## 2 Materials and Methods
### Test Tools  
The AI motion capture system developed by China Dalian Ruidong Technology Co., Ltd. (Dalian, China) using two high-definition cameras from Japan SONY Company (Tokyo, Japan) were used for the AI motion capture. The focal length of the camera was set to 26 mm, the shooting frequency was set to 60 fps, and the shutter speed was set to 1/1200 s. Before carrying out the AI motion capture, space calibration was performed on the athletes' route, and the size of the calibration space was 5 m \(\times\) 5 m \(\times\) 2.5 m. The video resolution was 1920 \(\times\) 1080 P. The AI motion capture system automatically carried out human body key point recognition and 3D model reconstruction on the captured video. The 3D reconstruction model consisted of 21 landmark points. See Table 2 for the location of the landmark points. When we were manually analyzing the race walking video, we double clicked the Fastmove Motion 3D software (Fast Move, Dalian, China) icon on the computer desktop to enter the system home page. We clicked \"New\" to enter the workflow interface, entered the project name and camera number, selected a new DLT calibration, imported the DLT model file and calibration video into the system, and clicked \"Save Project\" after completing the DLT calibration as required. We clicked the \"New\" button in the workflow interface to add a new video group and to complete the video group creation and file addition. We clicked the \"Start\" button \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Name** & **Age** & **Height (cm)** & **Weight (kg)** & **Competition Results** & **Ranking** \\ \hline [PERSON] & 28 & 159 & 47.5 & 1:33:31 & 1 \\ [PERSON], [PERSON] & 25 & 161 & 46.4 & 1:34:47 & 2 \\ [PERSON] & 25 & 163 & 48.2 & 1:35:48 & 3 \\ [PERSON] & 29 & 163 & 46.4 & 1:35:50 & 4 \\ [PERSON] & 22 & 165 & 49.5 & 1:36:19 & 5 \\ [PERSON] & 24 & 170 & 50.8 & 1:37:43 & 6 \\ [PERSON] & 27 & 168 & 53.1 & 1:39:13 & 7 \\ [PERSON], [PERSON] & 26 & 163 & 44.7 & 1:39:29 & 8 \\ [PERSON] & 24 & 162 & 46.5 & 1:39:56 & 9 \\ [PERSON] & 29 & 167 & 48.4 & 1:40:12 & 10 \\ [PERSON] & 29 & 163 & 46.3 & 1:41:31 & 11 \\ [PERSON] & 23 & 161 & 46.6 & 1:43:59 & 12 \\ [PERSON] & 29 & 160 & 43.8 & 1:44:27 & 13 \\ [PERSON] & 21 & 164 & 48.7 & 1:44:53 & 14 \\ [PERSON] & 27 & 166 & 52.4 & 1:45:42 & 15 \\ \hline \hline \end{tabular} \({}^{*}\)The subjects are from an adult women’s 20 km race walking event.  
\end{table} 
Table 1: Basic information on the chosen subjects * (\(N=15\)). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Number** & **Name** & **Position** \\ \hline
1 & Head & Vertex \\
2 & Chin & Cusp of chin \\
3 & Neck & Midpoint of neck \\
4 & Lshoulder & Midpoint of left shoulder joint \\
5 & Rshoulder & Midpoint of right shoulder joint \\
6 & LElbow & Midpoint of left elbow joint \\
7 & RElbow & Midpoint of right elbow joint \\
8 & LWrist & Midpoint of left wrist \\
9 & RWrist & Midpoint of right wrist \\
10 & LHand & Midpoint of left hand \\
11 & RHand & Midpoint of right hand \\
12 & LHip & Left hip midpoint \\
13 & RHip & Right hip midpoint \\
14 & LKnee & Midpoint of left knee joint \\
15 & RKnee & Midpoint of right knee joint \\
16 & LAnkle & Midpoint of left ankle joint \\
17 & RANkle & Midpoint of right ankle joint \\
18 & HLeel & Midpoint of left heel \\
19 & RHeel & Midpoint of right heel \\
20 & LBigToe & Midpoint of the first metatarsal bone of the left foot \\
21 & RBigToe & Midpoint of the second metatarsal bone of the right foot \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Locations of landmark points of 3D reconstruction model. to enter the motion analysis mark interface, and gradually complete the file processing, analysis processing, data processing, and the processing of other contents (see Figure 1 for the data processing interface). After processing the 3D analytical data, we clicked \"Save\" and \"Next\" to enter the curve representation interface. At this time, it was possible to view the original data and the filtered data.