Functional state of team sports athletes in the annual training cycle

. Determination of the dynamics of the functional state of the musculoskeletal system of team sports athletes in the annual training cycle. The achievement of this goal will allow for providing scientifically-based management of training and competitive processes in the annual training cycle and contribute to the normalization of the functional state of the athlete's musculoskeletal system. The authors assessed the functional state of the musculoskeletal system of athletes involved in football, handball, and field hockey, using goniometry, and stabilometry, as well as testing physical abilities, associated with the flexibility of the joints (forward bend from a standing position (on the bench), bridge, transverse and longitudinal (best of 2 possible), splits). Testing was conducted during the annual training cycle, after the competitive period, and at the beginning and at the end of the preparatory period. Assessment of the functional state of the musculoskeletal system of athletes at the end of the competition period showed the low and below average flexibility levels. Static support ability (stabilometry) and joint mobility (goniometry) were below average and average levels. Decrease in static support ability testified to violations of the vestibular apparatus and proprioceptive sensitivity, which have a significant impact on balance. The low results of joint flexibility and mobility indicated the lack of elasticity of the musculoskeletal apparatus, which indicated the presence of overstrain. Diagnosed positive changes in the state of the musculoskeletal system of athletes at the beginning and at the end of the preparatory period, regardless of the team sport, indicated a partial restoration of the functional state of the musculoskeletal system during the transition period. According to the results of the study, recommendations were given for including in the training process, along with prestretching, corrective and preventive exercises based on the use of the myofascial relaxation technique, which contribute to the restoration of the functional state of the musculoskeletal system of team sports athletes.


Introduction
Team sports games in the system of Olympic and professional sports are particularly popular.The analysis of high-level competitions indicates that team sports games are turning into a powerful industry that gathers tens of thousands of fans at stadiums and multi-million viewers (Shakirov and Zhuiko 2021), which, in turn, significantly increases competition in sports and the entertainment quality of competitions (Glebova and Desboard, 2020;Gostian Ropotin et al. 2022).In recent years, there has been a tendency to increase the popularity of sports games and, to a greater extent, team game sports (Fomicheva et al., 2021;Rao et al., 2023).Such popularity of team sports games requires updating knowledge in the theory and methodology of training athletes and doing modern research, considering the trends inherent in sports of the 21st century and sports games in particular (Banciu, Popirlan, & Cosma, 2021;Saenz Lopez et al. 2023).
The reflection of modern trends in the system of athletes' training in team sports games has been the object of research of the last decade, where the researchers scientifically substantiated the solution to such problems as the management of athletes' training (Fedotova 2007;Shamardin 2006: Tyulenkov 2007); evaluation, modeling, and forecasting of team results (Golubev, Shchedrina 2020;Ballesteros, Peñas 2010); sports selection and orientation (Popovich et al. 2020;Jordanskaya 2008); structure and content of the training process at various stages of long-term training (Fedotova 2001;Aleshin, Rybakov 2007;Ignatieva et al. 2005); management of technical and tactical activities (Zheleznyak et al. 2004;Fedotova 2004); the use of information technologies in the preparation of athletes playing game sports (Tryapichnikov 2020;Rusmanto et al. 2023), etc. Scientific research and competitive practice show that the greatest success is achieved by teams that, firstly, have a modern material and technical base and financial support, secondly, which include high-class athletes, and thirdly, carry out their activities based on scientifically sound management of training and competitive processes (Vovk 2007).
The main tendency of modern sports is to increase the intensity of training and competitive activity of athletes (Popovich et al. 2016;Vila Suarez et al. 2023).Therefore, against the background of an increase in the volume of training work, an operational assessment of the functional state of the main physiological systems supporting the body's performance (musculoskeletal (Shahzad, Zulfiqar, & Ali, 2022;Guillen Pereira et al. 2023), cardio-respiratory (Pla Pla et al. 2022), etc.), becomes important (Morozova, 2014).Accordingly, research aimed at finding and developing new highly informative methods for assessing the functional state of athletes and introducing team sports into practice is of particular importance (Vilar et al. 2013).
Human health presupposes a sufficiently high level of physical fitness, physical development, and working capacity (Colangelo et al., 2023), which causes the problem of finding physical activities adequate to the physical condition of the individual (Navarro & Safar, 2020).This problem, first of all, is faced by coaches, whose goal, on the one hand, is to contribute to the achievement of high athletic results for their students, and on the other hand, to preserve and improve the functional state of the athletes' body without mobilizing their reserve capabilities (Witvrouw et al. 2003).
From many studies that relate to the modern problems of functional training of athletes, it is known that elite sport is characterized by a sharp increase in the volume and intensity of training loads, the high psycho-emotional intensity of training, and competitive processes (Stukova et al., 2023;Schumann, Wojciechowski and Bunn, 2023).These circumstances lead to increased demands on the functional state of athletes, a potential decrease in functional abilities, performance, an increase in fatigue, and sometimes to maladaptation and overwork (Sassi and Tibaudi, 2007).
The creation of effective means and methods for restoring the health of athletes after loads in the training and competitive periods, often reaching a critical value, is a significant task for modern sports training (Chan et al., 2012).In this connection, the development of an optimal system for restoring the entire body of an athlete in a complex, aimed at increasing the level of its functional state, helps to maintain working capacity at a high level and prevents the negative consequences of overwork and overstrain (Komarov et al. 2013).
At the same time, studies have noted an increase in micro-traumatism in team sports due to chronic overwork and overstrain of the musculoskeletal system (hereinafter called MSS) (Jerez Mayorga & Villaquiran Hurtado, 2023), especially in game sports (Stojanovic and Ostojic, 2011).
Constant physical overload and the associated overstrain of the MSS lead to an increase in the likelihood of injury to the athlete and subsequent diseases of the MSS, which own a significant proportion of the pathological conditions of athletes, which makes it impossible for them to complete training and participate in competitions for a long period (Jordanskaya and Yudintseva, 2006).
Thus, directly dependent on the functional state of the MSS, the flexibility of athletes with overstrain tends to significantly decrease, which leads to the development under conditions of overstrain can significantly decrease, which is why this phenomenon leads to the development of muscle imbalance (Korzun, 2012).
Henceforth, the development of efficient means and methodologies aimed at restoring athletes' health during both training and competitive periods, along with the optimal restoration system of the entire body, constitute pressing tasks in contemporary sports training.
Regarding team sports, regular monitoring of the musculoskeletal functional state, coupled with timely overstrain prevention, presents an opportunity to adjust the training process of individual athletes and the team as a whole.Consequently, it may aid in averting injuries to athletes while promoting individual and team success.
Against this backdrop, this study aims to determine the dynamics of the musculoskeletal functional state of athletes partaking in team sports within the annual training cycle.

Study design
The study was conducted among athletes playing football, handball, and field hockey in integrated sports schools in the Moscow region, Russia.
During the annual training cycle, three tests were supposed to be conducted: after the competition period (September 2021) and at the beginning and end of the preparatory period (February and May 2022, respectively).

Study sample
The study involved 122 athletes aged 16-17 years, of which: the first group (46 people) were male teenagers who had been playing football for a long time; the second group -108-Retos, número 54, 2024 (marzo) (39 people) were male teenagers who had been playing handball for a long time and the third group (37 people) were male teenagers who had been playing field hockey for a long time.

Materials and methods
We used the following methods: the study and analysis of scientific and methodological literature, pedagogical observations, assessment of the functional state, and statistical processing of study results.We studied (with subsequent analysis) scientific and methodological literature on changes in the functional state of athletes at various stages of the annual training cycle.
The evaluation of the musculoskeletal system's functional state was conducted using goniometry, stabilometry, and physical ability tests, which included assessments of joint flexibility.
In the current study, motor tests (Jordanskaya, Yudintseva 2006; Korzun 2012) were used to assess the mobility of the joints of the lower extremities and spine.Several simple tests were selected, such as leaning forward from a standing position (on a bench), gymnastic bridge, cross split, and forward/backward splits (the best of 2 possible).
Stabilometric indicators, such as the total length of the stabilometry path (L, mm) and the area of the statokinesiogram (S, mm2) with eyes open, were evaluated.The development level of these parameters was determined based on the arithmetic mean value of the group.For each of the considered parameters, the level of its development was determined according to the average group value with the determination of the arithmetic mean and deviation from the arithmetic mean (M ± σ).
During the measurement, the ST-150 stabilometric platform with a laptop was used.The platform itself is directly connected to the USB port of the computer, from which it is also powered.
Goniometry was used to measure the mobility (flexion, extension, abduction) of the hip, knee, and ankle joints in angular values (degrees).
An iGaging electronic goniometer was used for the measurement.Three measurements of the same movement were carried out, and the maximum indicators were recorded.

Processing of results
Mathematical processing of the results of the study was carried out using the SPSS Statistics software, and it allowed us to determine the arithmetic mean values of independent distributions (M) and the standard deviation from the arithmetic mean of the attribute (σ).

Results and Discussion
The initial assessment of the musculoskeletal system's functional state was conducted as scheduled at the conclusion of the competitive period (September 2021).The findings revealed that most of the flexibility indicators were below the average level, with only the "Forward bend from a standing position" test yielding an average performance level (Table 1).Stabilometric measurements conducted at the end of the competitive period revealed that nearly half of the athletes diagnosed with team sports had a static support ability below the average level.Additionally, approximately 60% of the athletes demonstrated insufficient vertical posture stability, indicating a decline in balance ability.Furthermore, a significant number of subjects demonstrated low displacement of the common center of mass's rear projection in the frontal (22%) and sagittal (46%) planes.Notably, 64% of the subjects exhibited statokinesiogram areas corresponding to average and below-average levels, with less than 36% having lengths corresponding to average levels.
Analysis of the goniometry data of the joints of the lower extremities of the subjects revealed that the indicators of joint mobility in athletes were also within the average and below average levels (Table 2).The planned measurement of the functional state of the MSS carried out at the beginning of the preparatory period (February 2022), allowed us to establish the presence of positive changes in the examined athletes, regardless of their engagement in a certain type of sport (see Table 3).According to the results of stabilometry conducted at the beginning of the preparatory period of the annual macrocycle, more than 85% of the studied football players, handball players, and hockey players had an above-average level in terms of static supportability.
Besides, for indicators of stability of the vertical posture, more than 75% had an above-average level, which indicates an improvement in the balance function.
Displacement of the common center of mass's rear projection in the frontal and sagittal planes was higher than the typical indicators for the average level in over 70% of the examined athletes.Furthermore, the area of the statokinesiogram corresponded to average and above-average levels in over 90% of the subjects, with the average length of the statokinesiogram noted to be above average in more than 66% of the players.A comparative analysis of flexibility and stabilometry test results at the end of the competition period and the beginning of the preparatory period indicated significant differences in all indicators (Table 3).The analysis of goniometry results revealed that the indices of lower extremity joint mobility in athletes were also within average and above-average levels (Table 4).Athletes at the end of the competition and the beginning of the preparatory period of the annual macrocycle showed significant differences in all indicators (Table 4).The last (third) routine testing in the annual training cycle of team sports athletes was conducted at the end of the preparatory period (May 2022) and allowed to establish the presence of both positive and negative minor changes in the examined athletes (Table 5) --Notes: r: right joint; l: left joint; a: average; b/a: below average; a/a: above average; *: the probability of statistical differences with the previous stage, p < 0.05; the lack of data on several indicators is explained by the impossibility of obtaining them from the initial position when measured due to the physiological features of the structure of the joints of the lower extremities of the human body Statistical analysis did not show significant differences in the performance of flexibility tests and stabilometry of athletes at the beginning and the end of the preparatory period of the annual macrocycle.Analysis of the goniometry data of the joints of the lower extremities of the subjects demonstrated that the indicators of joint mobility in athletes were still within the average and above average levels (Table 6).Statistical analysis showed no significant differences in the goniometry of athletes at the beginning and the end of the preparatory period of the annual macrocycle.
The low scores in stabilometry, goniometry, and flexibility tests of team sports athletes at the end of the competitive period may be attributed to natural fatigue and associated reductions in both physical and functional readiness.Our opinion is supported by findings from previous studies on the subject (Sassi et al., 2013).The improvement of the test results for the indicators of joint flexibility, stabilometry, and goniometry at the beginning and the end of the preparatory period of the annual macrocycle is because the functional state of the MSS was restored during the transition period of the annual macrocycle.However, some researchers believe that to restore joint flexibility indicators, it is mandatory to use specially developed recovery techniques (Maestroni et al., 2020).The generalization of the obtained results and their comparison with the data of previous studies necessitated the search for a solution to the problem of the development of joint flexibility for athletes engaged in team sports and the restoration of the state of their MSS.Thus, according to some researchers, this can be facilitated by the use of innovative techniques of myofascial relaxation (Witvrouw et al., 2003), firstly, as a means of muscle stretching and secondly, for recovery after high physical exertion to prevent injuries of the MSS, due to insufficient elasticity of the myofascial structures of the athletes' body.
It is worth noting that an appropriate selection of sports rehabilitation methods following significant physical exertion may elevate the musculoskeletal system's functional state indicators to higher levels and maintain them for prolonged durations during the subsequent competitive period (Vilar et al., 2013), and thus to contribute to a high final result of the athletes' work at competitions.Some researchers suggest that the use of yoga exercises in the educational and training process of athletes playing game sports also has a positive effect on the functional state of the MSS and thereby contributes to the correction and prevention of chronic overstrain and injuries (Abaïdia and Dupont, 2018;Schumann, Wojciechowski and Bunn, 2023).With a decrease in the range of motion in individual joints in the pelvis and lower extremities in athletes playing game sports, researchers suggest the use of both static and dynamic stretching, the use of which showed a significant increase in hip flexion indicators (Mahrová et al., 2014).The program with static stretching alone showed a significant improvement in ankle flexion indicators (Thompson and Rogerson, 2020).Thus, a stretching program can lead to an increase in the range of motion in some joints after a special program.

Conclusion
The low level of the musculoskeletal system's functional state of athletes at the end of the competitive period, as indicated by the results of stabilometry, goniometry, and joint flexibility tests, implies poor ligamentous apparatus elasticity.This is one of the signs of chronic musculoskeletal system overstrain, which could lead to decreased work capacity.Insufficient recovery and increased physical and mental overload may increase the likelihood of injuries and subsequent illnesses.
After the competition period, there was a decrease in the stabilometric indicators in general and, in particular, the values of indicators characterizing the stability of the vertical posture.This fact may indicate individual disorders of the MSS, instability of the joints of the lower extremities, or the presence of vestibular and proprioceptive disorders.
The measurement of the functional state of the MSS carried out at the beginning and at the end of the preparatory period made it possible to establish the presence of positive changes in the examined athletes, regardless of their doing a certain type of sport.This fact may indicate a partial restoration of the functional state of the MSS during the transition period of the annual macrocycle.
In addition to the usual preliminary stretching (prestretching), the athletes were recommended to include corrective and preventive exercises using the technique of myofascial relaxation (MFR) in the training process, which will contribute to the normalization of the functional state of the MSS and reduce the risk of injury.
The limitations of the study include the lack of variability of the studied sample of athletes by age and the lack of consideration of age-related features of the dynamics of the functional state of the MSS of athletes playing team sports in the annual training cycle.
The prospect of further studies may be the search for a solution to the problem of the development of joint flexibility of athletes in team sports and the restoration of their MSS through the development of individual components of personal programs and a group (team) model of rehabilitation measures.

Table 1 .
Indicators of flexibility and stabilometry tests performed on athletes at the end of the competition period of the annual macrocycle (M ± σ)

Table 2 .
Results of goniometry in athletes at the end of the competition period of the annual macrocycle, (M ± σ, degrees) lack of data on several indicators is explained by the impossibility of obtaining them from the initial position when measuring due to the physiological features of the structure of the joints of the lower extremities of the human body 2024, Retos, 54, 106-113 © Copyright: Federación Española de Asociaciones de Docentes de Educación Física (FEADEF)ISSN: Edición impresa: 1579-1726.Edición Web: 1988-2041 (https://recyt.fecyt.es/index.php/retos/index) r: right joint; l: left joint; a: average; b/a: below average; a/a: above average; the -109-Retos, número 54, 2024 (marzo)

Table 3 .
Indicators of flexibility and stabilometry tests performed on athletes at the beginning of the preparatory period of the annual macrocycle (M ± σ)

Table 4 .
Indicators of goniometry in athletes at the beginning of the preparatory period of the annual macrocycle (M ± σ, deg.)

Table 5 .
Indicators of flexibility and stabilometry tests of athletes at the end of the preparatory period of the annual macrocycle (M ± σ)

Table 6 .
Results of goniometry tests in athletes at the end of the preparatory period of the annual macrocycle (M ± σ, degrees) : right joint; l: left joint; a: average; b/a: below average; a/a: above average; the lack of data on several indicators is explained by the impossibility of obtaining them from the initial position when measuring due to the physiological features of the structure of the joints of the lower extremities of the human body