Dr.Hab., Professor A.P. Skorodumova¹
I.S. Baranov¹
S.D. Semenova¹
PhD Ya.V. Golub^2
1Federal Science Center for Physical Culture and Sport (FRS VNIIIFK), Moscow
²St. Petersburg Scientific Research Institute of Physical Culture, St. Petersburg

Keywords: female tennis players, factor analysis, structure of physical and functional fitness, top sports mastery stage.

Background. The analysis of the specifics of the competitive activity of both male and female tennis player was carried out at home and abroad. There is currently no consensus on the requirements for the physical and functional fitness of female tennis players participating in competitions [7, 5, 8, 3, 2].
A survey was conducted among the leading Russian tennis players and coaches, which indicated that most of them put the speed and speed-strength abilities at the center. The same opinion is held by ITF experts [6].
The majority of the world's top players and coaches of the past and present pay considerable attention to breathing, putting it first at other times.
We assume that those experts, who emphasize the importance of correct (regular) breathing during a match, are mistaken about one thing. They reduce the whole problem of energy supply in the playing activity to regular breathing, losing sight of the importance of the development of the athletes' functional capabilities [3].
In the opinion of R. Schonborn, one of the leading ITF specialists [8], the importance of the main physical qualities of tennis players can be assessed in the following manner: coordination - 90%, acceleration rate and speed of coordination - 80%, reaction rate - 70%, muscle strength or elasticity - 60%; speed, speed endurance, aerobic endurance - 55% each, strength endurance, anaerobic endurance and joint mobility - 50%. The terms used by R. Schonborn, such as the speed of coordination, differ from those adopted in the domestic theory and methodology of physical education. The author gives no explanation of the terms used. The official ITF (ITF) textbook confirms the opinion of Ferrautiet et al [1] that aerobic endurance and anaerobic endurance are considered the second most important physical qualities after speed and agility. The peculiarities of the female tennis players' competitive activity, and in particular the external competitive load parameters established so far, give reason to doubt such ranking of qualities [4]. It is important to determine the significance of each quality for the athletic training process planning, selection of the necessary means and, above all, methods of training, which will ultimately be reflected in the competitive performance.
Objective of the study was to identify the structure of physical and functional fitness of female tennis players at the stage of top sports mastery.
Methods and structure of the study. Sampled for the study were 20 top-ranked female tennis players from Russia, aged 17 and older, at the stage of top sports mastery, including winners of the major international tournaments, the Grand Slam among them. For the purposes of the study the following methods were applied: theoretical analysis and generalization of scientific and methodological literature, exploration of coaches' opinions by interviewing the leading specialists, pedagogical observation. The athletes’ physical and functional fitness levels were determined by analyzing the following indicators: aerobic and anaerobic alactic capacity and power, effectiveness of aerobic and anaerobic alactic abilities, the main forms of speed manifestation (reaction rate, speed of a single movement, acceleration rate, rate of movement), speed-strength abilities of the muscles of the shoulder girdle and lower limb muscles when performing movements in different directions, coordination abilities (differentiation of muscular efforts, accuracy of spatial characteristics of movement, speed of movement change), flexibility (overall mobility and shoulder joint mobility) and types of endurance (alactic, lactic, speed-strength). A total of 61 indicators were analyzed.
Results and discussion. The factor analysis of the test results revealed 6 leading factors, accounting for 91.3% of the total sample variance (see Table 1).

Table 1. Factor structure of physical and functional fitness of female athletes at top sports mastery stage.

The first and the leading factor included the indicators, five of which with the high factor loads. Three indicators characterize the aerobic capacity (MBV, MOC and OP), one - the aerobic performance (AnT) and one - the anaerobic alactic performance - the retention time of the maximum effort (ty). This factor is interpreted as a functional capacity factor.
Factor II combined three indicators with the high factor loads: two characterizing the total body sizes (body weight and length rates) and coordination abilities (differentiation of muscle efforts). We interpret it as a factor of total body sizes taken with the manifestation of coordination abilities.
Factor III included two indicators with the high factor loads: oxygen consumption at the level of aerobic threshold and spatial accuracy of movements - "ball sense". This factor is interpreted as a combination of specific coordination abilities and aerobic performance.
Factor IV combined three indicators characterizing the speed and speed-strength abilities of the female tennis players: time of a single movement and standing long jump, and one referring to the total body sizes - body mass index. This factor is interpreted as a combination of the speed and speed-strength abilities and body weight and length rates.
Factor V combined three factors with the high factor loads: the run time in a simple motor reaction, speed of movement, and maximum momentary power. All three indicators describe the speed abilities, so we interpret it as a factor of speed abilities.
Factor VI included three factors with the high factor loads: the jump height in a simple and complex motor reaction, and the shoulder joint mobility. We interpret it as a factor of speed-strength abilities when moving upwards and shoulder joint mobility.
Conclusion. We identified 6 factors characterizing the physical and functional fitness of female tennis players at the top sports mastery stage. The major contributor is the factor that includes their aerobic and anaerobic alactic performance. The anaerobic alactic performance ensures a serve to start the point, the duration of which is up to 10 sec. There are 80% of such serves during a match on the average: 86.12% on the fast and 79.17% on the low court surfaces. Statistics indicate that, during the match, top-ranked female tennis players score on the average 128.13 points on the fast surface and 128.82 points on the slow one. This means that ATP used in the previous rally must be restored to start the next one. Consequently, the aerobic abilities need to be powerful and efficient enough so that in 20 sec allotted for a rest break between the rallies to resynthesize ATP. This will enable to score each point without reducing the necessary indicators - reaction rate and speed of a single movement, movement accuracy, jump height, acceleration rate, etc. Of course, high requirements are set to the speed abilities of female tennis players, as these abilities greatly affect each rally. But at the top sports mastery stage, there is a shift in emphasis. At this stage, there are no female tennis players with insufficiently developed speed abilities. At this stage, it is the possibility to maintain their manifestations for a long time - for more than 2 and sometimes 3 hours - that plays a decisive role. Thus, the requirements for the aerobic performance are raised.
Given the results obtained, the training plans should be reconsidered. Most coaches continue working extensively on improving the athletes' speed abilities, which is a challenge for female athletes at this stage of the multi-year training. There is a need to correct the allocation of time to improve each physical quality at the macrocyclic stages and to clarify the training methods used to improve them.

References
1. Crespo M., Miley D. Textbook of the Best Trainer. ITF Ltd. Bank Lane, Roehampton, London, 1998. 296 p.
2. Savi Fr. Breathing skill: Tennis. Moscow: Fizkultura i sport publ, 1966. 46 p.
3. Skorodumova A.P., Trukhachev A.A., Kuznetsova O.V., Baranov I.S. Tests to assess the physical and functional fitness of tennis players and model characteristics of fitness. Moscow: FSSRT publ., 2013. 40 p.
4. Skorodumova A.P., Golovachev A.I., Eroshkina S.B. et al. Development of model characteristics of physical and functional fitness indices of elite tennis players. Moscow, 2018. 65 p.: Bibliogr.: pp. 33-35, 59-61. Dip. v MinSportRF 30.09.18, no. 118051190099.
5. Ralston D., Flink S., Freeman B. Dennis Ralston’s tennis workbook  1987 by prentice-Hall. Inc. Englewood Cliffs, no.9  p.1-32
6. Reid М., Qiunn A., Crespo M. Physical fitness in tennis. ITF Ltd. Bank Lane, Roehampton, London, 2003.  165 p.
7. Roetert P. Fitness and testing. Coaches review.  I T F, 1994.  p. 4-6.
8. Schonborn R. Energy systems in tennis. ITF Ltd. Bank Lane, Roehampton, London, 1987. 30 p.

Corresponding author: rudra54@yandex.ru

Abstract
Objective of the study was to identify the structure of physical and functional fitness of female tennis players at the stage of top sports mastery. Sampled for the study were 20 top ranked female tennis players from Russia, aged 17 and older, at the top sports mastery stage. The athletes’ physical and functional fitness levels were determined by analyzing the following indicators: aerobic and anaerobic alactic capacity and power, effectiveness of aerobic and anaerobic alactic abilities, the main forms of speed manifestation, speed-strength abilities of the muscles of the shoulder girdle and lower limb muscles when performing movements in different directions, coordination abilities, flexibility and types of endurance. Based on the test results, a factor analysis was conducted to determine the most significant factors and hierarchy of physical and functional abilities in the structure of physical fitness of elite female tennis players. The factor analysis revealed 6 leading factors, the most important of which are aerobic working capacity rates. The authors conclude that the findings can be used in the athletic training process design at the stages of sports excellence and top sports mastery, during lectures at physical education universities for students and coaches undergoing advanced training, when writing qualifying works.