate room only with those individuals who were directly involved into the experiment. It took around 8 minutes to examine each proband.
A psychophysiological tester provided automatic production of 70 red light stimuli at arbitrary points of time, and those were the most intensive stimuli with variation of interstimulus interval within the range of 0.5 - 2.5 sec. The distance set between the eyes and the visual-motor analyzer was 60-80 cm. Data evaluation by the methodology "Simple visual-motor reaction", on condition of its normal distribution, was done relying on the threshold mean values of the key statistical parameters /average response time value and standard deviation/ and additional statistical parameters of the SVMR in healthy probands [4] /Whipple's index, coefficient of variation (CV) and 3 quantitative criteria offered by T.D. Loskutova: nervous system functional level (NSFL), nervous reaction stability (NRS) and level of functional abilities (LFA).
Statistical processing of the data was made on PC Pentium 4 with Windows XP Professional operating system using the program Statistica 10.0. (Statsoft Inc, USA, 2010) by means of Basic Statistics and such non-parametric tests as Wilcoxon matched pairs test, Spearman Rank Order Correlations. Results and discussion. In order to determine different levels of the CNS functional status in the archers, we differentiated the threshold mean values of the standard parameters of the SVMR in the healthy probands, as offered by I.N. Mantrova [4], on condition that automatic production of 70 red light stimuli would be provided. The threshold mean values of the statistical parameters of the SVMR with different normal value levels of the healthy probands are represented in Tables 1 and 2. Basing on the provided data, the analysis of the levels of the CNS functional status of the archers during the special preliminary (baseline study) and the competitive periods was conducted.
Table 1. Standard levels of key statistical parameters by the methodology "Simple visual-motor reaction", ms (visual-motor analyzer)
Indices Color of light stimulus Age Number of light stimuli Normal value levels Binocular study Right eye (dominant)
M (mean reaction time), ms red 17 and more 70 high 193-203 202-220
average 204-213 221-239
low 214-223 240-258
SD (standard deviation), ms red 17 and more 70 high 23-47 31-43
average 48-72 44-56
low 73-97 57-69
Table 2. Standard levels of additional parameters by the methodology "Simple visual-motor reaction",
c.u. (visual-motor analyzer)
Indices Color of light stimulus Age Number of light stimuli Normal value levels Binocular study Right eye (dominant)
NSFL red 17 and more 70 high 4,7-4,9 4,6-4,9
average 4,4-4,6 4,3-4,5
low 4,1-4,3 3,9-4,2
NRS red 17 and more 70 high 2,2-2,5 2,1-2,4
average 1,8-2,1 1,6-2,0
low 1,3-1,7 1,1-1,5
LFA red 17 and more 70 high 3,9-4,2 3,8-4,1
average 3,4-3,8 3,3-3,7
low 3,0-3,3 2,9-3,2
The baseline study showed that the parameters recorded in 83.3% of the archers in case of binocular perception were as follows: mean time of simple sensorimotor reaction characterizing the average level of the CNS functional status, and high stability of the sensorimotor reaction by the standard deviation value (SD), 16.7% - high level of the CNS functional status at average stability of SVMR. 66.7% of the archers were proved to have average, 16.6% - low and 16.7% - high accuracy index of the sensorimotor reaction (Whipple's index). While evaluating the SVMR parameters using the criteria offered by T.D. Loskutova, it was found that 83.3% of the archers had average nervous system functional level (NSFL), 66.7% -average nervous reaction stability (NRS) and average level of functional abilities (LFA); 16.7% - high NSFL, 33.3% - low NRS, 16.7% - low and 16.6% - high LFA. During the monocular study (with dominant right eye), 71.4% of the archers were detected to have high level of the CNS functional status and high nervous reaction stability, 28.6% - low level of the CNS functional status and average stability of the SVMR. In 50% of the probands the baseline sample was characterized by high, in 33.3% - by average and in 16.7% - by low accuracy indices. 66.7% of the archers had high NSFL, average NRS and average LFA; 33.3% - average NSFL and high NSR; 16.6% - low and 16.7% - high LFA. While analyzing the obtained values of the main and additional statistical parameters of the SVMR in every proband by the competition days, it was found that in case of binocular perception 66.7% of the archers had low, 33.3% - average sensorimotor reaction rates; 71.4% of the probands had high nervous reaction stability, 28.6% - average one; 50% - low and 50% - average accuracy indices of the reaction under study; 83.3% - average NSFL, low (below the mean threshold normal value!) LFA and low NRS, and 16.7% - low level of NSFL, average LFA and average NRS. The values of the SVMR parameters in
case of monocular perception stick out: 83.3% of the archers displayed average rate and high stability of the sensorimotor reaction, and 16.7% - low rate and average stability of the sensorimotor reaction. Herewith, 66.7% of the probands were characterized by low accuracy index of the reaction under study, and only 33.3% - by average one. 66.7% were marked by low NRS (below the mean threshold normal value!), low LFA, and 33.3% - by average NRS and average LFA. During competitions, 83.3% of the archers had average, 16.7% - low NSFL. Probably, this decrease in the values of the additional parameters of the SVMR in most of the probands within the monocular study during important competitions, as compared to the baseline level, indicates that there were the CNS fatigue processes due to high competitive loads imposed on the right dominant eye.
Table 3 represents the mean values of the SVMR parameters in the archers during the special preliminary and competitive periods. Thanks to interpreting the obtained quantitative values of the SVMR parameters by Tables 1 and 2 we managed to evaluate the qualitative aspect of the functional status of the CNS and to represent it in Table 4, having indicated the baseline and the competitive levels of the archers' CNS functional status.
Table 3. Mean group indices of SVMR parameters of archers during special preliminary and competitive
periods (n=12, M±SE)
Parameters of SVMR Mean reaction time, ms Standard deviation, ms (SD) NSFL NRS LFA
Baseline (binocular) 207,33±2,31 38,90±1,68 4,43±0,10 2,08±0,06 3,42±0,16
Binocular perception 218,81±3,87* 43,82±2,64* 4,50±0,18 1,77±0,11 * 3,38±0,12
s c (competitions) p=0,00008 p=0,001 p=0,23 p=0,03 p=0,86
o C e a Baseline (monocular
perception - right 218,00±3,73 38,22±1,73 4,62±0,15 1,92±0,14 3,45±0,17
x W eye)
Monocular perception (competitions) 224,70±3,92* p=0,00008 43,75±2,77* p=0,000001 4,41±0,21 * p=0,04 1,56±0,13 * p=0,00002 3,14±0,15 * p=0,0008
Note:* - significance of differences as compared to baseline values (Wilcoxon matched pairs test).
Table 4. Comparative evaluation of changes in basic level offunctional status of CNS of archers during competitive period by interpreted mean group parameters of SVMR (n=12).
Type of perception Examination Reaction rate Criteria offered by T.D. Loskutova
NSFL NRS LFA
Binocular baseline average average (closer to higher threshold value) average average
during important competitions low average (closer to lower threshold value) low lowest
Monocular baseline high high average average
during important competitions average average lowest low
As is seen from Table 3, during the competitive period within both the binocular and the monocular studies, a significant increase was marked in: mean sensorimotor reaction time (by 5.25% and 3.07% accordingly) and standard deviation value (by 11.23% and 14.5% accordingly), consequently, provoking a decrease in the rate and stability of the archers' reaction to the light stimulus, which indicated low lability of the CNS under survey conditions. During the monocular study, the values of all the criteria offered by T.D. Loskutova increased significantly, including: the value of the first "NSFL" criterion, defined by the absolute values of the SVMR time - by 4.55%, the value of the second "NSR" criterion, inversely proportional to the value of reaction time distribution and interpreted as the CNS functional status stability - by 18.75%, and the value of the third "LFA" criterion used to evaluate the probands' ability to form a task-adequate functional system and maintain the corresponding functional status for a long period of time - by 8.99%.
This is definitely indicative of the exclusive standards imposed to the monocular perception stability of the dominant right eye under competitive conditions and, in this view, of the decrease in the level of the brain functional status in general. In case of monocular perception, the values of the additional parameters of the SVMR tended to decrease, except for the "NSR" criterion. Its indices were significantly lower by 14.9% during the competitive period. It is to be emphasized that the given criterion also turned out to be the most sensitive to the variations of the functional status of the CNS (according to the variability index) during the baseline study as well as during the study conducted in the process of the competitions. In terms of the baseline study - CV=33.75% in case of binocular, and 25.05% in case of monocular perception, under competitive conditions - CV=28.27% and 32.78% accordingly. Perhaps, the given
statistical parameter of the SVMR comes as the most informative one while evaluating the current status of the CNS.
The "LFA" criterion distinguished itself by its average sensibility to the variations of the functional status of the CNS. Its variability index in terms of the baseline study was CV=11.7% in case of binocular perception and CV=16.92% in case of monocular one, while during competitions it was 16.37% and 17.23% accordingly. The least sensitive was the "NSFL" criterion. In terms of the baseline study -CV=7.53% in case of binocular perception and 9.44% in case of monocular one, in competitive period -CV=12.03% and 7.57% accordingly. The obtained data of the statistical processing conform with the findings of T.D. Loskutova [3] and P.A. Bayguzhin [1].
Moreover, the conducted correlation analysis (Spearman Rank Order Correlations) of 3 quantitative criteria offered by T.D. Loskutova, characterizing specific aspects of the functional status of the CNS, indicated strong interrelation between them, both in terms of the baseline study and under competitive conditions (p<0,05). In case of binocular perception - between NSFL and LFA (r=0.82 and r=0.94 accordingly), NSFL and NSR (r=0.99 and r=0.75 accordingly), LFA and NSR (r=0.74 and r=0.90 accordingly). In case of monocular one (right eye) - between NSFL and LFA (r=0.99 and r=0.88 accordingly), NSFL and NRS (r=0.94 and r=0.88 accordingly), LFA and NRS (r=0.99 and r=1.00 accordingly). This strong interrelation, especially between the "NRS" and "LFA" criteria, proves their informative value for the evaluation of the functional status of the CNS under survey conditions. Consequently, the data obtained within the competitive period indicate its decrease in case of both binocular and to a great extent monocular perception. According to the findings of T.D. Loskutova [3], the level of the brain functional status and its stability are strongly correlated: the higher its level is, the more stable its status gets.
Conclusion. Summing up, we can conclude that a decrease in the functional status of the CNS of the archers during the competitive period provokes a decrease of its stability, hence the ability to develop the state of readiness for competitive loads also goes down. It should be noticed that the analysis of the educational programs and detailed documentation of the Youth Sports School, where the probands study, testifies that nowadays very little attention is paid to their training. The time provided for studying the theory of psychological training in the learning-training groups of 2-4 years of study was only 1-2 hours. Practical classes were not included in the program at all. The study of lesson plans for the learning-training groups revealed the tasks aimed at improvement of their physical and technical training only. It is fair to assume that the reason for decrease in the level of the CNS functional status of the archers during competitions is the stress of a set of the competitive activity factors affecting the organism, to which the athletes were not prepared psychologically in a proper way.
References
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