Dr.Med. N.P. Petrushkina
PhD, Associate professor O.I. Kolomiets
Pediatrician N.A. Simonova
Ural State University of Physical Culture, Chelyabinsk

Keywords: adolescents, ice hockey players, biological maturation, nervous system, excitability, lability, stability, morbidity, sport injuries.

Introduction. The modern literature data speak to the fact that the efficiency of training and promotion of athletes' health depend on various factors, in many instances, on the specific laws of development at each development stage [3]. When loading is not adequate to young athlete’s physiological capabilities, he/she may have different health deviations, of which the principal ones are sport injuries. According to the statistical data [6, 7], hockey (159 cases) ranks second after rugby (188 cases) in the total number of injuries per 1,000 athletes; and in the number of injuries per 1,000 accidents – it ranks fourth – 3.7 cases after snowboarding and rugby (3.8 cases each) and boxing (5.2 cases). When measuring the injury rate per 1,000 competitions, hockey ranks among the first four most traumatic sports, amounting to 16.3 cases (football - 18.8, wrestling - 26.4, American football - 36.9 cases).

Previously, we determined some peculiarities of morbidity in adolescent hockey players [4] and detected some multidirectional differences in a number of morphofunctional indicators in adolescents with various biological maturation levels [4], which, apparently, could affect not only the indicators of effectiveness of their play activity, but also their injury susceptibility. Awareness of these age peculiarities will help avoid injuries and, consequently, preserve athletes' health.

Objective of the study was to assess the role of psychophysiological peculiarities of adolescents at different levels of biological maturation in injury production when playing ice hockey. 

Methods and structure of the study. We observed 12-13-year-old hockey players with various biological maturation levels: Group 1 – "Mediants" – hockey players with age-appropriate sexual development, Group 2 – "Growth retardants" – hockey players with a biological maturation delay, Group 3 – "Early developers (accelerants)" – hockey players whose developmental age advanced beyond their chronological age. The conformity of the chronological age to the developmental age was determined in an integrated manner [2], taking into account the signs of sexual maturation and the level of anthropometric characteristics (body weight and stature).

Based on the findings of the research conducted at the beginning of the preparatory period, we formed the database on the morphofunctional status of each adolescent hockey player (anthropometry, results of the tests characterizing nervous processes and their features, functional level (FL), functional system stability (FSS), level of functional capabilities (LFC), results of the pedagogical tests characterizing speed qualities, as well as the annual sport injury statistics (injuries that caused excluding from training sessions for 5 days or more, or their simplification).

The relationship between the studied indices of the nervous system and injury susceptibility was determined using the cluster analysis, during which the structure of cumulative indices was analyzed based on the absolute coefficients of correlation between them. The single linkage method makes the similarity matrix noticeable, and gradually, the most similar objects unite into clusters [1].

Results and discussion. The cluster analysis of the available data made it possible to relate anthropometric characteristics, pedagogical test results, injury risk and a number of features of the nervous processes (see Figure 1).

Figure 1. Correlation matrix of multivariate cluster analysis results

Absolute correlation coefficients: М – 0.876 and more, Ш – 0.751-0.875, Х – 0.626-0.750, О – 0.501-0.625, / – 0.500 and less.

As follows from the correlation matrix data, the corresponding levels of body weight and stature created their own clusters. One cluster with the low level of the functional system stability included the CFFF, low and average levels of lability of the nervous processes, prevalence of the excitation processes, injuries, high and low anthropometric indices (early developers and growth retardants), as well as the results of the tests that characterize starting velocity, general speed and ability to switch.

The high level of the functional systems, average anthropometric indices (mediants), time of the SVMR, ability to switch (acceleration/deceleration time and slalom skating) were included in one cluster. The ability to switch, excitation and inhibition balance, high level of lability of the nervous processes, functional system stability and injury risk created a separate cluster, which indicates their correlation.

Due to the high injury risk (the absolute correlation values equaling to 0.65 and more) the following factors were united: high stature, low level of the functional system stability and low level of functional capabilities, high indices of the CFFF, low lability of the nervous processes and prevalence of the excitation processes.

Previously, when evaluating the functional status of the nervous system and morbidity in young ice hockey players, we were able to detect some multidirectional differences in the studied indices of adolescents from the examined groups [4, 5]. The main differences were observed in the group of hockey players, whose developmental age lagged behind their chronological age. Thus, although the mean values of excitation of the nervous system in the examined groups were similar, in the group of growth retardants the functional system stability and the level of functional capabilities were significantly higher compared to the groups of mediants and early developers. There were significantly more children with the average lability of the nervous processes and prevalence of the inhibition processes in the group of growth retardants than in the group of early developers. Owing to the fact that the characteristics of the nervous system are determined genetically and change considerably during puberty due to hormonal influences, the detected peculiarities are quite understandable. The relationships between the studied indices determined during the cluster analysis confirmed the role of puberty changes in injury production in young hockey players.

Conclusion. The study revealed the risk factors for sport injuries among young hockey players and confirmed the need for an individual approach in the organization of the training process with due regard to age peculiarities, which would help not only improve the efficiency of the training process, but also reduce the injury rate.

References

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2. Vozrastnaya fiziologiya (Developmental physiology) / N.P. Petrushkina, E.V. Zhukovskaya. – Chelyabinsk: USUPhC, 2010. – 300 p.
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Corresponding author: 25ppnn@mail.ru

Abstract
Objective of the study was to assess the role of psychophysiological peculiarities of adolescents at different levels of biological maturation in injury production when playing ice hockey. We observed 12-13-year-old hockey players with various biological maturation levels: Group 1 – "Mediants" – hockey players with age-appropriate sexual maturation, Group 2 – "Growth retardants" – hockey players with a biological maturation delay, Group 3 – "Early developers" – hockey players whose developmental age advanced beyond their chronological age.
The study revealed the risk factors for sport injuries among young hockey players and confirmed the need for an individual approach in the organization of the training process with due regard to age peculiarities, which would help not only improve the efficiency of the training process, but also reduce the injury rate.