Author(s): INOUE, Y., KAWAKUBO, Y., Institution: OSAKA INSTITUTE OF TECHNOLOGY, Country: JAPAN, Abstract-ID: 895

Introduction
Many people are aware of their lack of exercise, but find it difficult to exercise continuously. In recent years, sports training has been conducted using Virtual Reality (VR) technology. The advantages of VR include the ability to practice in confined spaces, under any weather conditions, and even alone. Based on the benefits above, we decided to develop a tennis practice support system using VR with the aim of enabling enjoyable and continuous physical activity. The effectiveness of the developed system was verified by quantifying the hit rate to the racket and the number of successful ball returns to the opponents court. In addition, we also examined the participants’ gaze during the tennis exercise．
Methods
Sixteen university students participated in the experiment. They wore a head-mounted display, held Meta Quest Touch Pro controllers in both hands, grabbed a VR racket, and practiced volleys and strokes. Balls were launched at three-second intervals from a ball launcher in the VR space, and the participants returned the ball to a target on the opponents court.　Training consisted of pre-test, practice, and post-test. In the pre-test and post-test, the players played 50 strokes and 50 volleys, respectively. In the practice session, they played 100 strokes and 100 volleys. Two modes of target movement were conducted: the first was a mode in which the target moved randomly for each ball, and the second was a focused mode in which the target moved every five balls so that the participants could concentrate on one spot at a time.　The participants were divided into two groups: a random group and a focused group. The measurement items were eye gaze, electrocardiogram, stroke and volley performance, and responses from post-experience questionnaire.
Results and Discussion
Both groups showed a significant increase in stroke and volley scores in the post-test compared to the pre-test. However, no significant differences were observed between the groups. The increase in scores in the post-test suggests that the developed practice system may have been effective. However, since no significant differences were shown between the target movement modes, it is necessary to study more effective ways of moving the target. The results of the eye movement showed that the players took a closer look at the racket and the ball launcher than the target with significant differences in the eye movement between these objects. Both groups tended to focus more on the target in the post-test than in the pre-test. The heart rate during the exercise showed an increase of about 10 beats per minute compared to that at rest. However, some participants reported that the intensity of the exercise felt low in the post-experience questionnaire, suggesting the need to increase the intensity of the exercise by randomizing the position of the ball.