PhD, Professor A.A. Grushin¹
Dr.Med. E.R. Yashina²
Dr.Biol., Professor T.F. Abramova^3
1Russian State University of Physical Education, Sports, Youth and Tourism (SCOLIPE), Moscow
²National Medical Research Center of Traumatology and Orthopedics named after N.N. Priorov, Ministry of Health of the Russian Federation, Moscow
³All-Russian Scientific Research Institute of Physical Culture and Sports, Moscow

Keywords: zonetime adaptation, cross-country skiers, functional state, training process completion stage.

Introduction. Zonetime displacement desynchronizes the endogenous and exogenous components in the circadian rhythms within the new zone time, followed by a decrease of the functional state due to different rates of restructuring and desynchronization of the endogenous rhythms of human systems, contributes to the formation of desynchronosis of the CNS functioning, hormonal, autonomic nervous and cardiovascular systems, with the initial activation of physiological reactions caused by the subsequent tension of the mechanisms of adaptation [1-5, 7].

Objective of the study was to allocate informative zonetime adaptation markers of elite athletes in view of the chronobiological, climatic and geographical aspects of the region where the training process completion stage takes place.

Methods and structure of the study. The study was carried out during the completion stage of the pre-season training of elite cross-country skiers for the World Cup series (WCS), under the conditions similar to those of the XXIII Winter Olympics held in 2018. There were 4 groups of cross-country skiers, who flew from Moscow to Seoul by taking a direct 8-hour flight (6-hour jet lag) and arrived in PyeongChang (Republic of Korea) at varying times prior to the competition: 3 groups of athletes (males, distance training group – MD; males, sprint training group - MS; females, distance training group - FD; a total of 14 subjects) - 10 days before the first start of the WCS season; 1 group (males, sprint training group - MS-2, 5 people who reached the destination after the IX and XI World Cup series) - 1 day before the first start. A total of 19 people were examined (mean age - 26.5±3.1 years, sports experience - 16.9±3.1 years, MS, MSIC), all allowed to do sports.

Results and discussion. PyeongChang County (Korea), where the Alpensia ski resort is situated, is located in a mountainous region 180 km from Seoul in Gangwon-do province, the average altitude varies from 700 to 780 m (low-hill terrain), which limits the effects of hypoxia. The climate is monsoon with relatively dry and cold weather. The air temperature varies from -9.3 to 0.2 degrees, humidity - 67%. The leading factor limiting the adaptation processes in this region is desynchronosis due to the 6-hour jet lag.

The complex tests carried out on the first day following the flight showed that the functional state of the cross-country skiers reflected their long-term adaptation to sports-specific physical loads influenced by their gender and niche specialization against the background of incomplete recovery, more pronounced in the MS-2 group that had arrived on the eve of the starts, and in the female group (see Table 1). This trend manifests itself differently in different training groups and, first of all, in the reaction of the cardiovascular and autonomic nervous systems (inadequate response of blood pressure when changing from a lying to a standing position, reduced pulse pressure); blood chemistry values (non-optimal balance of testosterone and cortisol, reduced crude protein and glucose levels, hyperferremia and elevated haematocrit), morphofunctional status (reduced labile body mass components), psychological state (poor sleep quality and low determination for training).

Table 1. The initial level of the functional state in the groups of cross-country skiers

The analysis of changes in the functional state indices reveals the most significant systems and characteristics that ensure adaptation to the training effect of the training process completion stage under the influence of the zonetime factor.

Morphological state is characterized by high stability in the distance training groups of cross-country skiers of both sexes for 10 days in the absence of any significant reactions to participation in the competitions from the 11th to the 12th day of stay. Sprint skiers, on the contrary, demonstrate more reactive labile body mass components, which is expressed in the loss of their muscle mass on days 4-8 with the muscle and fat mass levels optimized in the pre-season days 9-10 after the flight, stable during the competition providing 10-day preliminary adaptation; in case of arrival on the eve of the start - the morphological state is unstable and is characterized by the muscle mass loss.

The analysis of the cardiovascular and autonomic nervous systems in all groups of cross-country skiers shows that the most frequent deviations from the physiological norm in the dynamic response are typical of women (33.8% of cases on average) and male sprint skiers who arrived on the eve of the starts (27.9% on average), less often - of sprint skiers with long-term adaptation (25.0%), most rarely in the distance training groups of cross-country skiers (18.8%). Pulse pressure is the most vulnerable characteristic for all groups, which generally reflects the physiological imbalance between the cardiac function and vascular tone, which is most typical for females in the lying and standing positions (73% of cases) with an initial tendency to hypotension, and for sprint skiers in the standing position (88.9% of cases) who arrived on the eve of the starts. The most unstable days in the groups are: females - the 6th (end of the 1st microcycle) and the 11th (after the 1st start) days (42 and 44% of cases); males - distance - the 10th (1st start) day (33.8% of cases); male sprint skiers - 10th and 11th (1st start and after) days (50 and 45.5%). In general, an unstable response of the autonomic nervous system is observed throughout the entire training process completion stage, which is intensifying in response to sprint competitions with the relatively stable reaction being formed by the 7th-8th days of stay, with the subsequent impact of the training effect and competitive factor.

The blood chemistry values at the training process completion stage primarily revealed the relative stability of the oxygen transport system markers, where the risk factor is the achievement of the highest (close to the upper limit or above the norm) values ​​of haematocrit and iron directly during the competitions for male cross-country skiers, which is more pronounced among sprint skiers, with even greater frequency in the absence of prior acclimatization. All groups of cross-country skiers are characterized by changes in the metabolic markers: a steady increase in the cortisol level (above the norm) against the background of a marked decrease in anabolic activity (free testosterone) from the 6th to the 12th day, which is also most often noted in the absence of prior acclimatization during the competitions. Protein metabolism: a decrease in the crude protein level on the 1st, 2nd (flight, unusual unbalanced diet), 7th, 10th and 12th (competition) days of stay; increased BUN (above the upper limits of the norm) during acute acclimatization and competitions. Carbohydrate metabolism: a decrease in blood glucose during the acute phase of acclimatization in males, after the competitions - in all groups of athletes with a downward tendency in the insular reserves more often in males during the acute phase of acclimatization and during competitions, which increases in the absence of prior acclimatization. Mineral metabolism as a whole varies within the normal limits, critical moments - high levels (above the norm) of calcium and magnesium simultaneously at the moments of competitions in sprint distances. In addition, the majority of athletes are found to have an increased level of aspartate aminotransferase (AST) on the 5th day of acclimatization and during the competitions.

Conclusions. The completion stage of the pre-season with a 6-hour jet lag is recommended to be finalized with the prior acclimatization period taking 7-9 days. The acclimatization completion terms and adaptation markers reactivity rates are largely dependent on the sport discipline, background wellbeing and fitness rates; prime acclimatization and pre-season training design and management quality, intensity of competitive period; and total terms of prior acclimatization stage.

References

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Corresponding author: grushin.aleksandr@mail.ru

Abstract

The study analyzes benefits of the elite cross country skiers’ zonetime adaptation markers applicable in pre-season with jet lags. The study analyzed the elite cross country skiers ‘ (n=19) daily physical debelopment tests; plus the body anthropometric characteristics; autonomous nervous and cardiovascular system functionality tests; and biochemical adaptation markers. The study made it possible to find the highly informative zonetime adaptation markers including pulse pressure; orthostasic blood pressure; free testosterone and cortisol and their ratios; total albumen, urea, magnesium, AST activity, glucose and insulin rates; plus self-rated determination for training. In case of the elite cross country skiers, the list may also include muscular mass, creatinine and calcium rates. The completion stage of the pre-season with a jet lag is recommended to be finalized with the prior acclimatization period taking 7-9 days. The acclimatization completion terms and adaptation markers reactivity rates are largely dependent on the sport discipline, background wellbeing and fitness rates; prime acclimatization and pre-season training design and management quality, intensity of competitive period; and total terms of prior acclimatization stage.