Analysis of technical statistical indexes of college tennis players under the win-lose regression function equation

When athletes carry out special physical training, they should first make a scientific diagnosis of their own special physical level, then understand the level of their own special physical level, and distinguish their own advantages and disadvantages. If we only rely on the self perception of athletes and the experience perception of coaches to judge, it is easy to form a certain deviation from the actual situation, which makes it difficult for athletes to clearly understand their own advantages and disadvantages, so as to induce athletes to practice in the wrong direction, which not only wastes precious training time, but also may lead to the stagnation of their own special physical fitness level and technical level [1]. The formation of special physical fitness evaluation index system has objectivity and authenticity. The special physical fitness evaluation standards involved can objectively and effectively diagnose the unilateral and overall reality of athletes' special physical fitness level, and help coaches carry out targeted special physical fitness training activities. At the same time, it can also make athletes clearly aware of what aspects of training they should strengthen, and avoid training deviation caused by subjective judgment, which ensures the scientific rationality of diagnosis. By consulting the relevant literature in China, we know that many traditional sports in China have formed a relatively complete set of scientific research system for athletes' special physical fitness evaluation. These studies have laid a solid theoretical foundation for the improvement of athletes' special physical fitness level and their technical and tactical level. Chen Z and others believe that for tennis events, at present, there are relatively few scholars involved in the research on the special physical fitness evaluation index system of high-level tennis players in Colleges and universities. Therefore, in order to improve the current situation, it is necessary to study the construction of the special physical fitness evaluation index system of high-level tennis players in Colleges and universities [2]. After consulting relevant literature and actual visit and investigation, it is found that a university is affected by the climate, coupled with relatively backward economic development, lack of venues, weak tennis teachers, unreasonable curriculum and coaches' neglect of athletes' “special physical fitness” training. It not only makes the development level of tennis form a certain gap with colleges and universities in economically developed areas, but also affects some high-level tennis players. After entering the school, their professional and technical level has not been greatly improved, and their special physical fitness level has decreased slightly, which restricts the improvement of their tennis competitive level to a certain extent. Therefore, by constructing the special physical fitness evaluation index system of high-level tennis players in an ordinary university, in order to provide a theoretical basis for their special physical fitness training and effectively promote the improvement of their special physical fitness level. Aswal D and others found that at present, there is a relative lack of systematic research on the evaluation index system of special physical fitness of tennis players by Chinese scholars, especially the relevant research based on the level of high-level tennis players in an ordinary university. Therefore, this study attempts to build a scientific and reasonable special physical fitness evaluation index system for high-level tennis players in Colleges and Universities Affiliated to Heilongjiang Province through in-depth understanding of the characteristics of tennis events, in order to provide a theoretical basis for effectively improving the scientific physical fitness training of athletes [3]. Through the research on the construction of special physical fitness evaluation index system for high-level tennis players in an ordinary university, it can promote the improvement of relevant research to a certain extent, enrich relevant databases, and provide a certain scientific basis for the selection, special physical fitness training and evaluation of high-level tennis players in other universities. At the same time, it can also provide theoretical reference for other researchers to study the special physical fitness evaluation index system of athletes in the same group. By constructing the special physical fitness evaluation index system of high-level tennis players in an ordinary university, firstly, according to the evaluation index model, it is convenient for coaches to select special materials and carry out special physical fitness training activities. Secondly, the evaluation index weight model constructed by Zhang R and others is convenient for athletes to grasp the importance of special physical fitness evaluation indexes at all levels and focus on it in training [4]. Moreover, the use of the constructed single index and comprehensive evaluation criteria is convenient for athletes to scientifically and objectively diagnose their own special physical fitness training level, make qualitative and quantitative evaluation of their own special physical fitness level, and explore their own advantages and disadvantages. At the same time, it is also convenient for coaches to monitor athletes in different training stages in real time in special physical training activities, formulate targeted training plans, and promote the improvement of athletes' own special physical fitness level and the quality of sports team construction.

Taking some college tennis players in a university as the research object. 28 male athletes and 12 female athletes were selected. As shown in Table 1.

Through computer and manual access to a large number of literature on physical fitness, special physical fitness, competition load, tennis physical fitness and tennis competition load characteristics. Through the electronic reading room of Suzhou University Library, I consulted relevant papers and professional works such as sports training, structural characteristics and basic training methods of athletes' competitive ability, physical and psychological training manual of tennis players, sports physiology and rapid strength of sports nutrition [5]. More than 130 papers on the research of ball physical fitness and competition load characteristics in recent years were consulted in the literature libraries such as China HowNet, Chongqing VIP and Wanfang Data Resource System. Combined with the research of other related sports in special physical fitness and competition load, the special physical fitness and competition load characteristics of College Tennis players in a province were systematically analyzed and studied.

Carry out calibration and other test operations according to the instrument instructions. In order to ensure the reliability of the test, calibrate every 5 samples. Through the experiment, a series of indexes about tennis special physical fitness and competition load are obtained. Through questionnaires, expert interviews and other specific methods, combined with the processing of relevant data, this paper determines the evaluation indexes or parameters of special physical fitness and competition load of college tennis players in a university. Under the careful guidance and help of the tutor, the opinions of experts and scholars were widely solicited. In order to ensure the objectivity, authenticity and effectiveness of the questionnaire, the expert evaluation method is used to test the content validity and structural validity of the questionnaire. After the first draft of the questionnaire is completed, the opinions of the tutor are consulted and revised repeatedly, and then the opinions of experts are consulted to form a more reasonable questionnaire. Finally, 10 experts were invited to test the validity of the two questionnaires. 90% of the experts thought that the content and structure design of the questionnaire were very reasonable and 10% thought it was more reasonable (see Table 2), indicating that the questionnaire has high validity.

Sort out and summarize the contents of the video and the contents obtained from the questionnaire survey, then make statistical analysis and classification of the relevant data (SPSS13.0), and make charts or tables, and finally make statistical analysis of the characteristics of athletes' special physical fitness and competition load and their evaluation indicators or parameters.

Combined with the relevant research results, we define the physical fitness as follows: the physical fitness of athletes refers to the sum of the physical exercise ability possessed by athletes themselves and acquired through exercise. It is composed of physical fitness, physical function and body shape comprehensively applied in training and competition. Through the analysis, definition and summary of relevant concepts and theoretical knowledge, as well as the analysis and summary of the concept of special physical fitness by relevant experts, the special physical fitness of athletes is defined as: the subjective ability of athletes to participate in training and competition acquired by the day after tomorrow under the constraints of sports characteristics and competition needs. It is the athlete's body shape, organ function, sports quality and the ability of special training and competition after interacting with the technical, tactical and psychological level. From a systematic point of view, athletes' physical fitness is a complete system composed of multi factors and multi-level structure. Hierarchy is a basic feature of the system. The hierarchy of the system is because there are various differences in the elements of the system, including the differences in the combination mode. Therefore, the elements (or groups of elements) of the system are hierarchical and procedural in terms of status, function, structure and function, showing different system levels or hierarchical differences in the system with qualitative differences [7]. The overall control of this system is the core of the training work. However, in order to achieve the scientific and accurate control of such a developing and changing dynamic whole, it is inseparable from the in-depth investigation and analysis of the constituent elements of the system itself, the embodiment of the internal structure and function of the system. Without in-depth and detailed analysis, it is difficult to form a thorough understanding of the essential law of the physical training system. Therefore, using the system structure theory to scientifically analyze and evaluate the level of athletes' physical structure has important theoretical value. From the perspective of internal system structure, structure reflects the internal relationship of the system, and function is the beneficial effect of things or methods. Research shows that the morphological structure of human organs, tissues and cells is the material basis of its function. Certain morphological structure has certain functions, that is, structure determines function, and specific morphological structure realizes specific functional activities. On the contrary, the functional state can also have a corresponding impact on the morphological structure. The two are interdependent and restrict each other. Sports quality refers to the various abilities of athletes in sports. It usually includes strength, speed, endurance and flexibility. In fact, sports qualities such as strength, speed, endurance and flexibility are the comprehensive performance of human body morphological structure, physiological function and metabolic status. They are the overall sports ability of athletes. At the same time, the development of sports quality has a certain impact on Athletes' morphological structure and physiological function. Among the three constituent factors, sports quality is the external performance of physical fitness. We regard the physical system structure of athletes and the physical structure of each subsystem as a system, whose form, function and sports quality are in a specific position and contribute their own functions. Each ability has its own specific constituent elements, and each element is determined by a specific form, content or function, thus forming the hierarchy of athletes' physical structure. From the general structure, it is a complex system composed of multi-level vertical system and multi system parallel horizontal system. In terms of its primary subsystem, it includes three subsystems: body shape, physiological function and sports quality. They constitute three interrelated subsystems that are relatively independent and interrelated. Each subsystem is divided into several levels of subsystems, thus forming the network system of athletes' physical fitness [8].

The square root method is used to calculate the weight of relevant indicators of special physical fitness of tennis players in Colleges and Universities Affiliated to Heilongjiang Province. The specific operation steps are as follows:

Calculate the product of each row element of the judgment matrix B, that is M_i, as shown in formula (1); (1) Mi=∏i=1nBij,(i=1,2,…n) Mi = \prod\limits_{i = 1}^n {{B_{{i_j}}},\left( {i = 1,\,2,\, \ldots n} \right)}

Calculate the value of the product M_t of each row of elements to the n-th power root, that is Wi¯ \overline {Wi} ; See formula (2); (2) W¯i=Mtn,(i=1,2,…n) {\bar W_i} = \root n \of {{M_t}} ,\left( {i = 1,\,2, \ldots n} \right)

In this paper, the order of fractions is an adaptive process related to local variance: (10) v=1+σx,y2−min(σx,y2)10×max(σx,y2) v = 1 + {{\sigma _{x,y}^2 - \min \left( {\sigma _{x,y}^2} \right)} \over {10 \times \max \left( {\sigma _{x,y}^2} \right)}} n represents the order of the matrix or the number of indicators at the same level.

Normalize the vector (W¯1,W¯2,…W¯n)T {\left( {{{\bar W}_1},{{\bar W}_2}, \ldots {{\bar W}_n}} \right)^T} , and the obtained value is the weight value of the corresponding index. See formula (3); (3) Wi=wi¯∑i=1nwi¯ {W_i} = {{\overline {{w_i}} } \over {\sum\limits_{i = 1}^n {\overline {wi} } }}

The main reason why the constructed judgment matrix is unreasonable is that experts and coaches judge the importance of indicators differently. Therefore, in order to avoid the self contradiction of importance between indicators at the same level, it is necessary to test the consistency of the final judgment matrix. According to AHP theory, when the consistency ratio CR < 0.1, it is considered that the constructed judgment matrix is relatively reasonable and ensures the relative accuracy of index weights at all levels. The specific operation steps of consistency test are as follows:

Calculate the maximum eigenvalue of the matrix, see equation (4); (4) λmax=1n∑i=1n(AW)iWi {\lambda _{\max }} = {1 \over n}\sum\limits_{i = 1}^n {{{{{\left( {AW} \right)}_i}} \over {{W_i}}}}

Calculate the value of the consistency index CI of the matrix, as shown in equation (5). (5) CI=λmax−nn−1 CI = {{{\lambda _{\max }} - n} \over {n - 1}}

Through the first round of expert questionnaire, the indicators with an expert consent rate of more than 70% are selected as the primary indicators. However, since the more index test items, the greater the amount of information, it is necessary to screen the indicators in the first round again, so that the established index system is more direct and the evaluation is easier to operate. The second expert questionnaire is used to screen the indicators again, and the expert survey method and expert experience are used to screen the indicators to further modify the primary indicators, but the premise of this method is that the researchers must have high consistency. Principal component analysis is a multivariate statistical analysis method that transforms multiple measured variables into a few irrelevant comprehensive indicators. Its advantage is that the principal component score obtained by principal component analysis is far less than the number of original variables, but the information loss is very small. The extracted principal components and the naming results of principal components according to the load after rotation are shown in Tables 3 and 4. KMO values are above 7.0, indicating that various indicators are suitable for principal component analysis, and the cumulative contribution rate is more than 75%, indicating that the analysis effect is good. According to principal component analysis (PCA, also known as principal component analysis, aims to use the idea of dimension reduction to transform multiple indicators into a few comprehensive indicators. In empirical research, in order to comprehensively and systematically analyze problems, we must consider many influencing factors. These factors are generally referred to as indicators and variables in multivariate statistical analysis [9]. Because each variable reflects some information of the research problem to varying degrees, and there is a certain correlation between the indicators, the information reflected by the obtained statistical data overlaps to a certain extent. When using statistical methods to study multivariable problems, too many variables will increase the amount of calculation and increase the complexity of the analysis. People hope that in the process of quantitative analysis, less variables are involved and more information is obtained. Finally, a special physical fitness index system of a college tennis player is obtained [10].

In the screening process, RSR (rank sum ratio) - a comprehensive evaluation method of nonparametric statistics is adopted. When this method is applied, it can quickly reflect the status and role of indicators in the evaluation without any exchange. RSR=ZR(mXn), where ZR represents the rank sum value of body shape, sports function and special quality indicators of college tennis players in Jiangsu Province, m is the number of indicators and n is the number of experts. Compare the value of each RSR with the value of each RSR to obtain the weight [11].

In order to intuitively and scientifically judge the level and level of special physical fitness and comprehensive physical fitness of college tennis players in a province, it is necessary to establish the grade evaluation standard of tennis special students' physical fitness and comprehensive physical fitness. According to the measurement and evaluation theory, the grade evaluation usually adopts the five grade evaluation method (i.e. upper, middle, upper, middle, lower and lower) [12]. The fifth grade evaluation can adopt both dispersion method and percentile method. Compared with the dispersion method, the percentile method not only has the advantages of the dispersion method, but also uses the median as the reference value and other percentiles as the discrete distance to divide the evaluation grade, instead of taking the average as the reference value and the standard deviation as the discrete distance. It is applicable to all kinds of data with normal distribution or non normal distribution, and also reduces the link that the normal test must be carried out on relevant data because the distribution characteristics of data are not clear before formulating the evaluation standard [13]. Especially for non normal distribution data, it can be evaluated more accurately. Therefore, percentile method is more and more used at home and abroad in recent years. Therefore, in order to objectively reflect the level and level differences between the first-class physical fitness index and comprehensive physical fitness of athletes, this study uses the percentile method to establish the first-class special physical fitness index and comprehensive physical fitness grade evaluation standard of college tennis players in a province, and obtains the grade position of the first-class index and comprehensive physical fitness of college tennis players in a province according to the grade standard.

Through the above evaluation results, we can find the basic situation of college tennis players' special physical fitness in a province, so that teachers can have a certain understanding of students' special physical fitness, and reasonably plan the teaching and training process, so as to provide a basis for the overall improvement of students' competitive ability. The indexes of special physical fitness of college tennis players in a province are selected, the weight of each index is established by analytic hierarchy process, and the evaluation standard of physical fitness of college tennis players is determined by percentile method. The evaluation index system is established by organically combining single evaluation and grade evaluation, which provides a basis for athletes to further check and diagnose the actual state of competitive ability [14].

Exercise load includes two aspects: exercise volume and exercise intensity. Load is the amount of stimulation to the body and an important aspect of exercise load. The body reaction caused by it is relatively stable. It also subsides slowly after relieving the load. Therefore, the measurement of competition load can be carried out by measuring the load. The measurement of load usually includes the time of practice, the number of times (groups), the total distance of practice, the total weight and so on. Exercise intensity refers to the degree of physiological stimulation of physical exercise on human body, which is commonly expressed by physiological indicators. Such as measuring the amount of exercise in school physical education by heart rate, the transformation of blood lactic acid, etc. Speed quality - the speed of the baseline movement, explosive force - the serving speed, endurance quality - the displacement and strength quality of the whole game - the forehand hitting speed.

Test tool: polar meter collects heart rate on site. It includes 10 team heart rate transmission belts and elastic belts, a rechargeable data transmitter, a computer data line, and Polar precision Performance training and analysis software.

Test method: the sampling frequency is 12 times / min until the end of the test. After the test, input the stored heart rate data into the computer through the data transmitter, number and classify the stored data, and conduct statistical analysis with Polar Precision Performance training and analysis software. According to the human body's response to exercise load, it is divided into four intensity levels based on the heart rate, that is, it is high intensity when the heart rate is more than 157 times every 60s; 156 ~ 139 times are medium strength; 138 ~ 120 times is low strength; The following 120 times are general activities. Test results and analysis: see Table 5.

In sports center, the change of rate can reflect energy metabolism, body function level, training load intensity and body function recovery. When athletes participate in sports and muscle activities, the increase of HR is related to exercise intensity, and the range of increase is also related to physical fitness level, duration and training level. When the variation range of heart rate is between 110–180 beats / zone, there is a significant linear relationship between heart rate and exercise intensity, oxygen uptake and energy metabolism. The latest view is that heart rate can reflect the comprehensive physiological stress level of the body. When the human body is in intense exercise, the body will produce a series of psychological stress reactions, which will play a positive role in the functional regulation and energy supply of human movement.

In the above experiment, the changes of the average heart rate of college tennis players in a province before, during and after the tennis game are described. The heart rate of the players before the game is within a normal range, which is significantly higher than the pre game value compared with the heart rate immediately after the game (P < 0.01). In the high-intensity round, the center rate has a more obvious change, which has a great relationship with the fast running, hitting and tense competition mood of the tested athletes. The heart rate of the athletes drops correspondingly in the 20s and 90s after the high-intensity. After the competition, after the athletes get the corresponding rest, the heart rate gradually recovers, and the heart rate of the test exercise will return to normal the next morning. We can see that in the college tennis competition in Jiangsu Province, the heart rate of athletes changes. With the change of competition load, the heart rate of athletes is also changing. During the interval of the competition, the load stops, and the heart rate of athletes falls back until it returns to normal. It can be seen that although the load intensity of College Students' tennis teaching competition is small, the change of heart rate can sensitively reflect the size of competition load.

The immediate heart rate of college students after tennis teaching competition was 112.17 + 6.47 BPM, which was significantly lower than that before the competition (P < 0.01), but the change range was small; The maximum heart rate after the high-intensity round in the game is 146bpm. The heart rate recovers obviously during the interval, and can fully recover to the pre game state the next morning. The change characteristics are obvious in the process of College Students' tennis competition, which can reflect the change of their competition load intensity, and can be used as an effective physiological index for college students' tennis load intensity monitoring. Therefore, we can see that the load intensity of College Students' tennis competition in a province is not large. During human exercise, blood lactic acid also increases gradually with the increase of exercise intensity. During light load exercise, the blood lactic acid value is not very high. With the gradual increase of intensity, when the load intensity exceeds a certain level, the blood lactic acid will rise sharply (about 80% ~ 90% of the maximum intensity). The average blood lactic acid level of the tested athletes before the competition is 1.58 + 0.41 mmol / L for men and 1.56 + 0.34 mmol / L for women. In quiet time, lactic acid is mainly produced by tissues with more energy consumption, such as nerve, retina, red blood cells and so on. Under normal conditions, the production and clearance of lactic acid are in dynamic balance. The blood lactic acid concentration is 1–2 mmol / L. there is no difference in the quiet value of exercise blood lactic acid between normal people and normal people. The special foundation of tennis is mainly reflected in speed strength and speed endurance. The fast attack and defense, fierce confrontation and multi shot back and forth in the competition require athletes to have high back and forth fast running ability of the bottom line. Athletes should have a certain level of lactic acid supply after the competition. Therefore, they should have a certain proportion of lactic acid supply system to participate in the competition. The level of blood lactic acid value after exercise reflects the athletes' exercise ability and ability to tolerate lactic acid. From the above experimental results, it can be seen that from the experimental results

It is calculated that the blood lactic acid level of athletes from the beginning of the competition to the end of the competition is 4.77 + 1.62 mmol / L for men and 4.11 + 2.13 mmol / L for women, which is 2–3 times that of quiet. The change of blood lactic acid is related to the energy system used during exercise, and also reflects the metabolic rate of muscle fibers. During the exercise of increasing intensity, the continuous increase of blood lactic acid shows that there is little change in blood lactic acid in the fierce tennis game. This may be because the intermittent rest time of tennis game is long, and the lactic acid is continuously generated and eliminated at the same time. Therefore, the accumulation of blood lactic acid is not much after the end of the whole game. This further shows that tennis is basically an anaerobic and lactic acid free sport. It can be seen that the load intensity of College Students' tennis competition in a province is not large.

Through the comparative analysis of college male tennis players in a province, it is found that their speed utilization rate is low, their service technology level and application ability are poor, and their mastery and understanding of service technology is not very stable. Although the speed utilization rate and one shot success rate of individual athletes are close to or even higher than those of high-level athletes, the average absolute speed and scoring rate are significantly lower than those of high-level athletes. Similarly, the comparative analysis of female tennis players of college students in Jiangsu Province shows that their speed utilization rate is also low, even lower than that of male players, and their service technology level and application ability are poor, and their mastery and understanding of service technology are also unstable. Through the comparison of service speed, we can know the intensity of athletes' competition in the process of competition, which reflects the small load of College Students' tennis competition in Jiangsu Province. Therefore, the training of tennis players in a province should not only take into account the service technology and the absolute speed of service, but also consider the tactical training of service, teach students according to their aptitude and strengthen training for weak links.