PhD Al Khalili Mohaned¹
M.E. Stepanova¹
I.O. Abitaev¹
Master student A.V. Kulyabin^1
1Russian State University of Physical Education, Sport, Youth and Tourism (SCOLIPE), Moscow

Keywords: clay court tennis, competitive performance test rate, action success rate, factor analysis, correlation analysis, efficiency ratio.

Background. Modern tennis elite and sport research communities take persistent efforts to improve the long-term training systems for competitive progress on different surfaces including the traditional clay courts.
Objective of the study was to rate the factors of influence on the competitive accomplishments of the top-twenty ATP men players, with two successive games sampled for analysis.
Methods and structure of the study. We analyzed the match video replays to fix 21 key (strategic) competitive actions (variables) of the top-twenty ATP men singles (n=22) followed by a correlation analysis. We supported the study by analyses of the study reports on the subject [1-3]. Furthermore we selected 15 of the 21 competitive performance test rates for the canonical factor analysis without axial rotation to obtain 8 key factors of influence accounting for almost 100% of the competitive success variation range.
Results and discussion. To produce the 21 key competitive performance test rates, we analyzed 78 games of the top-twenty ATP players (n=22). The competitive performance test rates were classified in our registration cards as follows: total strategic actions grouped by classes (attacks, counterattacks, defenses, serves, equal rallies); wins thereof; and necessary attacks (serves; attacks on the short/ half-court balls etc.). Generally, we fixed the obvious actions net of any interpretations of the players’ goals/ intentions. We excluded the duplicating/ overlapping competitive performance test rates (such as the versatility of the individual toolkits, stability and accuracy of the strikes, etc.); and strived to expand as much as possible the range of significant competitive performance test rates computed using special formulas based on the competitive performance registration data. Having collected the key competitive performance data, we run comparative and factor analyses of the 21 variable competitive performance test rates and 39 action success rates in 78 games. Given in Table 1 hereunder is the competitive performance test rate versus success rate correlation analysis.

Table 1. Competitive performance to action success correlation ratios

Given in Table 2 are the key success rates of the sampled men singles on the clay courts classified by attacks, defenses and counterattacks.

Table 2. Factor analysis of the key competitive performance factors

Given in Table 3 hereunder are the efficiency ratios of the attacks, defenses, counterattacks and equal games. 

Table 3. Key competitive performance test rates: integral factors

We would highlight the following two key criteria for selection of the integrated competitive performance rating factors: coverage and benefits for the competitive performance control purposes. We used these criteria to group the competitive performance test rates, with a special attention to their primary or secondary nature and their meanings. We gave a special priority to the group-specific competitive performance test rates combined to facilitate the individual excellence trainings. Then we analyzed the factors yielded by the factor analysis to find the following (1) prime reasons for wins and losses in every game and (2) factorial weights of the factors with account of their correlations with the game success rates. Thus we drafted mathematical formulas to compute the competitive performance test rates and make decisions on how they should be integrated/ combined.
As a result, we arrived to 7 combined competitive performance test rates with the best coverage and benefits for the competitive performance control purposes since they were found: highly correlated with the game success rates i.e. every action success; covering every possible aspect of the strategic action efficiency; and maximally orthogonal with respect to one another. These combined competitive performance test rates include: 1 integral factor to rate success of whatever strategic action; 5 specific competitive performance test rates indicative of the specific action class success; and 1 supplementary competitive performance test rates that may be applied to analyze non-standard arrays of attacks and defenses in a game.
Conclusion. The study found that virtually 100% of the top-twenty ATP men singles’ competitive performance elements on clay courts may be rated by 8 factors; with 7 factors offering the best coverage and benefits for the competitive performance rating purposes – that may be potentially used for the other surfaces and skill classes. We recommend further studies of the competitive performance factors in the modern elite tennis for the whole range of surfaces, for women groups and different technical/ tactical skill levels.

References

1. Al Khalili M., Korolkov A.N., Kulyabin A.V. Definition and analysis of strategic performance indicators in tennis. Aspirant. 2016.no. 4. pp. 10-15.
2. Barchukova G.V. Building technical and tactical skills in individual team sports (case study of table tennis). Doct. diss... M., 1995. 387 p.
3. Leontiev A.N. Activity. Consciousness. Personality. M.: Smysl; Akademiya publ., 2004. 352 p.
4. Godik M.A., Skorodumova A.P. Integrated control in team sports]. M.: Sovetskiy sport publ., 2010. 33 p.
5. Naumko A.I. Competitive activity of elite tennis players of the world and technique of its assessment. PhD diss. abstr.. М., 1996. 152 p.

Corresponding author: rgufk@list.ru

Abstract
Objective of the study was to determine factors affecting the tennis match scoring run as exemplified by two successive tennis plays on clay courts between the TOP-20 tennis players of the men's ATP rankings.
Methods and structure of research. Based on the analysis of the literature data and observation of the tennis plays on clay courts at the level of TOP-20 men’s ATP rankings, 21 variables (indicators) of strategic actions were identified.
Proceeding from the correlation analysis, out of 21 indicators, 15 ones were singled out as suitable for a factor analysis. They were subjected to a canonical factor analysis without axis rotation. As a result, we got 8 factors explaining almost 100% of variance of the game results.
Results of the study. Almost 100% of the data changes are accounted for 8 factors, which include all the indicators of competitive performance in men's singles on clay courts at the level of TOP-20 ATP rankings. At this level, there are 7 indicators that are the most informative and convenient from the point of view of the competitive process management, as on other surfaces and in other categories.
Conclusion. A further study the factors of competitive activity that affect the outcome of games is required: in women's games, on different surfaces, at different levels; tactical and technical indicators.